RTI Piranha Reference Manual

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RTI Piranha Reference Manual | Manualzz

Piranha

&

QABrowser

Reference Manual - English - Version 5.5C

RTI article number: 9629050-10

Welcome to Piranha and the QABrowser

The Piranha is an X-ray Analyser/Multimeter for everybody working with Quality Assurance and

Service of X-ray systems.

Notice

III

NOTICE

RTI Electronics AB reserves all rights to make changes in the Piranha, the

QABrowser, and the information in this document without prior notice.

RTI Electronics AB assumes no responsibility for any errors or consequential damages that may result from the use or misinterpretation of any information contained in this document.

Copyright © 2001-2014 by RTI Electronics AB. All rights reserved.

Content of this document may not be reproduced for any other purpose than supporting the use of the product without prior permission from RTI Electronics

AB.

Palm, palmOne, and TUNGSTEN are trademarks of PalmOne, Inc.

HotSync and Graffiti are trademarks of ACCESS CO., LTD

Microsoft, Windows, Win32, Windows XP, 2003, Vista, 7, and 8 are either registered trademarks or trademarks of Microsoft Corporation in the United States and/or other countries.

BLUETOOTH is a trademark owned by Bluetooth SIG, Inc., USA.

Contact Information -

World-Wide

RTI Electronics AB

Flöjelbergsgatan 8 C

SE-431 37 MÖLNDAL

Sweden

Phone: Int. +46 31 7463600

Fax: Int. +46 31 270573

E-mail

Sales: [email protected]

Support: [email protected]

Service: [email protected]

Web site: http://www.rti.se

2014-06/5.5C

Contact Information -

United States

RTI Electronics Inc.

33 Jacksonville Road, Bldg. 1,

Towaco, NJ 07082,

USA

Phone: 800-222-7537 (Toll free)

Int. +1-973-439-0242

Fax: Int. +1-973-439-0248

E-mail

Sales: [email protected]

Support: [email protected]

Service: [email protected]

Web site: http://www.rti.se

Piranha & QABrowser Reference Manual

IV

Intended Use

Intended Use of the Piranha System

Accessory to diagnostic X-ray equipment to be used as an electrometer. Together with external probes it is to be used for independent service and quality control, as well as measurements of kerma, kerma rate, kVp, tube current, exposure time, luminance, and illuminance within limitations stated below.

If installed according to accompanying documents, the product is intended to be used together with all diagnostic X-ray equipment except for:

- therapeutical X-ray sources.

- X-ray equipment with tube potential below 18 kV.

- X-ray equipment on which the instrument cannot be mounted properly, e.g. equipment where the beam field size is narrower than the active part of the detector.

- specific types of X-ray equipment listed in the instructions for use or in additional information from the manufacturer.

With the X-ray installation in stand-by conditions without patients present, the product is intended to be used:

- to provide the operator with information on radiation beam parameters that might influence further steps in an examination but not an ongoing exposure.

- for assessing the performance of the X-ray equipment.

- for evaluation of examination techniques and procedures.

- for service and maintenance measurements.

- for quality control measurements.

- for educational purposes, authority supervision etc.

The product is intended to be used by hospital physicists, X-ray engineers, manufacturer's service teams, and other professionals with similar tasks and competencies. The operator needs a short training to be able to use the product as intended. This training can be achieved either by careful study of the manual, studies of the built-in help function in measurement software or, on request, in a short course ordered from the manufacturer.

The product is intended to be used inside X-ray rooms ready for clinical use and can safely be left switched on and in any measuring mode in the vicinity of patients.

The product is NOT intended to be used:

- for direct control of diagnostic X-ray equipment performance during irradiation of a patient.

- so that patients or other unqualified persons can change settings of operating parameters during and immediately before and after measurements.

Piranha & QABrowser Reference Manual 2014-06/5.5C

Contents

1

Table of Contents

1.

1.1

..................................................................................................... 5

1.2

..................................................................................................... 5

1.3

..................................................................................................... 6

1.4

..................................................................................................... 6

2.

2.1

..................................................................................................... 9

2.2

..................................................................................................... 12

2.3

..................................................................................................... 12

2.4

..................................................................................................... 13

2.4.1

2.4.1.1

General ..........................................................................................................13

2.4.1.2

..........................................................................................................13

2.4.1.3

..........................................................................................................14

2.4.1.4

..........................................................................................................21

2.4.1.5

..........................................................................................................24

2.4.2

2.5

..................................................................................................... 29

2.5.1

2.5.2

2.5.3

2.5.4

2.6

..................................................................................................... 32

2.6.1

2.6.2

3.

3.1

..................................................................................................... 37

3.2

..................................................................................................... 37

3.3

..................................................................................................... 38

3.3.1

3.3.2

3.3.3

3.3.3.1

..........................................................................................................45

3.3.3.2

..........................................................................................................48

3.3.3.3

..........................................................................................................50

3.3.3.4

..........................................................................................................52

3.4

..................................................................................................... 52

3.4.1

3.4.2

3.5

..................................................................................................... 57

3.6

..................................................................................................... 59

3.6.1

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Piranha & QABrowser Reference Manual

2

Contents

3.6.2

Start here! .............................................................................................................63

3.7

..................................................................................................... 63

3.7.1

3.7.2

3.7.3

3.7.4

3.7.5

3.7.6

3.7.7

Units Setup .............................................................................................................64

Log Setup .............................................................................................................65

3.8

..................................................................................................... 67

3.9

..................................................................................................... 68

3.10

..................................................................................................... 70

3.10.1

.............................................................................................................70

3.10.2

.............................................................................................................72

4.

4.1

..................................................................................................... 74

4.2

..................................................................................................... 74

4.3

..................................................................................................... 75

4.3.1

4.3.2

4.4

..................................................................................................... 78

4.4.1

4.4.2

4.5

..................................................................................................... 82

4.6

..................................................................................................... 83

4.7

..................................................................................................... 83

4.8

Linearity ..................................................................................................... 85

4.9

..................................................................................................... 86

5.

5.1

..................................................................................................... 88

5.2

..................................................................................................... 89

5.2.1

5.2.2

5.2.3

5.2.3.1

..........................................................................................................96

5.2.3.2

..........................................................................................................97

5.2.4

5.3

..................................................................................................... 101

5.3.1

5.3.2

5.3.3

5.4

..................................................................................................... 103

5.4.1

5.4.2

5.4.3

5.4.4

5.5

..................................................................................................... 113

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Contents

3

5.5.1

5.5.2

5.5.3

5.5.4

General .............................................................................................................113

5.5.5

5.5.6

5.5.7

5.5.7.1

..........................................................................................................120

5.5.7.2

..........................................................................................................120

5.5.7.3

..........................................................................................................122

5.5.7.4

..........................................................................................................122

5.5.8

5.5.9

5.5.10

.............................................................................................................124

5.6

..................................................................................................... 125

5.6.1

5.6.2

5.6.3

5.6.4

5.7

CT ..................................................................................................... 134

5.7.1

5.7.2

5.7.3

CT kVp .............................................................................................................134

5.8

..................................................................................................... 137

5.8.1

5.8.2

5.9

..................................................................................................... 143

5.9.1

5.9.2

6.

6.1

..................................................................................................... 148

6.2

..................................................................................................... 148

7.

7.1

..................................................................................................... 152

7.2

..................................................................................................... 154

7.2.1

7.2.2

7.3

..................................................................................................... 156

8.

Index

..................................................................................................... 169

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Piranha & QABrowser Reference Manual

Chapter 1

Introduction

1. Introduction

About this Manual

5

1 Introduction

1.1

About this Manual

This manual is divided into a few main parts.

1.

A general description of the Piranha.

2.

A general description of the QABrowser.

3.

Some theoretical background and basic principles.

4.

Descriptions on performing measurements with the system for different modalities.

5.

Description of different accessories for the Piranha.

6.

Troubleshooting tips, an FAQ, and a glossary.

Users who use the Piranha with only a PC and Ocean are recommended to read at least the following topics:

Introduction

Description of the Piranha

Measurements with the Piranha System

This manual gives a short introduction to handheld computers and enough of information to get started and use it with the Piranha. However, it is advised (if you are going to use a handheld computer) to study the manual that is included with your handheld computer to get familiar with its capabilities.

Pictures in included manuals for detectors and probes may include an ADI module (a small module with a connector attached to the detector cable). ADI modules are used to store calibration data and used by other products than the Piranha from RTI Electronics.

For the Piranha system, calibration data is instead stored inside the system. See section Managing Detector Calibrations 35 for more information.

The handheld computer is sometimes called "Palm" or "Palm computer" in this manual, this is referring to all types of handheld computers running Palm OS or Windows Mobile that currently are possible to use with the Piranha and the QABrowser.

Typographical Rules

Terms in

bold

face are references to texts on screenshots, like buttons and texts, and menu items. Other terms are

italicized

.

1.2

Introduction to the Piranha

Congratulations to your purchase of a Piranha. You have now in your hand the most powerful tool for X-ray analysis. It has been carefully designed to meet the needs of both standard QA applications as well as advanced service/repair/calibration of modern

X-ray systems, while still being very simple and intuitive to use. It can measure all the required parameters such as kVp, exposure time, dose, HVL, Total Filtration, dose/ pulse, dose rate, tube current, mAs, waveforms, and much more.

The Piranha can be used in two different ways:

As a "meter" with a handheld computer and the QABrowser or a PC with Ocean

Quick-Check.

As a complete "QA-system" with a PC and the Ocean software.

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6

1. Introduction

Introduction to the Piranha

This manual describes the Piranha and the QABrowser. The PC software, Ocean, is described in a separate manual.

The Piranha system's main features are:

Very easy and intuitive to use

Accurate

Active Compensation - No manual corrections are needed

Measures on all modalities with one detector

Specially designed measuring modes for pulsed waveforms

Compact

QABrowser or Ocean is used for control and data processing

Waveform analyser

USB and Bluetooth interface

Free upgrade of firmware

New and unique design

Free upgrades of the firmware (the software resident in the cabinet and measuring modules) are available on RTI Electronics Web site at http://www.rti.se

.

If you have questions, comments, or feel that some functionality is missing, you are welcome to contact us at RTI Electronics at [email protected]

. You can of course also call or send a fax (see notice section for details).

1.3

PC Requirements

To run the RTI Updater, the QABrowser Updater, and Ocean the following is required:

Minimum requirements

Windows XP, 2003, Vista, 7/8 32-bit, or 7/8 64-bit.

Pentium class 300 MHz, 64 MB RAM (24 MB free), 60 MB of HD

1

USB port

Display and graphics card with at least 800×600 resolution

Recommended requirements

Windows 7/8 32-bit or 8 64-bit

Pentium class 500 MHz, 128 MB RAM (32 MB free), 100 MB HD

USB port

CD/DVD-ROM for installation

Internet connection for updates (Recommended)

1

: Virtual memory and available hard drive space. Microsoft recommends that you have at least 20 % of your total HD space free for virtual memory.

1.4

Palm OS Computer Requirements

To run the QABrowser the following is required:

Minimum requirements

PalmOS v5.0 or higher

16 MB of memory

Colour screen with a resolution of 320×320 pixels

Palm connection: Bluetooth wireless

Recommended requirements

Piranha & QABrowser Reference Manual 2014-06/5.5C

1. Introduction

Palm OS Computer Requirements

RTI Handheld Display or Palm Tungsten E2/TX

Bluetooth wireless.

7

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Piranha & QABrowser Reference Manual

Chapter 2

Description of the Piranha

2 Description of the Piranha

2. Description of the Piranha

Indicators and Connectors

9

2.1

Indicators and Connectors

The Piranha comes in a lot of different models, the external design is basically the same for all models (except for the External Probe port).

Edge:

External Probe port

(on some Piranha models)

Detector area

The rectangular marking indicates where the active detector area is located. The detector surface is located 10 mm below the surface, see section

Specifications, Piranha

14

. Minimum X-ray field is

3×21 mm.

The recommended field size is shown as red corners. (20×40 mm).

Power switch

(on edge)

Turns the Piranha on and off

Indicators

for charging, status, and Bluetooth

USB Palm charger port output

(not used)

The

USB port

is used when using RTI Updater to update the internal firmware. It can also be used when the Piranha is used together with a PC running the QA software

Ocean. Note that the USB connector cannot be used when connecting to a handheld computer. The system is then powered from the PC via the USB cable. The PC however have a limited USB power output, so when fast charging is needed the power supply needs to be connected here. This is also possible when using the Bluetooth link to communicate with the Palm or PC. The port is marked

USB

.

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2. Description of the Piranha

Indicators and Connectors

The orange indicator for

Charging of batteries

is lit when charging is active.

Note that charging is possible even when the power switch is off.

The multi-coloured indicator for

Status

shows the status of the system, e.g.

battery level as described below. Also works as

Power indicator

, one of the colours will light when the Piranha is on.

The blue indicator for

Bluetooth

is lit when the

Bluetooth interface is active and discoverable.

Battery level

The status indicator is used to show the battery level of the Piranha.

1. Starting a system running on batteries the status indicates for 3 seconds:

- Green if battery level over 25 % (4 h left)

- Yellow if battery level between 10 and 25 % (1½-4 h left)

- Red if battery level below 10 % (<1½ h left).

The idea is to get a quick indication when powering on the system if it will take me through today's work.

2. When running on batteries the status indicator shows:

Status colour

Green

Yellow

Red

Flashing red

Running time left

>2 hours

>1 hours

>15 minutes

<15 minutes

You may also check the battery level in the QABrowser, see section Power

Status

67

. For Ocean on the PC, please see the Ocean manual.

See section Power & Communication Specifications

13

for more information about battery charging and discharging times.

External Probe port

and

Opening for filter position viewing

Here you attach the external probes that come with some models of the Piranha. The port is marked

EXT

. Not all models have this port.

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2. Description of the Piranha

Indicators and Connectors

11

The small square opening above may be used for monitoring the filter position inside the Piranha.

Product marking

Indicates the model of you

Piranha, as well as the version, serial number, and applicable conformity markings.

Power switch

Turns the Piranha on and off (Marked

1/0)

Camera thread

for mounting the Piranha to a holder.

Attachment for

Safety strap

The

Power switch

is used to turn the Piranha on and off. Piranha has several ways of saving power when it is inactive, but must be powered off manually since there is no auto-power off function.

Below a block diagram of a typical Piranha system is shown.

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2. Description of the Piranha

Indicators and Connectors

2.2

Setting Up the Piranha for the First Time

Before you use your Piranha for the first time, please do the following:

Attach the external power supply.

Charge the system for 16 hours.

Then continue according to the following section.

2.3

Setting Up the Piranha

To set up the Piranha:

1. Power on the Piranha using the power switch. Optionally you may connect the power supply.

2. Place the Piranha under the tube or mount the holder and HVL stand for positioning of the Piranha in the X-ray field. The stand allows you to position the Piranha (or the external Dose Probe) and HVL filters in any angle including upside-down. Use the light-field or other help to position the Piranha in the X-ray field. The Piranha detector is not sensitive for different field sizes as long as the entire sensitive detector area is irradiated, but try to keep the field size down to minimize scattering.

It is also recommended to position the Piranha in such a way that the detector area is orientated perpendicular to the anode/cathode axis, to avoid the heel effect.

Recommended field size is 20×40 mm.

3. Connect with Handheld via Bluetooth, or with Ocean via included USB cable or via

Bluetooth.

Piranha & QABrowser Reference Manual 2014-06/5.5C

2. Description of the Piranha

Hardware and Specifications

13

2.4

Hardware and Specifications

Specifications are valid after a warm-up time of one minute and presuming reference conditions. All specifications are for use together with the Piranha unless otherwise stated. All specifications can be changed without prior notice. RTI Electronics AB assumes no responsibility for any errors or consequential damages that may result from the misuse or misinterpretation of any information contained in these specifications.

2.4.1

Piranha internal detector (Internal detector)

2.4.1.1

General

With the Piranha internal detector you will manage most of your measurements. Tube voltage, exposure time, dose, and dose rate are measured for all kinds of modalities: conventional radiography, fluoroscopy, pulsed fluoroscopy, cine, mammography, dental, panoramic dental, and CT (kVp only, not dose and doserate). In one exposure, the detector provides tube voltage, time, dose, dose rate, quick-HVL, and estimated total filtration on radiographic, fluoroscopic, dental, and CT exposures. On pulsed radiation and cine, also dose per pulse and pulse rate are measured. The Piranha internal detector is very sensitive and can measure peak tube voltage for as low outputs as

50 kV / 0.050 mA at 50 cm.

Typically the exposure time has to be at least 5 ms to get a kVp value but it depends on the waveform. On modern X-ray generators (high-frequency with fast rise and fall times) the peak tube voltage can normally be measured with exposure time as short as 1 ms.

Dose and time values will be given for even shorter exposure times.

The estimations of total filtration and Quick-HVL are done from one single exposure using a combination of detector and filters in the Piranha. In situations when the total filtration cannot be automatically estimated, a "standard" HVL measurement may be required. All measured kVp and dose values measured with the Piranha are automatically compensated for the actual beam/radiation quality. This means that no manual corrections of measured data is needed.

The range indicator can be viewed behind a little lid, that can be pushed to the side. Make sure to close it afterwards, to avoid light leaking into the detector.

2.4.1.2

Power & Communication Specifications

Power Source

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14

2. Description of the Piranha

Hardware and Specifications

Power supply

Battery operated

External power

Power output

5 V AC/DC adapter with Mini-USB connector, internal battery, or

USB cable supply from PC.

One 2000 mAh Li-Ion battery. Operation time typically 15 hours.

Typical charging times are listed below.

100-240 V AC 50/60 Hz with external adapter.

On connector marked "5V OUT" for supply/charging of Palm.

Only functional when AC/DC adapter is connected to USB port.

Typical Battery Charging and Running Times

Capacity

50 %

80 %

90 %

100 %

Running time

7½ h

12 h

13½ h

15 h

Charging time

Using Power supply USB, Piranha ON USB, Piranha OFF

1½ h (90 min)

2½ h (150 min)

3¼ h (195 min)

5 h (300 min)

3½ h

6 h

7 h

8½ h

17 h

27 h

30 h

32 h

Note that other mains power solutions that uses a regular USB cable to connect to the

Piranha, will behave like USB in the table.

Communication

USB

Bluetooth

Max 12 Mbit/s (USB v1.1)

115 kbit/s

2.4.1.3

Specifications, Piranha

The inaccuracy is here defined as the root of the square sum of systematic errors, which has not been eliminated, and random errors (dispersion around a mean value).

The calculation of the inaccuracy is based on 15 different measurements and with a confidence level of 95 %. Of the total inaccuracy, random error is 20 % and general inaccuracy is 80 %.

Note

: Irradiation time is often called exposure time in daily use.

General

Operating temperature and relative humidity

Storage temperature

Operating air pressure

15 – 35 °C at <80 % relative humidity

–10 °C to +50 °C

Minimum 80 – 106 kPa

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2. Description of the Piranha

Hardware and Specifications

15

Reference conditions

Temperature

Relative humidity

Air pressure

X-ray field size

+18 °C to +23 °C

50 %

101.3 kPa

Inside the Piranha top panel.

Calibration is done with field size typically 5 mm less than the size of the top panel.

Radiation quality

Radiography

Mammography

CT

70 kV, 2.5 mm Al

28 kV, 30 µm Mo

120 kV, 2.5 mm Al

Note:

The reference conditions are given in reference to the IEC61674 standard.

Physical dimensions

Detector area

Detector position

Size

Weight

3 × 21.1 mm

10 mm below top panel, as indicated in figure below and by a 3 mm rim on 3 edges.

133 × 75 × 26 mm (5.2" × 2.9" × 1.02")

Approximately 405 g

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Piranha & QABrowser Reference Manual

16

2. Description of the Piranha

Hardware and Specifications

Parameters

Tube voltage (kVp)

The average of all samples with compensation for the ripple

(default method)

Irradiation time (Exposure time)

Time

Air kerma (Dose)

Measured air kerma (may be called dose or air kerma in this manual)

Air kerma rate (Dose rate)

Average air kerma rate (may be called dose rate or air kerma rate in this manual)

Total Filtration

Estimation of total filtration (for conventional radiography, fluoroscopy, dental, and CT)

Quick-HVL

Half Value Layer

Estimation of Half Value Layer (for conventional radiography, fluoroscopy, dental, mammography, and CT)

Standard HVL using filters for evaluation on radiography, fluoroscopy, dental, and mammography (all for both pulsed and conventional)

kV waveform

Dose rate waveform

Waveform is calculated based on detector signals measured after different thickness of filtration.

Signal measured from radiation detector (solid-state detector).

Measuring range and inaccuracy

Radiography, Fluoroscopy, and Dental

Parameter kVp (standard)

W / 3 mm Al

kVp dental

W / 3 mm Al

Irradiation time

Air kerma (Dose)

2

RQ

R1

R1

Range

35 – 160 kV

35 – 105 kV

0.1 ms – 2000 s

1 – 65535 pulses

0.7 µGy – 1000 Gy with wide range option

(WR)

Air kerma rate

2

(Dose rate)

with wide range option

(WR)

-Free run

-High Sensitivity

-Low Sensitivity

Estimated total filtration

Quick-HVL

Inaccuracy

±1.5 %

±1.5 %

Resolution

4 digits

(10 or 100 V)

As above

±1 % or ±0.5

ms

±1 pulse

±5 %

0.5 ms

1 pulse

15 nGy – 1000 Gy

(2 µR – 100 kR)

10 µGy/s – 450 mGy/s 3

15 nGy/s – 450 mGy/s 3

1.7 µR/s – 50 R/s

0.1 mR/min – 3000 R/min

±5 % or ±7 nGy/s

±5 % or ±0.8

µR/s

±5 % or ±0.05

mR/min

(for Irr. time >20 ms)

Typ. noise:

3 nGy/s

15 nGy/s – 12 mGy/s

2

150 nGy/s – 12 mGy/s 2

25 µGy/s – 450 mGy/s 2

1.0 – 90 mm Al

(full kV range)

±5 % or ±7 nGy/s

±5 % or ±7 nGy/s

±5 % or ±0.1

µGy/s

±10 % or ±0.3

mm

±15 % >50 mm Al

(60 – 120 kV, HF/DC,

>10 µGy/s)

Typ. noise:

3 nGy/s

2 digits

(0.1 or 1 mm)

1.2 – 14 mm Al 4

(50 – 150 kV)

±10 % or ±0.2

(60 –

>10 µGy/s) 1 mm

120 kV, HF/DC,

3 digits

(0.01 or 0.1 mm)

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2. Description of the Piranha

Hardware and Specifications

17

Note 1

: This is valid for a tube with 14° anode angle. The HVL for a 22° anode is typically 0,5 mm lower (@ 80 kV, 3 mm TF).

Note 2

: All kerma and kerma rate ranges, inaccuracy, and resolution figures are valid for product version 2 and higher of the Piranha.

Note 3

: The Kerma rate is calculated as the Kerma (Dose) divided by the Irradiation time. See also Waveforms and Triggers

82

.

Note 4

: The HVL range is valid if also the TF is within its specified range. For high TF at high kV the HVL range may be limited by this.

Mammography

Parameter kVp (standard)

Mo / 30 µm Mo

Mo / 25 µm Rh

Rh / 25 µm Rh

W / 50 µm Rh 3

W / 0.50 mm Al 5

Mo / 1.0 mm Al

W / 50 µm Ag

W / 75 µm Ag

W / 50 µm Rh (Gio)

W / 0.70 mm Al

W / 50 µm Ag (Sel) 4

W / 50 µm Rh (Sel) 4

kVp (optional)

Mo / 30 µm Mo +

+ 2 mm Al

Mo / 2.0 mm Al

RQ

M1

M3

M4

M6 3

M7 5

M8

M10

M11

M12

M15

M16 4

M17 4

18 – 49 kV

22 – 46 kV

25 – 49 kV

20 – 49 kV

20 – 48 kV

18 – 49 kV

20 – 40 kV

20 – 40 kV

22 – 35 kV

20 – 49 kV

22 – 39 kV

22 – 39 kV

M1d

M2

Range

25 – 35 kV

Irradiation time

Air kerma (Dose)

with wide range option

(WR)

Air kerma rate

1

(Dose rate) with wide range option

(WR)

-Free run

-High Sensitivity

-Low Sensitivity

1

Inaccuracy

±1.5 % or ±0.7 kV

±2 % or ±1 kV

±2 % or ±1 kV

±2 % or ±1 kV

±2 % or ±1 kV

±2 % or ±1 kV

±2 % or ±1 kV

±2 % or ±1 kV

±2 % or ±1 kV

±1.5 % or ±0.7 kV

±2 % or ±1 kV

±2 % or ±1 kV

±2 % or ±1 kV

18 – 49 kV

0.1 ms – 2000 s

1 – 65535 pulses

5 µGy – 1500 Gy

±2 % or ±1 kV

±1 % or ±0.5 ms

±1 pulse

±5 %

±5 %

25 nGy – 1500 Gy

3 µR – 150 kR

10 µGy/s – 750 mGy/s 2

25 nGy/s – 750 mGy/s

30 µR/s – 86 R/s

1.8 mR/min – 5100 R/ min

2

±5 % or ±12 nGy/s

±5 % or ±1.5 µR/s

±5 % or ±0.1 mR/min

(for Irr. time >20 ms)

25 nGy/s – 20 mGy/s

0.25 µGy/s – 20 mGy/s

45 µGy/s – 750 mGy/s

±5 % or ±12 nGy/s

±5 % or ±12 nGy/s

±5 % or ±0.2

µGy/s

Resolution

4 digits

(10 V)

4 digits

(10 V)

0.5 ms

1 pulse

Typ. noise:

6 nGy/s

Typ. noise:

6 nGy/s

Note 1

: All kerma and kerma rate ranges, inaccuracy, and resolution figures are valid for product version 2 and higher of the Piranha.

Note 2

: The Kerma rate is calculated as the Kerma (Dose) divided by the Irradiation time. See also Waveforms and Triggers

82

.

Note 3

: The M6 (

W / 50 µm Rh)

, M10 (

W / 50 µm Ag),

and M15 (

W / 0.70 mm Al

) calibrations are suitable for the Hologic Selenia Dimensions and Fuji Amulet.

Note 4

: The M16 (

W / 50 µm Ag (Sel)

) and M17 (

W / 50 µm Rh (Sel)

) calibrations are suitable for

Hologic Selenia with W anode..

Note 5

: The M7 (

W / 0.5 mmAl

) calibration is suitable for Philips MicroDose Mammography

(Sectra).

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2. Description of the Piranha

Hardware and Specifications

Parameter

Quick-HVL

6

Mo / 30 µm Mo

Mo / 25 µm Rh

Rh / 25 µm Rh

W / 50 µm Rh

W / 0.50 mm Al

Mo / 1.0 mm Al

W / 50 µm Ag

W / 75 µm Ag

W / 50 µm Rh (Gio)

W / 0.70 mm Al

W / 50 µm Ag (Sel)

W / 50 µm Rh (Sel)

RQ Range

M1

M3

M4

M6

M7

M8

M10

M11

M12

M15

M16

M17

0.19 – 0.47 mm Al

0.31 – 0.52 mm Al

0.33 – 0.60 mm Al

0.37 – 0.75 mm Al

0.24 – 0.64 mm Al

0.31 – 0.68 mm Al

0.34 – 0.69 mm Al

0.41 – 0.79 mm Al

0.37 – 0.66 mm Al

0.27 – 0.81 mm Al

0.34 – 0.69 mm Al

0.37 – 0.66 mm Al

Inaccuracy

±10 %

Resolution

3 digits

(0.001 mm)

Note 6

: The Quick-HVL for mammography is only available for Piranhas with product version 2 and higher.

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Hardware and Specifications

19

Computed Tomography

Parameter kVp (standard)

W / 3.0 mm Al

W / 3 mm Al + 1.2 mm Ti

(Siemens Straton (Siem1))

2

RQ

C1

Range

C3

2

C4

2

45 – 160 kV

75 – 145 kV

75 – 145 kV

GECT (7°)

2, 3

Acquillion 64

(Toshiba)

2

GECT (10.5°)

2, 3

C5

2

75 – 145 kV

Irradiation time

Air kerma (Dose)

C6

2

65 – 150 kV

0.1 ms – 2000 s

1 – 65535 pulses

-

±1.5 %

Inaccuracy

±1 % or ±0.5 ms

±1 pulse

-

Resolution

4 digits

(10 or 100 V)

0.5 ms

1 pulse

-

Estimated total filtration

Quick-HVL

C1

C6

C1

1.5 – 90 mm Al

(75 – 160 kV)

1.2 – 14 mm Al

(75 – 150 kV)

±10 % or ±0.3 mm

±15 % >50 mm Al

(75 – 120 kV, HF/DC,

>10 µGy/s)

±10 % or ±0.2 mm

(75 – 120 kV, HF/DC,

>10 µGy/s) 1

2 digits

(0.1 or 1 mm)

3 digits

(0.01 or 0.1 mm)

Note 1

: This is valid for a tube with 14° anode angle. The HVL for a 22° anode is typically 0,5 mm lower (@ 80 kV, 3 mm TF).

Note 2

: The C3 and higher numbered calibrations are only available for product versions 2.0 or higher.

Note 3

: The C4 (

GECT (7°)

) is suitable for all GE CT tubes which have a 7° anode angle as well as other manufacturers CT tubes and replacement tubes with a 7° anode angle. The C6 (

GECT

(10.5°)

) is suitable for GE CT tubes with a 10.5° anode angle..

Pulses

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2. Description of the Piranha

Hardware and Specifications

Parameter

Dose/pulse

Range

2.5 µGy/pulse - 60 kGy/pulse

1 with wide range option (WR)

Pulse dose rate

with wide range option (WR)

Min. output peak dose rate

- High Sensitivity

- Low Sensitivity

Pulse rate

Pulse width

Duty cycle

Minimum pulse width

- High Sensitivity

- Low Sensitivity

Minimum ripple

(pulse top to bottom)

Irradiation time

8 nGy/pulse - 60 kGy/pulse

1

Lower limit 10 µGy/s (70 mR/min), otherwise same as for air kerma rate.

Lower limit 10 µGy/s (70 mR/min) otherwise, same as for air kerma rate.

dose rate (min. pulse width)

4 µGy/s (4 ms) / 30 µGy/s (0.5 ms)

20 µGy/s (4 ms) / 160 µGy/s (0.5 ms)

0.5 – 180 Hz, resolution 0.5 Hz

4 ms - 2000 s

5 - 95 % pulse width (min. dose rate)

4 ms (4 µGy/s) / 0.5 ms (30 µGy/s)

4 ms (20 µGy/s) / 0.5 ms (160 µGy/s)

50 %

1 – 65535 pulses, resolution 1 pulse

Note 1

: Max dose/pulse depends on the pulse length.

Note 2

: All kerma and kerma rate ranges, inaccuracy, and resolution figures are valid for product version 2 and higher of the Piranha.

Waveform recording time

At max sampling rate

At min sampling rate

1024 ms (2 kSa/s)

524 s (4 Sa/s)

A total of 8 recording times are available, all separated by a factor of 2, i.e. 1, 2, 4, 8,

16, 33, 66, 131, 262 and 524 seconds.

The setting for

Waveform recording time

may affect the Irradiation time calculation. Make sure to set back the

Waveform recording time

to the lowest choice after temporarily modifying it. Please also note that in

QABrowser, the waveforms are limited to between 0.32 and 4 seconds.

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Hardware and Specifications

21

2.4.1.4

Typical Response, Piranha

The table below shows the typical response for the Piranha at standardised radiation qualities.

Radiography, Fluoroscopy, and Dental

(measured using RTI RQ Code R1, W/Al)

Radiation quality

PTB

DV40

DV50

DV60

DV70

DV80

DV90

DV100

DV120

DV150

ISO 4037

IEC 61267

RQR 2

RQR 3

RQR 4

RQR 5

RQR 6

RQR 7

RQR 8

RQR 9

RQR 10

Mean energy air kerma

(keV)

26,38

29,14

32,14

34,84

37,88

41,1

44,33

50,86

61,47

Total

Filtration

(mm Al)

2,49

2,46

2,68

2,83

2,99

3,18

3,36

3,73

4,38

Air kerma measurement

HVL

(mm Al)

1,42

1,77

2,19

2,57

3,01

3,48

3,96

5,00

6,55

Note

: These values are typical values measured at PTB in Germany in 2007.

Factor kQ

(Rel. RQR 5)

1,0186

0,9794

0,9949

1

0,9976

0,9920

0,9920

0,9988

1,0199

Radiation quality

PTB

DH50

DH60

DH70

DH80

DH90

DH100

DH120

DH150

ISO 4037

IEC 61267

RQA 3

RQA 4

RQA 5

RQA 6

RQA 7

RQA 8

RQA 9

RQA 10

Mean energy air kerma

(keV)

38,02

45,02

51,27

57,71

63,27

68,57

78,83

94,32

Total

Filtration

(mm Al)

12,5

18,7

23,8

29,0

33,2

37,4

43,7

49,4

Air kerma measurement

HVL (mm Al)

3,74

5,32

6,73

8,12

9,21

10,10

11,59

13,23

Note

: These values are typical values measured at PTB in Germany in 2009.

Factor kQ

(Rel. RQR 5)

0,9997

1,0021

1

1,0325

1,0309

1,0296

1,0191

1,0072

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Hardware and Specifications

Mammography, Mo / 30 µm Mo and 30 µm Mo + 2 mm Al

(measured using RTI RQ

Code M1)

Radiation quality

PTB

ISO 4037

IEC 61267

MMV25

MMV28

MMV30

MMV35

RQR-M1

RQR-M2

RQR-M3

RQR-M4

Mean energy air kerma (keV)

14,89

15,44

15,7

16,28

Air kerma measurement

HVL (mm Al)

Factor kQ

(Rel. RQR-M2)

0,28

0,31

0,33

0,37

0,9781

1

1,0073

1,0060

MMH25

MMH28

MMH30

MMH35

RQA-M1

RQA-M2

RQA-M3

RQA-M4

18,61

19,27

19,75

20,96

0,59

0,63

0,67

0,75

Note

: These values are typical values measured at PTB in Germany in 2007.

0,9840

0,9818

0,9744

0,9804

Mammography, Mo / 1 mm Al

(measured using RTI RQ Code M8)

Radiation quality

PTB

ISO 4037

IEC 61267

MAV25

MAV28

MAV30

MAV35

MAV40

-

-

-

-

-

Mean energy air kerma (keV)

17,58

18,29

18,66

19,36

19,89

Air kerma measurement

HVL (mm Al)

0,48

0,54

0,56

0,61

0,64

Note

: These values are typical values measured at PTB in Germany in 2009.

Factor kQ

(Rel. MAV28)

1,0033

1

0,9978

0,9944

0,9915

Mammography, Mo / 25 µm Rh

(measured using RTI RQ Code M3)

Radiation quality

PTB

ISO 4037

IEC 61267

MRV25

MRV28

MRV30

MRV35

MRV40

-

-

-

-

-

Mean energy air kerma (keV)

15,78

16,29

16,54

17,02

17,4

Air kerma measurement

HVL (mm Al)

0,34

0,38

0,39

0,43

0,45

Note

: These values are typical values measured at PTB in Germany in 2009.

Factor kQ

(Rel. MRV28)

0,9945

1

0,9980

0,9911

0,9852

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Hardware and Specifications

23

Mammography, Rh / 25 µm Rh

(measured using RTI RQ Code M4)

Radiation quality

PTB

ISO 4037

IEC 61267

RRV25

RRV28

RRV30

RRV35

RRV40

-

-

-

-

-

Mean energy air kerma (keV)

15,57

16,34

16,73

17,57

18,18

Air kerma measurement

HVL (mm Al)

0,32

0,37

0,39

0,45

0,49

Note

: These values are typical values measured at PTB in Germany in 2009.

Factor kQ

(Rel. RRV28)

1,0018

1

1,0036

1,0089

1,0081

Mammography, W / 0.5 mm Al

(measured using RTI RQ Code M7)

Radiation quality

PTB

ISO 4037

IEC 61267

WAV25

WAV28

WAV30

WAV35

WAV40

-

-

-

-

-

Mean energy air kerma (keV)

16,08

16,97

17,49

18,73

19,79

Air kerma measurement

HVL (mm Al)

0,35

0,40

0,43

0,51

0,58

Note

: These values are typical values measured at PTB in Germany in 2009.

Factor kQ

(Rel. WAV28)

0,9924

1

0,9974

0,9928

1,0028

Mammography, W / 50 µm Rh

(measured using RTI RQ Code M6)

Radiation quality

PTB

ISO 4037

IEC 61267

WRV25

WRV28

WRV30

WRV35

WRV40

-

-

-

-

-

Mean energy air kerma (keV)

17,6

17,99

18,19

18,78

19,54

Air kerma measurement

HVL (mm Al)

0,48

0,51

0,52

0,56

0,61

Note

: These values are typical values measured at PTB in Germany in 2009.

Factor kQ

(Rel. WRV28)

0,9978

1

1,0009

0,9969

0,9959

Mammography, W / 50 µm Ag

(measured using RTI RQ Code M10)

Radiation quality

PTB

ISO 4037

IEC 61267

WSV25

WSV28

WSV30

WSV35

WSV40

-

-

-

-

-

Mean energy air kerma (keV)

17,87

18,66

18,92

19,57

20,22

Air kerma measurement

HVL (mm Al)

0,50

0,56

0,58

0,63

0,68

Note

: These values are typical values measured at PTB in Germany in 2009.

Factor kQ

(Rel. WSV28)

1,0108

1

0,9983

0,9963

0,9969

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2. Description of the Piranha

Hardware and Specifications

2.4.1.5

Angular Sensitivity, Piranha

In this section you can see graphs of the typical angular sensitivity for dose measured with the Piranha at 28 and 70 kV. The setup is shown in figures below.

This "directional" behaviour makes it excellent for reproducible measurements, with less influence by nearby spreading matter. This makes it possible to make accurate HVL measurements even when measuring with "bad geometry", which is especially interesting for mammography. To understand, please see the polar plot shown below.

The Piranha is shown to the left, and a typical mammographic ion chamber to the right.

There are two different graphs, depending on the product version of your Piranha. The product version is the version number you can find on the label on the bottom of the

Piranha. If the version of your Piranha is 1.X, use the graphs marked v1. For 2.X and higher use graphs marked v2.

For v1.X it is however important that you place the detector surface perpendicular to the direction of the radiation source or that you make corrections according to the tables in section Corrections for Angular

Sensitivity

122

.

For radiography this is generally no problem, since most measurements are performed in the middle of the field, perpendicular to the incident radiation.

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Hardware and Specifications

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2. Description of the Piranha

Hardware and Specifications

2.4.2

Piranha External Probes

The inaccuracy is here defined as the root of the square sum of systematic errors, which has not been eliminated, and random errors (dispersion around a mean value).

The calculation of the inaccuracy is based on 15 different measurements and with a confidence level of 95 %. Of the total inaccuracy, random error is 20 % and general inaccuracy is 80 %.

Note

: Irradiation time is often called exposure time in daily use.

Reference conditions

Temperature

Relative humidity

Air pressure

Radiation quality

Radiography

Mammography

CT

+18 °C to +23 °C

50 %

101.3 kPa

70 kV, 2.5 mm Al

28 kV, 30 µm Mo

120 kV, 2.5 mm Al

Note:

The reference conditions are given in reference to the IEC61674 standard.

General

Connector type

Hirose ST40X-10S with built-in detector identification.

Measuring range and inaccuracy

The detector noise given is typical values at room temperature.

- Piranha External Dose Probe

(typical sensitivity +55 µC/Gy)

Parameter

Air kerma (Dose)

Air kerma rate

(Dose rate)

Range

100 pGy – 1.5 kGy

12 nR – 170 kR

4 nGy/s – 150 mGy/s

460 nR/s – 16 R/s

26 µR/min – 1000 R/ min

1.6 mR/h – 60 kR/h

Inaccuracy

±5 % (for time > 0.1 ms)

(valid for Irr. time >20 ms)

±5 % or ±1 nGy/s

±5 % or ±100 nR/s

±5 % or ±6 µR/min

±5 % or ±360 µR/h

Typ. noise

±500 pGy/s

(5 s moving average)

Irradiation time

±5 % or ±250 pGy/s

±100 pGy/s

1 nGy/s – 150 mGy/s

0.1 ms – 34000 s

1 – 65535 pulses

±1 % or ±0.5 ms

±1 pulse

Resolution

0.5 ms

Note 1

: The air kerma rate is calculated as the air kerma divided by the time. See also Waveforms and Triggers 82 .

Note 2

: The standard calibration for the Piranha External Dose Probe is W/23 mm Al. This calibration was chosen since the main use of the detector is to measure the dose to the image intensifier, after the phantom. However, you can just as well use this probe for measurements of skin dose. The detector is very linear in its energy response and will not be affected by a different filtration.

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Hardware and Specifications

27

Pulses

Parameter Range

Dose/pulse

Pulse dose rate

Min. output peak doserate

- High Sensitivity

- Low Sensitivity

Pulse rate

- Normally

Pulse width

Duty cycle

Minimum pulse width

1 nGy/pulse - 3 kGy/pulse

1

Lower limit 10 µGy/s (70 mR/min), otherwise same as for air kerma rate.

Doserate (min. pulse width)

0.23 µGy/s (4 ms) / 1.8 µGy/s (0.5 ms)

10 µGy/s (4 ms) / 73 µGy/s (0.5 ms)

0.5 – 100 Hz, resolution 0.5 Hz

4 ms - 2000 s

5 - 95 % pulse width (min. peak doserate)

4 ms (0.23 µGy/s) / 0.5 ms (1.8 µGy/s)

50 %

Minimum ripple

(pulse top to bottom)

Irradiation time

1 – 65535 pulses, resolution 1 pulse

Note 1

: Max dose/pulse depends on the pulse length.

Waveform recording time

At max sampling rate

At min sampling rate

1024 ms (2 kSa/s)

524 s (4 Sa/s)

A total of 8 recording times are available, all separated by a factor of 2, i.e. 1, 2, 4, 8,

16, 33, 66, 131, 262 and 524 seconds.

The setting for

Waveform recording time

may affect the Irradiation time calculation. Make sure to set back the

Waveform recording time

to the lowest choice after temporarily modifying it. Please also note that in

QABrowser, the waveforms are limited to between 0.32 and 4 seconds.

The table below shows the typical response for the Piranha External Dose Probe at standardised radiation qualities.

DV40

DV50

DV60

DV70

DV80

DV90

DV100

DV120

DV150

Radiation quality

PTB

ISO 4037

IEC 61267

RQR 2

RQR 3

RQR 4

RQR 5

RQR 6

RQR 7

RQR 8

RQR 9

RQR 10

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Mean energy air kerma

(keV)

26,38

29,0

32,0

34,8

37,8

41,0

44,2

50,8

61,2

Total

Filtration

(mm Al)

2,49

2,46

2,68

2,83

2,99

3,18

3,36

3,73

4,38

Air kerma measurement

HVL

(mm Al)

1,42

1,77

2,19

2,57

3,01

3,48

3,96

5,00

6,55

Factor kQ

(Rel. RQR 5)

1,087

1,044

1,013

1

0,993

0,988

0,986

0,986

1,002

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2. Description of the Piranha

Hardware and Specifications

Note

: Note: These values are typical values measured at PTB in Germany in 2009.

- Piranha MAS-1 Probe, Invasive mAs probe

(sensitivity 1 nC/mAs)

Module type

Tube charge

Tube current

Pulse tube current

Range

0.001 mAs –

0.1 – 3000 mA

Lower limit 1 mA, otherwise same as tube current.

0.1 ms – 34000 s

1 – 65535 pulses

Inaccuracy

±1 % (for time > 0.1 ms)

Typ. noise

±1 % or ±10 µA (for time >100 ms) ±1.5 µA

Time

1

±1 % or ±0.5 ms

±1 pulse

Resolution

0.5 ms

Note 1

: When the Piranha internal detector is used simultaneously, the default mode of operation is to use the internal detector for time measurement.

Note 2

: The tube current is calculated as the tube charge divided by the time. See also Waveforms and Triggers

82

.

- Piranha MAS-2 Probe, Non-invasive mAs probe

(sensitivity 1 nC/mAs)

Typ. noise Module type

Tube charge

Tube current

Pulse tube current

Time

1

Range Inaccuracy

0.1 mAs – ±5 % (for time > 0.1 ms)

10 – 4000 mA ±5 % or ±2 mA (for time > 20 ms)

(±3 % at 250 mA)

Lower limit 50 mA, otherwise same as tube current.

0.1 ms – 34000 s

1 – 65535 pulses

±1 % or ±0.5 ms

±1 pulse

Note 1

: See also note 1 and 2 for the Piranha MAS-1.

±1 mA

Resolution

0.5 ms

- Piranha Light Probe, Light detector

(typical sensitivity 670 pA/nit or 200 pA/lx)

Module type

Luminance

Illuminance

Range

0.003 – 72000 cd/m²

0.001 – 24000 lx

Inaccuracy

±5 % or ±0.6 mcd/m²

±5 % or ±0.2 mlx

Typ. noise

±0.3 mcd/m²

±0.1 mlx

- CT-DP, CT Dose Profiler

(typical sensitivity 3.6 µC/Gym)

Module type

Air kerma (Dose)

Air kerma rate

(Dose rate)

Range

1,5 nGy – 22 kGy

160 nR – 2.5 MR

60 nGy/s – 1.1 Gy/s

6.8 µR/s – 125 R/s

0.4 mR/min – 7500 R/min

24 mR/h – 450 kR/h

Inaccuracy

±5 %

±5 %

±5 % or ±15 nGy/s

±5 % or ±1.6 µR/s

±5 % or ±0.1 mR/min

±5 % or ±6 mR/h

Typ. noise

±8 nGy/s

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Standards and Compliances

29

2.5

Standards and Compliances

Hereafter you can find declarations of conformity, as well as documents describing the intended use of the Piranha system.

2.5.1

Waste Electrical and Electronic Equipment (WEEE)

The European Union Directive 2002/96/EC on Waste from Electrical and Electronic

Equipment (WEEE) places an obligation on manufacturers, distributors, and retailers to take back electronics products at the end of their useful life.

The WEEE directive covers all RTI products being sold into the European Union (EU) as of August 13, 2005. Manufacturers, distributors, and retailers are obliged to finance the cost of recovery from municipal collection points, reuse, and recycling of specified percentages per the WEEE requirements.

Instructions for disposal of WEEE by Users in the European Union

The symbol, shown left, is marked on the product, which indicates that this product must not be disposed of with other waste. Instead, it is the user's responsibility to dispose of the user's waste equipment by handing it over to a designated collection point for the recycling of waste electrical and electronic equipment. The separate collection and recycling of waste equipment at the time of disposal will help to conserve natural resources and ensure that it is recycled in a manner that protects human health and the environment. For more information about where you can drop off your waste equipment for recycling, please contact your local distributor from whom you purchased the product.

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2.5.2

2. Description of the Piranha

Standards and Compliances

Manufacturer's Declaration of Conformity

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2.5.3

Intended Use

2. Description of the Piranha

Standards and Compliances

31

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2. Description of the Piranha

Standards and Compliances

2.5.4

FCC Certification

Piranhas of product version 3.1 and newer contains FCC certified transmitter module

(Bluetooth).

FCC ID R47F2M03GX

This device has been tested and found to comply with the limits for a Class-B digital device, pursuant to part 15 of the FCC rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in commercial environment. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used according with the instruction manual, may cause harmful interference to radio communication. Operation of this equipment in a residential area is likely to cause harmful interference, in which case the user will be required to correct the interference at his own expense.

2.6

Maintenance

2.6.1

Updating the Piranha Firmware

All firmware that is controlling the function of the Piranha is stored in flash memory to allow quick and easy update. The RTI Updater with the latest firmware is always available free of charge on the RTI Electronics Web site at http://www.rti.se

. To update your Piranha you must first download the latest version and install it on a PC. The PC needs to have an USB port.

You will need to have access to an administrative account to install the software.

To update the Piranha firmware (or bootloader):

1. First download the latest version of the RTI Updater Setup from RTI Electronics Web site.

2. Unzip the file and run the file "RTI Updater Setup.exe" to install it on your PC. In the end of the installation process you will get the question if you want to run that updater immediately. If you have your Piranha available you can connect it as described in step #3. Answer "Yes" and continue with step #6.

3. Connect the Piranha. Use the USB cable that came with your Piranha to connect your

Piranha to one of the USB ports on the PC. Power on the Piranha. Use the power supply to ensure that no power failure occur during the update process. If you do not have a power supply available, make sure you have fresh batteries in the Piranha.

You will get a notice about that.

4. Go to

Start Menu | RTI Electronics | RTI Updater

and select the RTI Updater.

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33

5. The RTI Updater starts and locates the Piranha automatically if it is connected to an

USB port.

6. If the Piranha is found, the window in the figure above is shown. The different modules are checked and after a while the start button is enabled. Click

Start

. If the

Piranha cannot be found, a message with suggested solutions is shown.

7. The updating process starts. The RTI Updater checks the current versions and compares with the update. Modules with old firmware are automatically updated.

8. Note that storing the new firmware in the flash memory may take several minutes for each module. The RTI Updater will indicate which modules have been updated.

9. Power off the Piranha and disconnect the serial cable when the program indicates that everything is OK.

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Maintenance

If you have any problem with your Piranha after updating, re-install the firmware again before contacting your local distributor or RTI Electronics. To re-install firmware repeat step 1 to 9 above, but before performing step #6 go to the menu

Settings

and select

Always Overwrite

.

If you want to see more details of what is updated, use the menu

Settings

- Advanced

, and you will see more information as shown in the figure below.

You normally also need to update the QABrowser and Ocean, when you update the firmware. See section Updating the QABrowser 70 and the

Ocean manual for details.

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35

2.6.2

Managing Detector Calibrations

RTI Detector Manager

is a special Windows software that gives an overview of all calibrations for the detectors and probes in your system. You will find the RTI Detector

Manager on your Product CD, in the folder

\Software\RTI Detector Manager\.

,Start the file

RTI Detector Manager.exe

by double-clicking it.

Select the instrument of interest (Piranha) and click

OK

.

If no instrument appears, check the communication cable and that the Piranha is powered on, then click

Rescan

.

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Next, the available detectors are shown to the left. The

Internal detector is always available, but external probes will only show up if they are attached.

When clicking a detector, the available calibrations will show up to the right (In this case the Internal detector is highlighted). The TV and TF columns show an

×

if there are calibrations for Tube

Voltage and/or Total

Filtration. The factor column shows the calibration factor

(for dose in this case).

Here is another example

(Piranha Dose Probe). This type of detector only contains a calibration factor for dose.

Piranha & QABrowser Reference Manual

Chapter 3

Description of the

QABrowser

3. Description of the QABrowser

Introduction to the QABrowser

3 Description of the QABrowser

37

3.1

Introduction to the QABrowser

The QABrowser is a program that runs on a handheld computer. It will quickly guide you through the measurements and tests of different X-ray systems. The QABrowser controls the Piranha and provides an intuitive user-interface. The instrument is set-up based on the type of measurement you select. Two main measuring modes are available; real-time display (RTD) and application mode.

In real-time display mode "virtual" meters are shown allowing you to read real-time data.

Up to six values can be measured and displayed at the same time. The built-in applications allow you to do different tests such as accuracy, reproducibility, linearity,

HVL, and CTDI. There are also applications for viewbox test and monitor test using the light detector. The QABrowser also allow you to look at waveforms and log data.

The text in this section assumes that you purchased your Handheld Display either directly from RTI or a RTI dealer, which means that QABrowser is already installed and configured on the Handheld Display. If you have purchased your handheld on your own, then you first need to install the QABrowser to the handheld. How to do this for Palm OS handhelds is described in the installation chapter in the HTML Help file on your Product

CD.

3.2

Starting the QABrowser

Wireless through Bluetooth

1. Turn on the meter.

2. Launch the QABrowser by tapping on the QABrowser icon.

Please note that

All

needs to be selected at the top of the screen for the QABrowser icon to be visible.

3. The handheld will now search for available Bluetooth devices and show them to you.

4. Select your meter and press OK.

5. If prompted enter the passkey for the meter which is “0000”.

If you experience any problems connecting through Bluetooth please see the

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3. Description of the QABrowser

Starting the QABrowser

troubleshooting

154

chapter , or visit the RTI website for more information.

3.3

Real-time Display and Waveforms

This section will show how to make a measurement with the Piranha and the

QABrowser. It is illustrated with an example using a radiographic X-ray unit. The operation of the QABrowser has a general structure and the described procedures applies also to other modalities. You can also follow this example using a mammography or a dental system. You must then of course make the appropriate selections of X-ray systems and your screen might look different from the screens shown in this manual. However, you will be able to learn and follow the workflow of the

QABrowser. You will find specific information on how to perform different types of measurements in the Measurements section.

Set up the Piranha as described in topic Setting Up the Piranha

12

.

3.3.1

Using the Real-Time Display

There are two main measuring modes;

Real-Time Display

(RTD) and

Applications

in the QABrowser. We will first see how to use the RTD to measure different parameters and viewing waveforms. Earlier in the topic Setting Up the Piranha

12

was showed how to set up the Piranha system and how to start the QABrowser.

1. A list with different type of measurements is shown.

Note that the number of items in the list is depending on the configuration of your Piranha system. Your list may have other choices than the list shown here. To view items not visible, tap the arrow or use the scroll button on the handheld computer.

For this example, select

Radiography

.

2. A list with all different parameters are shown. You can select to measure a single parameter or all at the same time. In this example select

All

.

Note that the parameters shown here, are the ones that are available with the current configuration of your system, including attached probes. For instance must your MAS probe be attached for the mAs parameter to be shown.

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39

3. If you had chosen Dose earlier, and you have a

Piranha model that supports external dose measurements you must select the detector you want to use. If you want to measure dose with the external probe tap

External

, otherwise tap

Internal

.

4. The

Real-Time Display

(RTD) is now shown and you are ready to measure, see figure below. The Piranha is set to the most suitable settings for the selected type of measurement, in this case radiography. The selected kV-range is 45-125 and the radiation quality is W/3mm Al (reference radiation quality). Depending on type of measurement, you may have several kV-ranges and beam qualities to choose from.

For radiography, you have three different kV-ranges (35-75, 45-125, and 90-155) to select between.You will have four displays on this screen if you do not have/use a mAs-probe and six if you selected to measure mAs. The manual for the mAs-probe explains how to connect it.

Here measurement indicators are shown.

Change unit by tapping the unit text

Change kVrange by tapping here

Change Radiation Quality by tapping here

Tap here to reset detectors

When you tap a unit, a list to select unit from is shown. Tap the desired unit or tap

Cancel

to keep the present one.

The first thing to do before starting to measure, is to verify that the Piranha internal detector is placed correctly in the X-ray field. A special function is available to do this.

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Real-time Display and Waveforms

Position the Piranha under the tube as described in the topic Setting Up the Piranha

12

.

The

Position Check

is usually not necessary for Radiography, but often essential for the other modalities, in order to get more accurate measurements. To skip go to 8.

5. Tap the kV-range selector, and a list will appear, as shown left. Tap

Check[C]

to select the Piranha position check.

6. The

Position Check

screen is now shown. Set up the X-ray generator. Recommended kV is:

Radiography: use 70 kV

Mammography: use 28 kV

CT: use 120 kV (or any other available kV setting).

7. Make an exposure. A message will be shown. If the detector is incorrectly aligned, the QABrowser will tell you to re-position the detector. For a small misalignment a correction factor is applied and you are allowed to continue without re-positioning the detector. This message disappears automatically if the position is OK.

If the displayed number is between 0.950 and 1.050 the position is acceptable and a correction factor will be applied to correct the position to "1.000". The correction factor is valid until you perform this check again or until you quit the QABrowser. It is recommended to perform the position check after any repositioning of the detector or after change of target/filter combination when measuring on a mammography unit.

You are now ready to make the first exposure. Set the generator to 80 kV. Make sure that the correct kV range is used, in this case "R1[4] 45-125". When you make the first exposure, the Piranha will evaluate what kind of waveform it is (DC/HF, 3-phase/12p, 3phase/6p, or 1-phase) and the total filtration. This is done for all measurement types but

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mammography. Default values are "DC/HF" and 3.0 mm Al.

8. Make an exposure. Every time the Piranha recognizes an exposure the RTI logo is superimposed on screen for a short while.

41

The Piranha analyses the waveform and shows the result automatically after the first exposure. If the result is incorrect the actual waveform type needs to be set manually, see topic Settings

43

for more information.

The Piranha measures the total filtration for each exposure (for all measurement types except mammography). It is shown automatically after the first exposure.

If you want the QABrowser to lock this value and not estimate it again for the following exposures, tap

Keep

. You can also enter the total filtration manually under the settings, see topic Settings

43

for more information.

Up to six values can be shown simultaneously.

Measured kVp, dose, and dose rate values are compensated depending on actual total filtration

(between 1.5 - 38 mm Al) and waveform type.

The display looks different depending on the type of parameter you selected in step

#3 and if you are using a mAs probe or not. In the pictures below you can see how the screen looks if you do not measure mAs and if you select just

Tube voltage

.

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Real-time Display and Waveforms

The single parameter displays are large to allow reading from distance. In the single parameter displays complementary values may be shown (in the figure above exposure time and total filtration). Which complementary values that are shown depends on the selected parameter. Up to three complementary values can be shown.

If any of the displayed values is not possible to compensate or cannot be measured with full accuracy the symbol is displayed at the top of screen. If the symbol is displayed you can tap it with the pen to display more information.

3.3.2

Waveforms - Acquiring and Viewing

Waveforms are always captured for each exposure you make. Up to three waveforms are simultaneously captured and visualized with the QABrowser. The following waveforms can be measured depending on configuration and selected type of measurement: tube voltage (kVp) with the Internal detector dose rate with the Internal detector dose rate with the external Dose Probe (available for specific Piranha models).

tube current (mA) with the external Dose Probe (available for specific Piranha models).

In Continuous update mode you also have the possibility to restart the waveform collection during the measurement. Every time you tap

Hold

, the waveforms are acquired again. When you do this, the previously acquired waveforms will be replaced.

The waveforms available for viewing will be the ones from you last

Hold

tap.

To view waveforms after the exposure:

1. Tap

Wave

(or press the corresponding button). The waveform screen appears and waveforms are displayed. The kV waveform takes a few seconds to calculate before it is displayed.

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2. The waveforms are displayed and you can use the pen to move the cursor. Corresponding cursor values are shown under the waveforms.

3. Tap

kVp

,

Dose…

,

or

mA

once to hide/show the corresponding waveform.

43

4. You can now make new exposures without returning to the real-time display. The old waveforms are then erased, and the new ones are shown. If the

waveform recording time

is much longer than the exposure time, you may only get a part of the waveform, since the Piranha is still capturing the waveform. Then you can go back to the RTD and tap

Wave

again, when the

waveform recording time

has passed, to get the full waveform

.

3.3.3

Measurement Settings

As mentioned before all settings of the Piranha are done automatically when you select type of measurement. For example, when you choose fluoroscopy the detector sensitivity is set to high. However, there might be situations where the default settings cannot be used and settings must be adjusted. Use

Settings

to adjust the Piranha when necessary. The figure below shows how to access this function.

Tap this symbol to open the screen with

Settings

for the Piranha and the various detectors

When you tap the symbol the

Settings

screen is shown. This can also be accomplished by tapping the icon on the graffiti area (or the Tungsten T3, T5, TX status bar). What is shown here is dependent on selected parameter(s) and used detectors.

Conditions

Shows general conditions for the measurement. Different values can be shown depending on selected measured parameter. Details about the Condition screens can be seen in Settings - Conditions

45

.

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Tap

Conditions

to show the drop-down list with other settings:

Piranha

: General settings for the Piranha.

Internal detector detector

: Specific settings for the

Internal detector detector

.

If your model of Piranha has an external probe that is attached it will also show here.

Piranha

Shows general settings for the Piranha. You can find information about the different parameters in Settings -

Piranha

48

.

Internal detector

Shows specific settings for the Internal detector detector as well as the serial number.

You can find information about the different parameters in Settings - Internal detector

50

.

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45

MAS-2

Shows specific settings and the serial number for the detector that is connected to the external connector. In this case it is a MAS-2 probe.

You can find information about the different parameters in Settings - Other Detectors 52 .

Default values for the settings are depending on the selected type of measurement and detector.

Tap

Back

to return to the real-time display.

3.3.3.1

Settings - Conditions

Here general conditions for the measurements are shown. Different values can be shown depending on selected measured parameter.

Conditions - TF and Waveform

These are parameters of the X-ray generator which influence the measurements. The Piranha can measure these, or you can set them yourself.

Total Filtr.

Waveform

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Shows actual total filtration value.

Estimate

means that a new estimation will be performed at next exposure and the values will be displayed on screen.

Shows the actual waveform type. Determine means that a new analyse of the waveform will be performed for the next exposure. The result will be displayed on screen. The waveform types supported are:

- DC/HF

- Single Phase

- 3-Phase 6-Pulse

- 3-Phase 12-Pulse

- AMX-4

- Pulsed

The first four can be automatically determined when

Estimate

is chosen. The selected or set waveform is also shown with a symbol

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Real-time Display and Waveforms

on the Real-Time Display, see Indicators and Symbols

68

.

AMX-4

The difficulties when measuring tube voltage on a GE AMX-4 is a well-known problem.

Due to high kV ripple at a frequency of 2 kHz it is hard for most non-invasive kVpmeters to follow the kV waveform correctly.

This waveform type has an agreement with measurements made with the Keithley Triad

System 37946C mobile filter pack (50-135 kV), which is the only filter package recommended by GE. According to GE, the use of the standard Keithley 37617C W-R filter pack (50-150 kV) is not good enough. The results have further been verified with measurements with a traceable high voltage divider that has sufficient bandwidth to accurately follow the kV ripple from the AMX-4.

Therefore it is important to select the

AMX-4

waveform under

Settings | Conditions

.

More about the AMX-4 correction can be found in the

Application Note 1-AN-52020-1 from RTI Electronics

AB.

Pulsed

This waveform type should be used for pulsed fluoroscopy especially when the pulses do not have a "good" square waveform shape. The exposure time must be longer than the selected recording time when using this waveform type. Pulsed waveform type is selected under

Settings | Conditions

in the same way as the AMX-4 waveform type.

Conditions - Pulse rate

Conditions - Pulse rate

If a pulsed mode is used, like pulsed fluoroscopy or pulsed radiography (cine) the pulse rate can be specified in pulses per second (same as Hz). This allows you to get a dose/pulse reading even if the detector used (e.g. ion chamber) is too slow for the

Piranha electrometer to detect the pulses. A solid-state detector, like the Piranha Dose Probe, is however fast enough to detect the frequency even for very low-level signals.

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Conditions - Compression paddle

For mammography, it is sometimes easier to do measurements with the compression paddle in the field.

The compression paddle will however normally affect the Piranha kV and dose reading. With this check box, all the measured values (kV, dose and HVL) will be corrected according to what the user has selected. The default setting the first time you start the software is without the compression paddle in the field.

When selected you will see the settings for

Scatter factor

and

Equivalent thickness

. The thickness is given in mm Al, if you do not know, ask the manufacturer or make a comparison with Aluminium filters. When this option is active, an indicator on the RTD screen indicates that this feature is on.

Scatter factor

If an ion chamber is positioned just below the compression paddle, the measured dose will rise, because of side scattering from the compression paddle material. The effect of this is depending on the ion chambers angular dependence. Since the Piranha is almost insensitive to this, you can put a number here to compare readings from the Piranha with readings from an ion chamber.

See also section Average Glandular Dose, AGD (MGD)

123

.

When this is activated a red compression paddle indicator will show in the top right corner of the RTD screen ( ).

Equiv. thickness

The given equivalent compression paddle thickness is used to increase the accuracy of dose measurements when dose is measured below the compression paddle. It is given in equivalent thickness of aluminium.

This feature can also be used if you have additional filtration in the beam. Add the equivalent thickness of aluminium.

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Conditions - Beam Correction

Sometimes you may want to make comparable measurements with known mechanical setup. For instance if you want to emulate ion chamber measurements in a particular scattering situation. Then you can set a

Beam Correction factor

to get that reading. In this case the ion chamber measures an extra

25 % from side and back-scatter. Using this factor makes the readings to be the same. It is of course important that the mechanical setup in these cases are the same. When this function is activated a red horisontal indicator will show in the top right corner of the RTD screen ( ).

Here you can see an example of a holder that is used for some customers to replace ion chambers in ready-made fixtures.

3.3.3.2

Settings - Piranha

Here general measurement settings for the Piranha are shown.

Post Delay

The post delay time defines how long time the Piranha shall wait and "look for more" after detecting what can be considered to be

"the end of the exposure". Default value is 250 ms. The post-delay is necessary when measuring on units with some kind of pre-pulse or for pulsed exposures.

The post delay can be set to:

Off, 25 ms, 250 ms, 1 s,

or

Other…

(0-9999 ms).

The default value is set according to selected type of measurement, see section Measurement Type Settings

74

.

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49

Trig source

This setting makes it possible to define the trig source for the electrometer module.

Available settings are:

Individually

, each detector starts to measure individually when it detects a signal.

Internal detector

, the measurement of all parameters (all modules) start when the Internal detector starts to measure.

Default value is always Internal detector when it is used. This is the recommended trig source.

Trig level (time)

Here you can set the level used for irradiation time measurements.

"Trig level (time)" (TL) is normally set to 50 % of the peak waveform (S

PEAK

), but can be set between 10 and 90 %. The irradiation time is then calculated as the end time minus the start time.

The start time is the first time the signal goes above TL×S

PEAK

.

The end time is the last time the signal goes below TL×S

PEAK

.

See example below.

Update

2014-06/5.5C

This setting defines when Piranha shall send measured values to the QABrowser.

Four different alternatives are available:

After exp

., the QABrowser receives a new value when the exposure terminates.

Continuous

, the Piranha is continuously sending data as long as radiation is detected. Displays in the

QABrowser are updated about every four seconds.

Typically used for Fluoroscopy.

Timed

, the user sets a measurement time. The user then starts the measurement and the Piranha will measure all radiation received during the measurement time, without any trig levels. When the time has passed, a reading will be presented.

Free run

, the Piranha will continuously measure the radiation without any trig levels.

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Waveform rec. time

Default value is set according to selected type of measurement and this parameter normally never needs to be manually changed, unless really low-level measurements are to be accomplished. See the sections Measurement Type Settings

74

and Update

Modes 75 for more information.

The QABrowser is able to show a total of 640 samples.

The sampling interval is normally 0.5 ms, giving a total measurement window of 320 ms. By increasing the sampling interval, a sampling window up to 40 seconds, or even more, can however be selected. This is very handy when longer exposure times are used and the waveforms need to be viewed.

See section Update Modes

75

for more information. The default value is set according to selected type of measurement, see section Measurement Type Settings

74

.

Start after delay

When this is selected, the waveform recoding will start after the set delay. This can be useful if you want to study a phenomenon that occurs after the normal waveform recording time. When this is selected the electrometer waveform will not show simultaneously and you will get a warning that the irradiation time measurement is inaccurate. The reason for this is that the Piranha needs the waveform from start to be able to accurately calculate the irradiation time.

This is a temporary setting, and it will be turned off when you exit the RTD.

3.3.3.3

Settings - Internal detector

Here general measurement settings for the Internal detector are shown. You can find information about the different parameters below.

-

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51

If

Normalize to distance

is checked, another section is shown. See description below.

Sensitivity

Dose/TF

This is used to set the dose and TF sensitivity for the Internal detector.

The sensitivity can be set to: Low, High, and Very High.

Default value is set according to type of measurement.

Sensitivity kV

This is used to set the kV sensitivity for the Internal detector.

The sensitivity can be set to: Low and High.

Default value is set according to type of measurement selected.

Delay

Window

Normalize to distance

The delay time defines how long time the Piranha shall wait before starting to measure kVp after that radiation has been detected.

The delay can be set to: Off, 5 ms, 25 ms, 100 ms, 500 ms, 1 s, 2 s, or Other…(0-9999 ms)

The default value is set according to selected type of measurement, see section Measurement Type Settings

74

.

This gives the possibility to define a fixed time that Piranha measures kVp after that the delay time has expired.

The window can be set to: Infinite, 5 ms, 10 ms, 25 ms, 100 ms,

200 ms, or Other…(0-9999 ms)

Default value is always "Infinite".

If Normalize to distance is checked, you have the option to normalize the dose reading to any given distance. Here you can enter your

Source to Detector Distance (SDD) and a normalizing distance (SDD

Norm), that you want the dose normalized to. When this is activated a blue

N

will show in the top right corner of the RTD screen.

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3.3.3.4

Settings - Other Detectors

Here general measurement settings for other detectors or probes are shown. You can also see the detector's serial number. Note that different detectors have different options.

Sensitivity

This is used to set the sensitivity for the electrometer module. The sensitivity can be set to:

Low

and

High

.

Default value is set according to selected type of measurement and used detector.

Threshold

This is used to set the trig level. It can be set to

Low (½×)

,

Normal, 2×

,

, and

. The default value is "Normal". The setting "Low" can be used if low signals are measured and a lower trig level is required.

However, the risk for false triggering increases when "Low" is used. To avoid false triggering in a noisy environment use one of the "higher" threshold levels.

Normalize to distance

Note: Only for dose detectors!

If

Normalize to distance

is checked, you have the option to normalize the dose reading to any given distance. Here you can enter your

Source to Detector Distance (SDD) and a normalizing distance (SDD

Norm), that you want the dose normalized to. When this is activated an "N" symbol will show on the RTD screen.

3.4

QABrowser Applications

There are several built-in applications available to simplify different standard QA tests.

Some applications are general and are available for many types of measurements and parameter selections, while other are very specific for a certain parameter. Applications can be used to analyse one or several parameters at the same time.

The first example shows how the accuracy of kVp can be tested using the built-in application

Accuracy

. The second example shows a multi-parameter

Accuracy

application.

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3. Description of the QABrowser

QABrowser Applications

The Accuracy Application (single-parameter)

1. Go to the real-time display that displays only kVp. Tap

Appl

or press the corresponding button to open the application list.

It is recommended to make one exposure first to analyse the waveform and estimate the total filtration.

53

2. The Select application screen lists the available applications for selected Type of measurement and Selected parameter.

For kVp, only

Accuracy

and

Reproducibility

are available.

Choose

Accuracy

by tapping it with the pen. You can also use the scroll button to highlight Accuracy and then press the button that corresponds to

Select

(the right-most button).

3. The accuracy application is shown on the screen. The set values (for kVp) are stored in a Set-value list. You can modify the list or individual values.

To modify an individual set value tap with the pen on it. In this case tap

60

.

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3. Description of the QABrowser

QABrowser Applications

4. An input box is shown at the bottom of the screen allowing input of a new set value.

Enter a new value using the pen on the graffiti area, then tap

OK

.

Tap

Cancel

to leave without modifying the set value.

If you want to, edit or view the complete set value list. Then tap , at the top of the screen, or the Menu icon (the lower icon to the left of the graffiti area) and select

Options | Edit Set Value List

from the pulldown menu.

You can now change/delete/insert values in the set value list for current application. Use the graffiti area to enter new values.

Tap

OK

to save changes or

Cancel

to return to the application without changing the list.

5. Make exposures according to the set values. Measured values are shown and the inaccuracy of kVp is calculated and displayed for each exposure. You can always tap a previous row and redo that exposure. Number of exposures and maximum inaccuracy is shown at the lower part of the screen. Tap

Graph

to show result in a graph.

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QABrowser Applications

The result is plotted in a graph together with the maximum and minimum accepted limits

(dotted lines) for the tested parameter. The limits are defined in the

Setup

, see topic

QABrowser Setup/Regulations

64

for more information. You can use the pen or buttons to move the cursor to view result for individual points.

55

3.4.2

The Accuracy Application (multi-parameter)

It is also possible to test several parameters at the same time. As an example

Radiography/All/Accuracy

is used.

1. Tap

Appl

to activate the application screen.

2. Available applications for Radiography/All are shown. Choose

Accuracy

by tapping it with the pen. You can also use the scroll button to highlight

Accuracy

and then press the button that corresponds to

Select

(the right-most button).

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3. Description of the QABrowser

QABrowser Applications

3. The multi-parameter application is shown.

In this mode only one exposure at a time is shown on the screen. You can here also change individual set values or the complete list for a specific parameter.

To modify an individual set value tap with the pen on it. In this case tap

60

.

4. An input box is shown at the bottom of the screen allowing input of a new set value.

Enter a new value using the pen on the graffiti area, then tap

OK

.

Tap

Cancel

to leave without modifying the set value.

If you want to, edit or view the complete set value list. Then tap , at the top of the screen, or the Menu icon (the lower icon to the left of the graffiti area) and select

Options | Edit Set Value List

from the pulldown menu.

You can now change/delete/insert values in the set value list for current application. Use the graffiti area to enter new values.

Tap

OK

to save changes or

Cancel

to return to the application without changing the list.

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QABrowser Applications

5. Set the generator according to the set values. Make an exposure.

57

Measured and calculated values are shown for two seconds before the set values for the next exposure is shown. Make all exposures in the list. You can always go back to previous exposures by tapping the arrow symbols . You can at any time go back and redo a previous exposure.

6. Perform all exposures in the list.

7. You can look at the result graphically for each parameter tested. Highlight a parameter by tapping it with the pen (not the set value) and then tap

Graph

or press the corresponding button. The accuracy limits (dotted lines) in the graph are defined in the QABrowser Setup, see topic QABrowser Setup/Regulations 64 .

3.5

Data Logging

The QABrowser can log data and save data in files on the handheld computer.

Prepare the data log by first entering some basic information about the measurement.

Open the pull-down menu and select

Setup

or go to the

Start Screen

and tap

Setup

.

From the Setup menu select

Log

.

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3. Description of the QABrowser

Data Logging

The first thing to do is to start a log session. This is done from

Options | Start Log

on the pull-down menu. You open the pull-down menu by tapping or by tapping the

Menu icon

to the left of the graffiti area. Activate the log by tapping

Start

Log

. You will now be asked to enter a

Log Note

. This can be some kind of information that you want to save in the log file. Continue with

OK

or

Don't Show

if you do not want to save a note.

The log is now activated and the result of each exposure is being saved in the log file.

The active log is indicated with the animated black symbol at the top of the screen. This symbol is in motion as long as the data saved in the log file. Now make some exposures at some different kV stations.

In

After exposure

or

Timed

update modes a value will be written to the log file each time the exposure indication is shown. For

Continuous

update mode a value will be stored each time you tap the

Hold

button. In applications, the log values are stored when you exit the application. This means that you can start the log after you have done your measurements and still get all data to the log.

If you want to pause the log temporarily just select

Options | Pause Log

on the pulldown menu. The log is still active but no data is saved in the file (the log indication

"freezes"). This makes it possible to make exposures that are not saved in the log file.

To resume data logging (into the same file) select

Options

|

Pause Log

again. If you got bad reading, you can also use the pull-down menu time

Options

|

Delete Last Logged Value

to delete single values from the log.

Note that when measuring in an Application

,

the data will not be stored in the log file until you exit the Application. That means that even if you start the log after you have begun measuring you will still get all the application measurements in the log file.

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Data Logging

59

You can stop and save the log from the pull-down menu by selecting

Options

|

Save Log

.

The contents of the log file is displayed. You can now:

Export

(only

PalmOS)

Export the log file to Memo Pad (a standard application in your handheld). Read the manual for the handheld computer to get more information about the Memo Pad.

Delete

Delete log file.

3.6

Favourites

From the beginning we sought to make the menu structure of the QABrowser very intuitive and simple to use. For a new user it is very simple to go step-by-step and perform a measurement and at the same time learn how the QABrowser works.

However, once you become familiar with the interface, and find yourselves performing the same types of measurements over and over again, you may desire to move between these types of measurements more quickly. Instead of going up and down through the menu trees we found that users would like to move across the tree structure. The desire was to find a solution for this need but still be able to keep the simplicity and intuitiveness of the existing menu structure. The solution to this is a feature called "Favourites". We will recognise this term from the web browsers. This is how it works:

When you find a specific RTD or application for a specific type of measurement that you perform on a regular basis you can add it to the Favourites list.

You may give the Favourite a title or use the one suggested by the QABrowser.

If you instead select

Start Here!

, a special Favourite will be created, that gets you right back to this test, the next time you start the QABrowser.

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3. Description of the QABrowser

Favourites

Favourites are saved in a list under different groups.

Different groups are created with specific names identifying those groups and then favourites are saved within those groups. You then selects one of the favourites from the list depending on what they intend to measure with the Piranha. For the next measurement

You may select another favourite from the list.

If you have any favourites saved, the QABrowser will always start with the Favourites screen.

When a specific type of measurement is saved in the favourites list all the important settings such as measuring mode, delay, window, post delay, sensitivity, detector type, measuring units, and much more are saved with it. If you save an application, for example "Accuracy", even the set value list is saved. That is, both an "Accuracy" table for a Siemens generator with specific set values as well as another "Accuracy" specific for a GE generator can be saved. When either of these new Favourites is selected you will have all the proper set values without having to change anything.

The "Favourites" list is also always accessible from anywhere in the program in the drop/down menu or by tapping the

"House" icon found on the Graffiti Pad.

The "House" icon on the Palm Tungsten T3,

T5, TX status bar can also be used.

.

3.6.1

Getting Started with Favourites

A smooth way to save time and quickly get started with the measurements with the

QABrowser, is by saving the settings as a favourite. Next time you do the same kind of measurement you just open the favourite and start with the measurements.

Saving a Favourite

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Favourites

61

To save a favourite you have to be in RTD (realtime-display), as shown to the left. Then tap the blue menu field, in the upper left corner. The menu will be shown. Choose

Options | Add to

Favourites...

.

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The favourite must be saved in a group and a new group is created by tapping

New...

.

Creating a group, so that the favourite can be saved in this.

Saving a favourite in a certain group (

Mammo

in this case).

The saved favourites can be found in the menu field, tap

Options

and then

Favourites...

.

To start the favourite that you are interested of, you have to mark the favourite and then tap

Select

, in the bottom right corner.

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3. Description of the QABrowser

Favourites

Deleting a Favourite or Group

When you want to delete a favourite or a group, you have to be in the

Favourites

window and then choose

Edit

in the menu. You can choose if you want to delete a group or an individual favourite. You can even add a new group by tapping

Add Group

.

Distributing Favourites between Different Users (only Palm OS)

After a HotSync between a PC and a Palm, the Palm transfers all the important files stored in the Palm, to a backup folder in the PC. This folder can normally be found in C:

\ <

program files

> \palmOne\ <

your palm name>

\backup.

Note that <

program files

> varies depending on your Windows language version and <

your palm name>

is the name of your Palm device.

In this case the name of the Palm is T3MW.

In this folder you can find all the favourites in the groups where they were saved. The group is saved as a

PDB

file. By double-clicking this

PDB

file, it will be

HotSynced

in to the Palm, the next time you run the HotSync function. See picture below.

This

PDB

file containing favourites can easily be shared between different users.

If you have more than one Palm account on your PC, then it is important to choose the

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Favourites

63

right Palm during a

HotSync

operation. And if you use a Palm with a PC which the Palm have not been in contact before, then it is important to do a

HotSync

and create an account.

3.6.2

Start here!

Start Here!

is a function that makes it possible to define a default starting point for the

QABrowser. Assume that you mostly use the QABrowser for measurement on radiography and that you use the real-time display to display all values.

Go to the screen where you want the QABrowser to start. Tap

Start Here!

to select this screen as starting point for the QABrowser. You can now quit the QABrowser. Restart and verify that it starts up with selected screen. Actually, Start Here! is a special case of the Favourites, as described above, and can thus be found there.

3.7

QABrowser Setup

The Piranha Setup is used to define different parameters that control the function of the QABrowser and Piranha. Open the QABrowser main menu and select

Setup

.

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QABrowser Setup

3.7.1

Regulations Setup

Regulations

is used to define the acceptance limits that are used in the built-in applications.

1. Tap the value you want to change. Write a new value on the graffiti area.

2. You can change parameter by tapping the parameter name at the top of the screen.

3.7.2

Units Setup

Units Setup is used to change the preferred unit of measure for dose and dose rate, as well as units for temperature and air pressure. These are then the default units for all new tests.

Tap the unit you want to change and tap the desired unit in the list that pops up.

When measuring in the RTD you can temporarily change a unit by tapping the unit text with the stylus.

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QABrowser Setup

65

3.7.3

Log Setup

The Log setup is used to define basic information about the measurement that is saved in the log file. You can also define:

To display the log file automatically when it is saved.

To always log data, as soon as a measurement is started.

Ask for a note every time a new log is started.

Additional data, such as detector setting are also logged.

For further details on this see topic Data Logging 57 .

3.7.4

Preferences Setup

Sleep time

defines how for how long time the handheld computer stays on when it is not used and charging is off.

Stay on in Cradle

defines that it should stay on as soon as it is connected to and powered from the Piranha.

Auto prompt

is for the built-in applications in multiparameter mode. It defines how long time the result from one exposure is shown before the cursor moves on to the next position.

Lock unit prefixes

means that the prefix of a unit is fixed and not auto-ranging.

Analyse waveform

means that the Piranha automatically analyses and determines the type of waveform.

Indicate trig

lets you select how a trig event will be presented to you. Can be all combinations of sound and graphics.

Active messages

lets you enable/disable the use of active messages (the QABrowser automatically changes range or filter when the signal or tube voltage is too low/high).

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QABrowser Setup

3.7.5

Detector Information

The detector information screen lists all detectors available for the system. For each module you can see the available detectors and probes.

3.7.6

System Info

System Info

is used to get information about the Piranha system.

Serial Number

The serial number for the system.

Firmware

Firmware version of the internal software that is used in the system.

Product v.

The product version is the hardware version. This is the version printed on the product serial label.

3.7.7

System Test

System Test

is used to test different functions in the

Piranha system.

Beep

generates a 2 second beep.

Play Melody

plays the famous Swedish hit song, "The

Final Countdown".

Filter Test

moves the filter in a special sequence and makes a double beep for each position. The sequence is

4-5-4-C-1-2-3-4-5-4-3-2-1-C.

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Battery & Power Status

67

3.8

Battery & Power Status

The battery status for the Piranha and handheld are displayed together on a informative display, as shown below. You access this screen on the menu (tap the icon) by selecting

Info - Power Status

.

Battery Level

For both the Piranha and the Palm you can monitor the charge level by the fill of the battery symbol.

See also Indicators and Connectors

10

.

If the Piranha is powered from batteries the following warnings are displayed when the batteries are low:

When the batteries are running low a warning message will be shown. You should now connect the power supply or USB cable as soon as possible.

When the batteries are too low to operate the

Piranha, an error message is shown. You should not continue to work without connecting the power supply or an USB cable.

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3. Description of the QABrowser

Indicators and Symbols

3.9

Indicators and Symbols

Different indicators (symbols) are used to indicate status and to guide you in different situations. You can tap same of the indicators to get more information:

This symbol may be preceding a text or a value. It indicates that if you tap it, a drop-down list with more choices will appear, allowing you to change the corresponding value/text/setting.

This symbol indicates that settings information is available. Tap this icon to open the additional information screen. Here are measurement information and settings for the Piranha and its detectors found. This menu is accessed when you need to override the default settings of the Piranha that are set by the QABrowser. See topic Settings 43 for more information.

This "play" symbol indicates that the system has been trigged, and the continuous readings (fluoro) are being updated. When the radiation stops this symbol will disappear and a green RTI logo will briefly be superimposed over the whole screen. If you get this symbol when there is no signal press reset. If it comes over and over you may need to increase the trig level, by raising the threshold, see topic Settings

43

.

This "pause" symbol indicates that hold has been activated during measurement on fluoroscopy.

This symbol indicates that there are more items not visible in a list. Tap the symbol or press the up/down buttons to view not visible items.

This symbol is similar to the previous. Tap to move the cursor bar up and down in the built-in applications (accuracy, linearity, reproducibility, and so on). Grey arrows indicates that the end has been reached. It may also be used to step between different "rows" in the Quickbar.

This symbol is also similar to the previous ones. It is used for the built-in applications (accuracy, linearity, reproducibility, and so on), when multiple parameters is measured, i.e. "All" etc. Tap left or right to move between the different reading screens. Grey arrows indicates that the end has been reached, as indicated by the text in between.

This is an animated symbol. Its "movement" indicates that the log is enabled and active. Tap it to toggle between pause and active.

This icon on the top left side of the Graffiti area takes you to the Favourites, see section Favourites 59 .

This icon on the bottom left side of the Graffiti area is the menu icon.

Tapping this symbol brings down the drop-down menu from the top of the screen.

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Indicators and Symbols

This icon on the bottom right side of the Graffiti area takes you to the settings screen, see section Measurement Settings

43

.

69

This icon is not used by the QABrowser.

Measurement symbols. These are shown in the upper rightmost corner of the real-time display (RTD) and application screens. These are either attention messages, settings affecting your measurement readings, or settings you have made. Especially when using favourites they will give you a quicker overview. A surrounding square indicates the relative position of the three first, as they may be shown simultaneously.

This symbol indicates that the function Beam Correction is active. The set beam correction factor can be changed under Settings

43

.

This symbol indicates that the function normalize to distance is active. The set distances can be changed under Settings

43

.

For mammography. This symbol indicates that a compression paddle is used in the beam. The doses measured by the Internal detector detector can then be compensated to simulate the scatter effect, that an ion chamber shows when a compression paddle is positioned directly above the detector.

The equivalent thickness and scatter factor can be changed under Settings

43 .

Waveform indication. This symbol indicates that the waveform was set or determined as DC/HF. Tube voltage readings are affected by this. The waveform functionality can be changed under Settings

43

.

Waveform indication. This symbol indicates that the waveform was set or determined as single phase. Tube voltage readings are affected by this. The waveform functionality can be changed under Settings

43

.

Waveform indication. This symbol indicates that the waveform was set or determined as 3-Phase 6-Pulse. Tube voltage readings are affected by this.

The waveform functionality can be changed under Settings

43

.

Waveform indication. This symbol indicates that the waveform was set or determined as 3-Phase 12-Pulse. Tube voltage readings are affected by this. The waveform functionality can be changed under Settings

43

.

Waveform indication. This symbol indicates that the waveform was set as

AMX-4, from General Electric. See Settings - Conditions

45

for more information. Tube voltage readings are affected by this. The set waveform can be changed under Settings

43

.

This symbol indicates that one or more measured value is not displayed with maximum accuracy. This indicator is for example shown when the

Piranha is unable to apply a correction/compensation to a measured value.

Tap the symbol to get a detailed description of the problem.

The indicators may appear in different situations and in different places in the

QABrowser but they always have the same meaning and functionality.

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Installation of Palm OS Handheld Computers

3.10

Installation of Palm OS Handheld Computers

Please note that if you purchased your Handheld Display (or Palm OS or Windows mobile handheld computer) either directly from RTI or a RTI dealer, the QABrowser is already installed and configured on the handheld. So if this is the case the only reason for you to install the software on your PC is if:

1. You need to update the QABrowser software on the handheld, using the QABrowser

Updater.

2. You have lost or uninstalled the QABrowser from the handheld.

If you have a Windows Mobile device, please see the

QABrowser for Windows Mobile

User's Manual

for instructions on how you install the QABrowser.

For the RTI Handheld Display or Palm OS handheld computer, see the HTML help file on your Product CD for details.

3.10.1

Updating QABrowser on the handheld

The QABrowser Updater helps you to install/update the QABrowser software on the handheld computer.

To update/install the QABrowser:

1. First install the QABrowser Setup as described in the previous chapter.

2. In the end of the installation process you will get the question if you want to run that updater immediately. If you have your handheld computer and the cradle available you can continue directly and step #4 below can be ignored. Perform step #6 and answer "Yes".

3. Attach the HotSync cable.

4. Go to

Start | RTI Electronics | QABrowser Updater | QAB Updater

to start the

QABrowser Updater.

5. The QABrowser Updater starts. If the PC is used with more than one handheld computer you are asked to select user.

6. Select the user name of the handheld computer and click the

OK

button.

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Installation of Palm OS Handheld Computers

71

7. The QABrowser Updater is now preparing the files that should be installed on the handheld computer. A message is shown when this is completed.

8. Now press the HotSync button on the cradle/ connector. A box appears on the screen indicating that the

HotSync process is active.

9. All the required files are now being installed onto your handheld computer. This process may take several minutes. When the

HotSync Progress

window disappears, all files have been transferred to the handheld computer. At the same time, a complete backup of your handheld has been done and saved on the PC.

10. You can now remove the handheld computer from the cradle. You may be asked to make a Reset of the handheld computer. Do that by tapping the

Reset

button.

The update/installation of the QABrowser is now completed.

Note that when you have updated you QABrowser, you may get an Attention message like one of these.

Then you must also update your Piranha firmware, see Updating the Firmware 32 for more information.

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Installation of Palm OS Handheld Computers

3.10.2

Uninstalling the QABrowser

There are two parts that you need to do to remove the QABrowser installation completely.

1. Remove the QABrowser on you handheld device.

2. Uninstall the QABrowser Updater on your PC.

Removing the QABrowser from your handheld

Simply remove by deleting the icon on the Palm. You find a

Delete...

menu in the

Application Launcher.

Removing the QABrowser Updater from your PC

This is accomplished by using the Windows Control Panel "Add and Remove Programs" or by choosing

Start | RTI Electronics | QABrowser Updater | Uninstall QAB

Updater

.

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Chapter 4

Measurement Principles &

Theory

74

4. Measurement Principles & Theory

4 Measurement Principles & Theory

The QABrowser has a number of measurement algorithms and applications built-in.

This section describes some about the principles, how some values are calculated, and the basic use of such measurements.

4.1

Overview of Capability for Measurement Modes

The following graph shows an overview of some common capabilities the different X-ray measurement types have in the QABrowser.

Modality

Radiography

Cine/Pulsed exposure

Fluoroscopy

Pulsed Fluoroscopy

Mammography

CT

Dental

Panoramic Dental (OPG)

HVL

Application

OK

OK

OK

OK

OK

OK

OK

Estimated TF Quick-HVL

OK

OK

OK

OK

OK

OK

OK

OK

OK

OK

OK

OK

OK

OK

OK

4.2

Measurement Type Settings

For both the QABrowser and Ocean a number of measuring settings and update modes can be selected, some of them also determines active sensitivity range (the selected integration time etc.) and also controls the way the displays and/or electrometers are reset. The table below shows the default settings used by the QABrowser.

Modality

Radiography

Cine/Pulsed exposure

Fluoroscopy

Pulsed Fluoroscopy

Mammography

CT

Dental

Panoramic Dental (OPG)

Light

AE

AE

C

C

AE

AE

AE

C

C

Update mode kV delay

(ms)

5

5

0

0

5

Post delay

(ms)

WF

(ms)

250 320

Auto reset

1000 320

250 320 Yes

1000

250

320

320

5 1500 640

200 250 640

Yes

200 250 640 Yes

– 250 640 Yes

Abbreviations:

AE

=After Exposure,

T

=Timed,

C

=Continuous,

FR

=Free run,

WF

=Waveform recording time

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4.3

Update Modes

4. Measurement Principles & Theory

Update Modes

75

As described under Measurement Type

Settings

74

and seen in the figure to the left, the following four update modes are available:

After exp.

, the QABrowser receives a new value when the exposure terminates. This means when the output goes under the trig level and stays there at least the time set by Post Delay under

Settings | Piranha

. Reset time is one second.

Continuous

, the Piranha is continuously sending data as long as radiation is detected. Displays in the QABrowser are updated about every four seconds.

Typically used for Fluoroscopy. Reset time is one second.

Timed

, the user sets a measurement time. The user then starts the measurement and the Piranha will measure all radiation received during the measurement time, without any trig levels or background compensation. When the time has passed, a reading will be presented. It has a long reset time for increased accuracy, which varies with the sensitivity, as seen in the table below.

Free run

, the Piranha will continuously measure the radiation without any trig levels or background compensations. No applications are available when using this mode. The mode has a feature called moving average which calculates the average of the measured values during a defined time, to increase accuracy by lowering the time resolution. This function gives a larger stability to the measurements. Free run also has a long reset time for increased accuracy, see the table below.

In Ocean the

Normal Mode

automatically handles

After exp.

and

Continuous

modes.

Default value is set according to selected type of measurement and this parameter normally never needs to be manually changed, unless really low-level measurements are to be accomplished.

However, to measure on real low-level signals the

Timed

or

Free run

update mode may be used

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4. Measurement Principles & Theory

Update Modes

Update mode

After Exposure

Timed (Low/High sens.)

Timed (Very High sens.)

Continuous

Free run (Low/High sens.)

Free run (Very High sens.)

Auto reset

Yes

Reset time

(s)

1

4

Sample time

(ms)

Min. WF rec. time

(s)

Max. WF rec. time

(s)

0.5-64 0.32

0.5-64 0.32

40

40

30 20-2560

1 0.5-64

13

0.32

4 0.5-64 0.32

30 20-2560 13

2000

40

40

2000

Note

: The

Sample time

is the "resolution" of the waveform, i.e. time between two samples.

Auto reset

means that a reset is performed after each trig off.

Reset time

is the time it takes to perform a reset each time you hit

Reset

.

Sample time

is the time between individual data point of the waveform.

Waveform recording time

is the range of user selectable recording times the Piranha allows.

Note that in

Timed

and

Free run

you may get negative readings, for instance if you press reset when a signal is present on the detector.

4.3.1

Using Timed Update Mode

Change mode by going into settings using the symbol or the graffiti icon. Then select the Piranha section as shown to the right, and input the desired measuring time.

Tap

Back

to exit settings.

The measurement is started by tapping the

Start

button.

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Update Modes

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During the measurement the time left will count down and it can be stopped by tapping the

Cancel

button.

The measured time will sometimes not be exactly what was set under settings, but the measured value is the one used for all calculations. The dose rate shown for Timed mode will always be mean dose rate during the measurement cycle, i.e. the measured dose divided by the measured time.

The Timed mode can be very useful both for very low dose rate measurements as well as for long duration measurements.

For extreme low-level dose measurements you can improve your reading by subtracting the background level. First do a Timed measurement without exposing the detector to radiation and then do the same with radiation. The timed mode will use the same measuring time and the first reading can be subtracted from the first.

Just make sure not to do a

Reset

between these measurements, as the

Reset

will also make an offset adjustment. Note also that low-level readings may give inaccurate kV readings.

For long duration measurements, cases with slowly rising and falling output, or cases with very low pulse rate, timed mode may also be useful. For instance on CT machines where the rotation cannot be stopped.

4.3.2

Using Free Run Update Mode

Free run update mode works almost exactly as the ordinary

Continuous

update mode.

There are however two differences:

1. Since there is no trig level, you will be able to measure lower, but there will be no time reading unless the signal goes over the trig level.

2. You can select a moving average function. This lets you set a time for moving average, this time acts as a averaging window, moving through time.

Moving average

This function is intended for low level dose rate measurements where increased sensitivity and stability is needed. The function uses a moving average algorithm where the number of seconds is selected by the user.

During the reset process the user must make sure that the detector is not exposed to

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Update Modes

radiation. After the reset procedure the Piranha will start to show a value calculated as the sum of the last X values divided by X (X is the number of seconds chosen by the user). For each new second that passes the last value in the stack will be discarded and a new value added. This means of course that it will take X seconds before the Piranha starts to show a valid value when the detector attached is exposed to a steady radiation level. In the same way it will take X seconds for the Piranha to show a zero value after the radiation has ended. Great care must be taken into choosing a time constant fitted to the nature of the signal.

Example

If you set the time to 8 seconds, each reading, will be the mean of the reading of the last

8 seconds. This means that it will take 8 seconds until the reading reaches a started set radiation level.

4.4

Display Messages and Active Messages

Even though the range of the Piranha measurement system is quite wide, sometimes the signal may get too low or too high. To inform you of this, there are display messages. These are mainly of two types, Active or Passive. Active messages are shown when the hardware settings can be adjusted to adapt the measurement ranges.

The active message will just inform you that it is making an automatic adjustment and you can simply do another exposure/measurement. The active messages can be disabled, see the following section.

The passive display messages indicate what the problem is and possible remedies for them. These will show if there are no active messages, the active messages are disabled, or when no more automatic adjustment can be done.

4.4.1

Active Messages

In some rare occasions it might be helpful to disable the active messages, for instance if the detector signal is very noisy or there are pre-pulses that makes the system autoadjust erroneously.

Turning the

Active messages

to "

Off

" in

Setup | Preferences

does this.

Below the various active messages are shown. Make sure to follow the text shown, since reset may be performed automatically. Otherwise do a

Reset

again.

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Display Messages and Active Messages

High signal

One or several detectors have too high signal.

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Low signal

The Piranha detects a signal but it is too low to present a reliable result.

High kVp

Measured tube voltage is higher than that of the selected kV-range.

Low kVp

Measured tube voltage is lower than that of the selected kV-range.

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4.4.2

4. Measurement Principles & Theory

Display Messages and Active Messages

Display Messages

High signal

One or several detectors have too high signal.

Lower the set sensitivity under settings.

Reduce the mA and/or increase the distance from tube to detector.

Exp. < Delay

The exposure time is too short compared to the delay time.

Increase the exposure time and/or reduce the values of delay and/or window time.

Keep in mind that the type of measurement sets the delay time value. The standard value for radiography use is 5 ms, but for dental it is 200 ms. See Measurement Type Settings

74

.

High kVp

Measured tube voltage is higher than that of the selected kV-range.

Change to a higher kV-range.

Low kVp

Measured tube voltage is lower than that of the selected kVrange.

Change to a lower kV-range.

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Low Signal

The Piranha detects a signal but it is too low to present a reliable result.

Increase the mA and/or decrease the distance from X-ray tube to detector or change the sensitivity for the dose parameter to

High sensitivity

or even

Very High sensitivity

. Also the

kV sensitivity

can be changed. You find these settings if you tap the symbol.

Reposition Detector

The radiation signal on D2 and D1 is not within 5 % (quota not between 0.95 to 1.05). The most common reason for this is that the detector area is only partially irradiated, the detector is tilted, or the filtration differs between D2 and D1

(e.g. heel effect).

Change the field size or move the detector into the central beam.

Negative Signal

The electrometer module detects a negative signal.

Most common is that the mAs-probe have been connected in the opposite direction on the HV cable.

Change the polarity of the current probe.

Also small negative drift created from the detector source, typically initially after reset can give this message.

Do a

Reset

to clear the message.

This message does not appear in the

Timed

and

Free run

update modes.

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Waveforms and Triggers

4.5

Waveforms and Triggers

To get an understanding of how triggers, delays, and windows work, take a look at the waveform below. This is what happens during a standard exposure:

1. The radiation starts, i.e. it goes over the detector's lowest trig level.

2. The signal reaches 50 % of its maximum. This is the starting point for the irradiation time calculation. (The level is user adjustable.)

3. The signal reaches its maximum.

4. The

Delay

time is reached. (User adjustable.) kV integration window starts.

5. The

Delay

+

Window

time is reached. (User adjustable.) kV integration window stops.

6. The signal goes below 50 % of its maximum. This is the end point for the Irradiation time calculation. (The level is user adjustable.)

7. The radiation ends, i.e. it goes under the detector's lowest trig level.

8. If the signal has been below the trig level during all of

Post delay

, the exposure is considered finished. All exposure readings are calculated.

Integrated signal (dose, mAs, etc.)

Is the integration of all signal which means the area below the curve above from point 1 to 7. During the measurement (exposure) the accumulated signal (dose, etc) is displayed where applicable.

Signal rate (dose rate, tube current, etc.)

During the measurement the mean signal for the last second is displayed. When the measurement (exposure) is over, point 8 above, the mean signal for the whole measurement is displayed. This signal rate is calculated as all integrated signal (as described above) divided by the irradiation time. If no irradiation time is possible to calculate, the radiation time is used instead.

This means that for long measurements you may see a change in the rate value (dose rate, etc) when the measurement is finished, if the signal level was changed during the measurement.

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Measurement Principle for the Piranha

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4.6

Measurement Principle for the Piranha

The following are the key features of the Piranha design:

Small size

Optimized filter packages for five different kV ranges

Very sensitive and wide dynamic range

Check filter for measurement geometry verification

Single exposure estimation of total filtration and Quick-HVL

Single exposure estimation of generator waveform type

The design of the detector package is very important to be able to measure kV and dose correctly in the whole range of 20 to 155 kV.

The Piranha design makes it possible to measure small field sizes, less than 3 mm width, and low output levels down to approximately 1 µGy/s. Basically the detector packages consist of four separate electrometer channels connected to detectors D1,

D2, D3, and D4 and a moveable filter package that can change to one of six positions, each a combination of different filters for the detectors. One of these positions is used as a "check-filter". It has the same filter thicknesses for both D1 and D2. When the detector is perfectly positioned and both detectors have the same radiation the ratio between the two signals should thus be exactly "1.000". This is very useful information, and testing this makes sure that your measurement geometry is fine, giving reproducible readings. The other 5 filter pairs have different thicknesses all optimized for different ranges of the tube voltage; two (1 and 2) are used for the low mammography energy range 20 to 45 kV, and three filters (3 - 5) are used for the radiography range 35 to

155 kV (35 - 75, 55 - 105, and 80 - 155 kV).

Using these four signals S1-S4 (from detectors D1 to D4) the Piranha can accurately calculate the corresponding tube voltage. The signal S3 is not affected by the moveable filters and is designed to measure the dose. This detector is marked by a square inside the rectangular detector area on the top panel. The reference depth for the sensitive area of the dose detector is 10 mm under the Piranha top panel surface.

The detector D4 is placed directly under D3 with additional filter in between. The ratio between S3 and S4 is used to estimate the total filtration for the radiography range.

Using these signals together more accurate dose and tube voltage readings can be obtained.

Since all signals is measured simultaneously and with a relative high speed, the Piranha can thus automatically compensate the kV and dose for the dependence of the waveform and inherent/added tube filtration.

4.7

HVL & Total Filtration

HVL is a method of specifying the radiation quality. The half-value layer is defined as the thickness of a specified material that attenuates the X-ray beam to one-half of its value in absence of that material, usually aluminium. See also Application Note 03-

009/01 that can be downloaded from RTI Electronics web page at http://www.rti.se

.

From the HVL-value the total filtration value can be estimated. See Application Note 1-

AN-52020-11 from RTI Electronics AB.

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HVL & Total Filtration

To measure the HVL:

1. Use the Piranha HVL stand on the table-top.

2. Set the generator to 80 kV/25 mAs.

3. If the display is unstable; press the Reset button.

4. Use some form to record your measurements.

5. Begin with 3 exposures without any added aluminum filter to get the zero-point and to check the consistency of the generator.

6. Add the aluminum filters, 1, 2, 3, and 4 mm, and record the readings. Make a measurement for each thickness and use the mean value.

7. Plot the results in a semi-logarithmic graph, set the value for 0 mm of added aluminium to 1.0.

8. Join the measured points with a curve and find the value of added filtration required to reduce the exposure to 0.5.

9. We find from the semi-logarithmic plot that the measured half-value layer is 3.3 mm

Al.

To measure Total Filtration:

In order to measure total filtration with one exposure optimally, there are some settings to be aware of. Since the highest accuracy is obtained between 60 and 120 kV, we recommend to do the measurement of the total filtration in between, at 80 kV. The

Piranha is also calibrated for the total filtration at this kV. Use a high signal level, i.e.

200 mA during 200 ms to get a stable result. It does not matter if you intend to do measurements at a higher or lower kV than this, this measurement aim to get a correct value of the total filtration.

See the graph below for optimum choice of method.

Hence, choose 80 kV, 200 mA and 200 ms and make an exposure. The total filtration will be displayed in a pop-up screen. Tap

Keep

and the value is stored and will be used on all further measurements. The pop-up screen will be displayed whenever the value of the total filtration is changed.

Manually you can do this by entering the settings screen by tapping the icon, as shown below. As default value the total filtration is set to

Estimate

. Measure the total filtration and then enter the settings window again. Now choose

Set

and enter the measured value.

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4.8

Linearity

The output in mGy/mAs for different mAs stations should remain constant if the kVp and distance are maintained constant. This can be checked by measuring the coefficient of linearity. The coefficient of linearity is defined as:

L

1 2

X

1

X

1

X

2

X

2 where:

X = Dose/mAs

, and

X

1

and

X

2

(

X

1

and

X

2

) are measured at adjacent mAs settings

To check the mAs linearity:

1. Place the detector on the table-top. If patient-equivalent phantom should be used it is recommend to use the Piranha HVL stand to simplify the set up. Use 2 pieces of

10 mm Al filter as "patient -equivalent" filter in the beam.

2. Set the X-ray generator to technique factors commonly used clinically.

3. If the display is unstable; press the Reset button.

4. Use some form to record your measurements.

5. Make exposures at different mAs settings and both for small and large focuses.

6. Calculate the coefficient of linearity for adjacent measurements.

An acceptable value for the coefficient of linearity is less than 0.10.

A short example: measurement 1 : X

1

= 13 µGy/mAs measurement 2 : X

2

= 14.6 µGy/mAs measurement 3 : X

3

= 12.8 µGy/mAs

Then:

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2

L

1 -

4. Measurement Principles & Theory

Linearity

13.0

13.0

14.6

14.6

1.6/27.6

0.05797

and:

3

L

2 -

14.6

12.8

14.6

12.8

1.8/27.4

0.06569

Of which both is below the 0.10 limit.

4.9

Reproducibility

Reproducibility is checked to find out how constant the output is when an X-ray exposure is repeated many times. One method is to check the coefficient of variation.

The coefficient of variation is defined as:

s n x i i

1

n x

1

x

2 where

x n i

= Individual exposure readings

= Number of readings

= Mean value of readings

To check the output reproducibility:

1. Place the dose detector on the table-top (the patient-equivalent phantom is not necessary since this measurement can be made as a relative measurement).

2. Set the X-ray generator to technique factors commonly used clinically.

3. If the display is unstable, press the Reset button.

4. Use some form to record your measurements.

5. Make 5 to 10 exposures and record the reading for each exposure.

6. Calculate the mean value, difference from mean value and square of differences.

7. Add all squared values and divide by (n-1) to get the variance. In this case n=10.

8. Calculate the square of the variance, i.e. the standard deviation, and divide it by the mean value of the n measurements

An acceptable value for the coefficient of variation is less than 0.05.

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Measurements with the

Piranha System

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5. Measurements with the Piranha System

Introduction

5 Measurements with the Piranha System

5.1

Introduction

The Piranha system can, depending on model, measure up to eight parameters simultaneously plus three waveforms from a single exposure: kVp

Dose and dose rate

Exposure time

HVL

Estimated total filtration and determined waveform type mAs and mA pulses kV waveform

Dose rate waveform mA waveform various pulsed fluoroscopy parameters

Using the Piranha alone, 6 parameters and two waveforms can be measured simultaneously.

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Radiography

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5.2

Radiography

This topic will describe how to measure kVp, dose, and exposure time on a radiographic unit using the Piranha.

Set up the Piranha and the handheld computer according to the description in Setting Up the Piranha

12

.

Measuring the kVp on a radiographic units is straightforward since the Piranha can automatically detect and compensate for variation in the radiation quality. It is also easy to check that the detector area is fully and uniformly irradiated. Practically this means that the kVp value can be measured in the range 1.0 to 50 mm of total filtration.

Therefore the Piranha can be placed in the beam wherever you want, as long as it passes the

Position

Check

. It also has a very wide dynamic range so it very rarely happens that the signal level is not enough to get a correct kVp value. The radiography kV range is 35 to 155 kV.

You can either select the tube voltage as single parameter or together with dose, dose rate, and exposure time. As complementary information estimations of the total filtration and type of waveform are made. This feature uses the kV filter R1[4] (55 - 105 kV). This is the default kV range for radiography when the Piranha is turned on.

The displayed dose value has no energy dependence since it is automatically compensated for each exposure since both the kV, estimated filtration, and the waveform are measured. Even without compensating the dose value, the energy dependence is small in the radiography range. This is also true for the kVp value. A

10 mm Al change of the beam filtration at 70 kV increases the kV only about 3.5 kV without automatic compensation. With compensation the change in kVp is less than

0.3 kV.

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Radiography

If any of the displayed values are not possible to compensate or cannot be measured with full accuracy the symbol is displayed at the top of screen.

When the symbol is shown you can tap it, to get more information.

Tapping menu

Main

|

Help

brings down the built-in help system text including images describing the most important aspects of the program and a few hints of how to set-up the measurement.

Please note that you can measure the exposure time both in time ("ms", "s") as well as pulses. You can also change the dose and dose rate units. Tap the dark part of the display where the unit and its prefix are displayed to get the list of units, or for the supplementary data at the bottom, you tap the unit.

The value for the new unit is automatically calculated and displayed.

A delay of 5 ms is standard but can be changed when necessary. It is important to select an exposure time longer than the delay time to obtain a accurate reading. The settings of the sensitivity both for dose and kV are preset depending of type of measurement selected. You may get a "Lo. Signal" message if you try to measure in fluoro mode when the selected type of measure is radiography. You can then change the sensitivity by tapping the symbol and select

Internal detector

from the

Conditions

menu.

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However, if you really want to measure in fluoroscopy mode it is better to select

Fluoroscopy

as type of measurement. The sensitivity is then automatically set to

"

High

".

To measure kVp only, select

Tube voltage

instead of

All

as parameter for type of measure.

To be able to trust the reading it is always a good practice to first do a check measurement, to verify that the whole detector area is uniformly irradiated. This is done with the

Position check

that can verify the uniformity of the beam. The kV and radiation waveform is always acquired together with the real-time display values and can be displayed by tapping

Wave

. Applications and logging of the real-time values are described earlier.

5.2.1

kVp, Time, Dose, and Dose Rate

To measure on radiographic units:

1. Set up the Piranha and the handheld computer according to the description in Setting

Up the Piranha 12 .

2. Place the detector on the table at the distance that is clinically relevant.

Place the Piranha in the direction indicated in the figure below

Adjust the collimator so the radiation clearly covers the detector rectangle marked on the Piranha top panel, but try to keep the field size inside the top panel size to minimize scatter. Recommended field size is 20×40 mm. Furthermore the Piranhasurface should optimally be placed perpendicular to the focal spot, see also Angular Sensitivity, Piranha

24

.

3. Selecting only one parameter enables you to see the measured values from a distance of several meters.

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Radiography

5. It is recommended to make a check measurement at 70 kV to confirm that the detector area is uniformly radiated.

The Piranha automatically changes back to the previous selected kV range. As default this is radiography range R2 indicated by a [4] on the QABrowser screen.

6. Set kVp and mAs (or mA/time) to the desired values.

7. Make an exposure. The RTI logo flashes to indicate that the Piranha has detected the exposure.

The Piranha now first analyses the beam and displays the type of waveform. This is done once for every test.

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Then the estimated total filtration is displayed (estimated in the range of 50 - 150 kV).

Depending of the selection of display parameter different display screens may be presented.

8. Tap

Wave

to study the waveforms.

9. You can use the pen to move the cursor.

10. Tap

Back

to return to the real-time display.

11. Repeat the measurement for other generator settings or select an Application (tap

Appl

) to measure further.

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5.2.2

5. Measurements with the Piranha System

Radiography

Dose Measurements with Piranha Dose Probe

1. Place the Piranha Dose Probe in the field and connect the cable to the Piranha input.

2. Set up the Piranha and the handheld computer according to the description in Setting Up the Piranha

12

.

3. Follow the same steps as for the measurement with

Piranha, but select

Dose

as parameter and then

External.

3. Set kVp and mAs (or mA/time) to the desired values.

4. Make an exposure. The RTI logo flashes to indicate that the Piranha has detected the exposure.

5. Read the values. As complementary information the dose rate and exposure time is also displayed below. Tap

Wave

to view the corresponding dose rate waveform.

6. Repeat the measurement for other generator settings or select an application to measure further.

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5.2.3

5. Measurements with the Piranha System

Radiography

HVL Application

HVL is calculated in the standard way using an

HVL stand and a set of aluminum filters.

The general HVL method that can be used when measuring with an external detector connected to the electrometer module is described in section

HVL & Total Filtration

83

.

Using the Piranha and the built-in HVL application correct HVL value and total filtration value can be measured and calculated.

95

Set up the system the same way as described earlier to measure dose in radiography beams and select the

Piranha. The only difference is that you select the built-in HVL application for the dose measurement. The HVL application can be found in the Dose test (under

Appl

on the Quickbar).

Follow the instructions in that application to change the filter in the beam according to the set values.

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Radiography

When the dose value has been reduced to less than half the HVL and total filtration value are calculated.

Tap

Graph

to view a graphical presentation of the result.

It is recommended to use the built-in HVL application (or Ocean) to evaluate HVL.

5.2.3.1

Introduction 2

The Piranha system can, depending on model, measure up to eight parameters simultaneously plus three waveforms from a single exposure: kVp

Dose and dose rate

Exposure time mAs and mA

Estimated total filtration and determined waveform type kV waveform

Dose rate waveform mA waveform

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Using the Piranha alone, 6 parameters and two waveforms can be measured simultaneously.

5.2.3.2

kVp, Time, Dose, and Dose Rate 2

To measure on radiographic units:

1. Set up the Piranha and the handheld computer according to the description in Setting

Up the Piranha

12

.

2. Place the detector on the table at the distance that is clinically relevant.

Place the Piranha in the direction indicated in the figure below

Adjust the collimator so the radiation clearly covers the detector rectangle marked on the Piranha top panel, but try to keep the field size inside the top panel size to minimize scatter. Recommended field size is 20×40 mm. Furthermore the Piranhasurface should optimally be placed perpendicular to the focal spot, see also Angular Sensitivity, Piranha

24

.

3. Selecting only one parameter enables you to see the measured values from a distance of several meters.

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Radiography

5. It is recommended to make a check measurement at 70 kV to confirm that the detector area is uniformly radiated.

The Piranha automatically changes back to the previous selected kV range. As default this is radiography range R2 indicated by a [4] on the QABrowser screen.

6. Set kVp and mAs (or mA/time) to the desired values.

7. Make an exposure. The RTI logo flashes to indicate that the Piranha has detected the exposure.

The Piranha now first analyses the beam and displays the type of waveform. This is done once for every test.

Then the estimated total filtration is displayed (estimated in the range of 50 - 150 kV).

Depending of the selection of display parameter different display screens may be presented.

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Radiography

8. Tap

Wave

to study the waveforms.

99

9. You can use the pen to move the cursor.

10. Tap

Back

to return to the real-time display.

11. Repeat the measurement for other generator settings or select an Application (tap

Appl

) to measure further.

5.2.4

Quick-HVL and Total Filtration

Total filtration

A quicker way to get an estimated value with acceptable accuracy is to use the "oneshot" method that is a standard complementary information feature for the Piranha kVp determination (described earlier in this manual). The total inaccuracy is about ±0.3 mm in the range of 2 to 10 mm and ±10 % in the range 10 to 25 mm, see Specifications,

Piranha

14

. The purpose of this value is to always be able to calculate correct kVp and dose value independent of beam-filtration. But it can also be used as a quick way to estimate the filtration and alert you if the filtration has changed since last measurement of the HVL value.

The following examples very clearly shows the excellent independence of the beam filtration for kV and dose readings.

Three exposures were made with 3 mm Al, 6 mm Al, and 12 mm Al. The Piranha was used to measure kVp, exposure time, dose, and dose rate. The pictures are stored when the QABrowser shows estimated total filtration. The kVp value is also visible.

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Radiography

As seen, the measured kVp value is within 0.4 kV for the different total filtration values.

Quick-HVL

If the parameter "

All w. TF+HVL

" is chosen, the QABrowser will display both estimated total filtration and quick-HVL values for every measurement. Below a sequence of measurements is shown displaying how the total filtration and HVL can be determined at three different kV settings with only three exposures:

With the initial exposure the total filtration is displayed (6.8 mm Al) before the kVp is displayed. Then the measured kVp is shown (117.0 kV) and the estimated total filtration and HVL are shown as supplementary information. The HVL is calculated to be

6.42 mm Al. The set kV was changed and the Piranha measured 102.6 kV. The HVL is calculated at 5.70 mm for this kV. The set kV is changed again and a third exposure is made. The kV is measured to be 83.53 kV and the HVL is calculated to be 4.69 mm Al.

Notice that all three measurements of total filtration were 6.8 mm Al.

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5.3

5. Measurements with the Piranha System

Cine/Pulsed Radiography

101

Cine/Pulsed Radiography

The cine/pulsed exposures application is aimed to check Cat-Lab and cine X-ray units that are able to deliver high output short duration X-ray pulses (in the millisecond region) and acquire each individual

"pulse" as an X-ray image. The images are used to study dynamic structures in the patient body, often in combination with the injection of a contrast medium during the investigation. The same type of X-ray system also can be used for pulsed fluoroscopy where the X-ray output is much lower. Therefore, depending on type of acquisition mode, it may be better to select the "pulsed fluoroscopy" measurement type for the Piranha. Please consult the next section of the manual if this is the case.

For under-table cine measurement turn the Piranha upside-down. An optional detector rod is available that can be used to put the detector in position on the image intensifier without risk for hazardous X-ray exposure when monitoring.

The

Position Check

should be used to confirm the position. To be able to protect the image intensifier from the relative high output cine pulses a lead apron can be placed over the image intensifier input screen. The Piranha automatically measures the number of pulses based on information from the radiation waveform. It uses a 50 % trig level based on the maximum signal level.

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5.3.1

kVp, Time, Dose, and Dose Rate

Use the same procedure as for the normal radiography measurement but select the

All...

parameter.

If only

Tube voltage

is selected:

5.3.2

Pulse Measurements with Piranha Dose Probe

Use the same procedure as for the normal radiography measurement. Note that if it is difficult to get a good pulse rate reading, you may use a manual pulse rate setting, as described under Settings

43

to get a dose per pulse reading.

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5.3.3

HVL, Quick-HVL, and Total Filtration

Use the same procedure as for the normal radiography measurement.

Note that if it is difficult to get a good pulse rate reading, you may use a manual pulse rate setting, as described under Settings

43

to get a dose per pulse reading.

5.4

Fluoroscopy and Pulsed Fluoroscopy

For under-table fluoro measurement turn the Piranha upside-down. Use the optional detector rod to be able to put the detector in the cassette holder or on the image intensifier without risk of hazardous X-ray.

The

Position Check

should be used to confirm the position of the Piranha. When you select fluoroscopy or pulsed fluoroscopy (as type of measurement) the Piranha system automatically changes to continuously updating the display and using the highest possible sensitivity.

When parameter

All...

is selected, kVp, exposure time, and dose rate are measured and the display is updated approximately every four seconds.

If dose rate or image intensifier dose rate is selected the Piranha or external Dose

Probe can be used.

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Normally the external Dose Probe is used to be able to measure the lowest possible dose rate levels down to 0.1 µGy/s. Another reason to use the external Dose Probe is that the detector is much smaller than the Piranha making it easier to position in front of the image intensifier without affecting the measuring field for the mA feedback loop.

If the image intensifier manually can control the mA and kV, then you can use the

Piranha for measurements down to about 0.7 µGy/s. For pulsed fluoroscopy even lower levels can be measured.

As a secondary parameter the total dose is accumulated. After you have turned off the fluoroscopy unit, this value is used to calculate the average dose rate as total dose divided by the exposure time.

Note that for very low dose rate values the exposure time cannot be measured accurately and the last dose rate value cannot be stored automatically in the display.

Then tap

Hold

to "freeze" the current value in the display. The waveform is also acquired when you tap

Hold

. Waveform is also automatically acquired when the selected delay time expires.

Select "I.I. input dose rate" as measuring parameter to be able to measure lowest possible dose rate and tap

Hold

to "freeze" current value in the display. The total accumulated dose is shoved after you have switched off the fluoroscopy unit.

5.4.1

Image Intensifier Input Dose Rate

Use patient equivalent phantom to measure the image intensifier input dose rate according to manufacturer's specification:

1. Connect the Piranha Dose Probe to the Piranha.

2. Set up the Piranha and the handheld computer according to the description in Setting

Up the Piranha

12

.

3. Select type of measurement.

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4. Select

I.I. input dose rate

from the menu.

5. The Select Detector screen is now displayed. Select External.

6. Tap

Select

.

7. Place the Piranha Dose Probe in front of the image intensifier but outside the measuring field for the mA feedback loop. You may use the optional detector rod that can be attached to Piranha Dose Probe to position the detector without risk for hazardous X-ray exposure. Observe the image on the monitor.

8. The real-time display is now displayed. Set the generator. Tap

Reset

.

Since the external dose probe (Piranha Dose Probe) is not sensitive to back scatter, a lower value compared to a transmission ion chamber is typically detected (typically in the range of 5 - 20 %).

You may use the

beam correction factor

to make automatic corrections. The

beam correction factor

may also be stored permanently in a

Favourite

for easy access.

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9. Start the fluoroscopy. A little triangle is displayed, indicating that the Piranha has detected the radiation.

10. The figure to the left shows the real-time display during fluoroscopy. The image intensifier input dose rate is measured and the display is updated approximately every four seconds. Tap

Hold

to "freeze" the currently shown value in the display. The waveform is also acquired when Hold is activated.

11. Release hold by tapping

Hold

again.

12. Stop the fluoroscopy.

13. Read the values.

5.4.2

kVp and Dose Rate

Use the same procedure as for the image intensifier input dose rate measurement but select

All...

parameters instead.

1. The first screen shows how the continuous updated display looks like. The little black arrow indicates that the radiation is detected and the display is updating every four seconds.

2. The second screen shows that the Piranha has detected that the fluoroscopy have stopped by flashing the logo and then freeze the values. Note that the last registered kV value may be lower than the one measured during the exposure. The last display update may occur when the exposure is switched off and the kVp is captured on the

"falling edge". The dose rate shown after the logo flashes is the average dose rate of the entire exposure.

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3. Tap

Hold

to acquire waveforms. The third screen displays the waveform for the earlier screen.

4. Tap

Hold

again to "release" the display.

5. The last screen above shows actually the same measurement with added 10 mm filter to reduce the dose rate even further. Note that the kV value is the same since the Piranha, even on this extremely low level, still makes corrections for the beam filtration.

The Piranha can measure both kV and dose rate at very low levels for instance on Mini

C-arm systems. Piranha can (as an example) successfully measure the tube voltage as low as 43 kV with a 25 µA tube current.

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5.4.3

HVL, Total Filtration, and Quick-HVL

HVL can be measured in a similar way as described for the radiography measurements but the dose rate value is used instead.

1. Select

Dose rate

.

2. Tap

Appl

and select

HVL

.

3. Use the

Hold

button to store a reading and move to next line when the displayed value is stable.

Total Filtration and Quick-HVL

The total filtration is measured continuously when the Piranha is used under fluoroscopy. The following pictures illustrates this excellent feature for the Piranha and the Internal detector (shown for Barracuda MPD):

The fluoro is started and the total filtration is estimated and automatically displayed during two seconds.

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The displays with measured values are continuously updated every four seconds.

Add 10 mm of aluminum. The Piranha will "notice" that the filtration is changed and shows a new total filtration value.

The dose rate is now much lower. The added filtration does not affect measured kVp at all.

Note how the Piranha directly responds to a sudden change of the filtration. The display is continuously updated with the kV, time and dose-rate. The dose rate value decreases when the extra 10 mm Al is put in the beam but the continuously updated kV value is practically are the same.

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Furthermore, if the parameter "All w. TF+HVL" is chosen, the QABrowser will display both estimated total filtration and quick-HVL values for every measurement shown above.

Conclusion:

For the first time, trustable kV and filtration measurements can be made on an X-ray unit. This is of special interest where the filtration not easily can be measured with a conventional HVL method or the filtrations actually is changed during the fluoro exposure or actually even not are known before.

Most other invasive kVp meters have a correction for the kVp of around 5 to 10 kV for a change of the beam filtration of 10 mm Al. The correction graphs given, does not help if the actual beam filtration are not known. The Piranha system detects and compensates automatically for a change of beam filtration. See Specifications, Piranha

14

, for details of the range of beam filtration.

5.4.4

Pulsed Fluoroscopy

Select type of measurement in similar way as for normal continuously fluoroscopy to setup the system.

Piranha is set-up for this application to calculate the number of pulses per second (Hz or pps), the dose/pulse, and pulse dose rate. The picture below explain the difference between the pulse dose rate and the traditional dose rate.

(Note that for DC waveform, pulse dose rate and dose rate gives the same value.)

When measuring tube voltage on pulsed fluoroscopy there is an additional waveform type available. This waveform type is called

pulsed

and is recommended for pulsed fluoroscopy measurements, especially if the pulses are not square wave shaped, since this can result in low tube voltage readings.

Example of measurement on pulsed fluoroscopy

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The following pictures illustrates how the Piranha system is used this type of measurement.

111

These pictures describes the check of the output levels in pulse fluoroscopy mode (showing Barracuda MPD).

This example shows measurements of dose/pulse, dose rate, and pulse rate on an ordinary C-arm system.

Example of more measurement done using this application:

The first slides are the measuring results of measuring on a 5 Hz fluoroscopy system

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using the Piranha Dose Probe.

-

Hints:

Pulsed fluoro screen is very handy to use for several applications and is not restricted to only measure pulsed fluoro.

It has application when measuring in Cine mode with heavy filtered beam that make the signal too low to use the Cine mode or when the dose rate is extremely low. Then the noise level is too high to detect the pulses in the signal. The pulsed fluoro mode works also well on X-ray generators that only have a continuous fluoro output.

The Dose/pulse screen has been configured to always display the

Dose rate

and

Pulse dose rate

continuously during the measurement period, even when pulse information is lacking. Be aware of that during the fluoro the continuous dose rate value is displayed but the dose rate value that is stored in the display after the measurement is based on the total dose divided by the measured exposure time.

1. X-ray on, momentary reading 2. X-ray on, momentary reading 3. X-ray off, mean value displayed

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5.5

Mammography

This topic will describe how to measure kVp, dose, HVL, AGD (MGD), and time on a mammography unit using the Piranha.

5.5.1

General

To measure kVp on a mammography unit is straightforward. This is true since the

Piranha automatically can detect whether the detector area is not fully uniformly irradiated, by means of the

Position Check

. The mammography kV calibrations available for the Piranha is ranging from 18 to 49 kV. To confirm which range is used the digit 1 or

2 is displayed in square brackets on the bottom left corner of the QABrowser screen, as shown below.

RQ (Radiation

Quality) Code

Range

Tube Voltage Range for this RQ

Radiation Quality

Selector

For new calibrations, only range 2 is being used. See the specifications section

Specifications, Piranha

14

, for details about the different calibrations.

Please note that:

Mo/2 mm Al (M2)

Rh/1 mm Al (M5) supports only kVp measurement, no dose measurement with Piranha is possible.

Mo/2 mm Al is not used that often but the GE DMR unit use Mo/1 mm Al so simply add one extra 1 mm Al in the beam when measuring kVp. This since the kV of the generator is the same regardless of the filtration.

You can either select the

Tube Voltage

as single parameter mode or

All

and get kVp together with dose, dose rate, and time.

The displayed dose value has very little energy dependence because the dose value is automatically compensated, using the tube voltage, which is measured simultaneously for each exposure.

If any of the displayed values cannot be compensated or cannot be measured with full accuracy, the symbol is displayed at the top of the screen. If the symbol is displayed you can tap it to get more information.

You can also change the dose and dose rate units. Tap the dark part of the display where the unit and its prefix are displayed to get the list of units. The value for the new unit is automatically calculated and updated.

A delay of 5 ms is standard but can be changed. If you get a

High kVp

message you

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have probably selected a set kV value higher than the actual measuring range. Another reason may be that you have selected wrong radiation quality compared to what the generator is set to.

To be able to trust the kVp reading it is always very important to make the

Position Check

to verify that the whole detector area is uniformly irradiated.

The

Position Check

is normally started automatically every time you change R

adiation Quality

, but please make sure to do a

Position Check

every time the Piranha is repositioned.

The kV and radiation waveform is always stored together with the RTD values and can be displayed by tapping the

Wave

button. The kVp calibration for Piranha is made without the compression paddle in place.

The purpose of dose measurement is often to determine the ESAK,

Entrance Surface

Air Kerma

(or ESE,

Entrance Skin Exposure

).

It is recommended to perform dose measurements according to a mammography protocol. One is the "European Protocol on dosimetry in mammography EUR 16263 EN from the European commission". Chapter 3 in this protocol describes in detail the determination of AGD,

Average Glandular Dose

(or MGD,

Mean Glandular Dose

). The

AGD is derived from measurements of the HVL and of the ESAK. Make use of tabulated conversion factors from ESAK to AGD. See Average Glandular Dose, AGD (MGD)

123

.

5.5.2

Setting Up the Piranha for Mammography

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To set up the Piranha:

1. Power on the Piranha using the power switch. Optionally you may connect the power supply from the power outlet to the USB port.

2. Make sure that the image receptor is positioned at a clinically relevant distance

(typically 600 mm).

3. You should place the Piranha flat on the image receptor with its long axis parallel to the chest wall making sure the centre of the detector surface is placed in the centre of the light field, as shown in the pictures above (40 mm distance shown).

This placement of the Piranha makes the detector surface perpendicular to the cathode/anode axis, to avoid influence from the heel effect.

For general mammography, it is important that the USB port points in the patients left direction, as shown in picture.

To be able to get comparable results, please consider the position of the

Piranha. The Piranha should be placed at a clinically relevant distance from the chest wall. Recommendations for this varies, typically between 40 and 60 mm. For Europe,

60 mm is the recommended distance (Ref. ECR 16263 EU).

4. Connect the devices.

Handheld

: For Bluetooth (wireless) nothing is needed.

PC

: connect the USB cable. For Bluetooth (wireless) attach the Bluetooth adapter to the PC (if not built-in).

5. Power on the handheld computer or the PC.

Now everything is set up with the hardware. Please continue in one of the following sections, depending on what you want to measure.

5.5.3

kVp, Time, and Dose Measurements with the Internal detector

Set up the Piranha and the handheld computer according to the description in Setting Up the Piranha for Mammography.

In this picture the Piranha is placed to minimize the influense of the heel effect of the tube.

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1. Select Type of Measurement and Parameter, as shown below.

If you use the compression paddle, make sure that you use the correct settings, see section Corrections for the Compression Paddle

120

.

2. Select the correct radiation (beam) quality. The radiation quality is shown in the lower right corner.

3. Make a

Position Check

, as shown above. It is recommended to make the check at

28 kV. After the check the Piranha automatically changes back to the previously selected kV range.

4. Set kVp and mAs (or mA/time) to the desired values.

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5. Make an exposure. The RTI logo flashes to indicate that the Piranha has detected the exposure.

6. Read the values in the RTD.

7. Repeat measurement for other generator set values.

There are some mammographic units that are bit peculiar when it comes to kV measurements, for instance The Hologic Selenia and IMS Giotto. In those cases, RTI have updated Application Notes, and there may be some even for other units. Please check the RTI Electronics website ( www.rti.se

) for the latest info. For Sectra MDM, Fischer Senoscan and other scanning beam units, please see the section Scanning Beam Mammography

124

.

5.5.4

Dose Measurements with the Piranha Dose Probe

It is often more convenient to use the Piranha to measure dose for a mammography tube since no manual energy compensation has to be done, as is the case with the Piranha Dose Probe.

Measuring procedure

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1. Place the Piranha Dose Probe in the field and connect the cable to the Piranha input.

2. Set up the Piranha and the handheld computer according to the description in Setting Up the

Piranha for Mammography.

3. Follow the same step as for the measurements with Piranha but select

Dose

as parameter. You will also need to select the External detector.

4. Select radiation quality from the detector list.

5. Set kVp and mAs (or mA/time) to desired values.

6. Make an exposure.

7. Read the dose value. Note that the dose reading has to be corrected manually according to the Piranha Dose Probe

DETECTOR DATA manual.

You may store the correction as a

Beam Correction Factor

in a

Favourite

for a specific kV, to do the correction automatically.

8. Repeat the measurement for other generator settings.

To get a good HVL value, using the Piranha Dose Probe, you must correct it according to the tables in the Piranha Dose Probe DETECTOR DATA manual. It is often more convenient to measure HVL with the Piranha using the built-in HVL application.

5.5.5

HVL Application

HVL is calculated in the standard way using an HVL stand and a set of Aluminium filters.

Using the Piranha and the built-in HVL application is recommended since a correct HVL value is then obtained without any manual corrections.

Set up the system the same way as described above to measure dose in mammography beams. Depending of what protocol is used you can use the HVL stand or place the filters on the compression paddle.

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1. From the dose real-time display tap the

Appl

button.

2. Select

HVL

.

3. The HVL application appears.

4. Perform exposures and add filter according to the information in the HVL application.

5. When the dose value has been reduced to less than half the HVL is calculated and the graph can be selected.

5.5.6

Quick-HVL

Quick-HVL

The Piranha is able to measure HVL for mammography in one shot. Quick-HVL is available for measurements with or without compression paddle. If the parameter "

All w. HVL

" is chosen, the QABrowser will display quick-HVL values for every measurement.

5.5.7

Mammo Compensations and Corrections

Here various corrections and compensations are described, that are of special importance for mammography.

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5.5.7.1

Corrections for the Compression Paddle

The Piranha is well collimated above its small detector area, and will measure the same whether the compression paddle is placed directly on top of the Piranha or high above.

This is NOT true for an ion chamber.

A factor has been introduced which enables the Piranha to take the scattered radiation into consideration and produce measurement results as if it was an ion chamber which senses the scattered radiation directly.

When an ion chamber is placed directly below the compression paddle, a relatively constant scatter factor of 6 % is found. The factor is typical for ion chambers such as

Radcal 6M, PTW N23344, and Standard Imaging Magna 1cc.

Typically for a Mo/Mo beam energy, a 0.10 mm Al equivalent compression paddle is used. That is equal to approximately 3 mm of plexiglass (PMMA).

For W/Al beam energy, an equivalent compression paddle of 0.18 mm Al is typically used instead.

If you tap the symbol you can see these two settings under Conditions.

When comparing with typical mammographic ion chambers listed above, you should multiply the Piranha dose value with a scatter factor of 1.06 to make it measure as an ion chamber directly below the compression paddle.

More info about the correction for compression paddle can be found in Application Note

1-AN-52020-2 from RTI Electronics AB. Please also see section Angular Sensitivity,

Piranha

24

for details on sensitivity in different directions.

5.5.7.2

Normalization

A normalization function is available which enables all measurements to be virtually performed at the same distance, increasing productivity. According to European protocol (ECR 16263 EU, 1996), ESAK should be measured 45 mm above the breast support. The QABrowser supports calculation of the dose at a user set virtual distance.

An example:

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1. First readings from an exposure, where the distance from the X-ray tube to the breast support where the Piranha is placed is 650 mm.

121

2. If the Piranha is placed on the breast support, the sensitive detector surface of the Piranha is situated 16.1 mm above the breast support, which makes the distance from the tube to the detector 633.9 mm.

ESAK is measured 45 mm above the breast support and taking the detector placement into consideration, the distance from tube to the wanted measuring position is then 605 mm.

3. When the normalizing function is used it is indicated with a blue "N", as indicated in the last figure. The dose and dose rate values are then normalized to this virtual position (at 605 mm SDD).

A practical consequence of usage of the normalizing function and scatter factor is that the Piranha can be kept at the same position on the breast support all the time when data is collected for AGD.

For an ion chamber it is not quite as easy because of the scatter contribution that is not allowed during HVL measurement. The ion chamber and/or the compression paddle must be moved to support good geometry.

More info about the correction and normalization function can be found in Application

Note 1-AN-52020-2 from RTI Electronics AB.

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5.5.7.3

Beam Correction Factor

Sometimes you may want to make comparable measurements with a known mechanical setup.

Assume that you want to emulate ion chamber measurements in a particular scattering situation. Then you can set a

Beam Correction factor

to get that reading like you used to. In this case the ion chamber measures an extra 3 % from side and back-scatter. Using this factor makes the readings to be the same. It is of course important that the mechanical setup in these cases are the same. When this function is activated a red horisontal indicator will show in the top right corner of the RTD screen ( ).

You may use the

Beam Correction factor

to make compensations and corrections of various nature. Examples might be: energy corrections, angular corrections, field inhomogeneity corrections, etc. If you save this setting as a

Favourite

, you can have a quick way of repeatedly making a special measurement without any manual corrections.

5.5.7.4

Corrections for Angular Sensitivity

For mammography, the following correction table may be used at a SDD of 60 cm, if the

Piranha is placed flat on the breast support. (This assuming that the focal point is situated at the chest wall, which normally is the case.)

You can find the product version on the label on the back side of your Piranha.

Distance from chest wall

(cm)

0

1

5

6

2

4

Correction for Piranha v1.X

(%)

0

+1.9

+3.8

+7.6

+9.5

+11.5

Correction for Piranha v2.X and higher

(%)

0

+0.01

+0.06

+0.22

+0.35

+0.50

8

+15.3

+0.88

10

+19.1

+1.38

Rule of thumb for v1.X: add 2 % per centimeter from the chest wall at

60 cm SDD, i.e. for 4 cm use +8 % correction.

As seen for product version 2.X+, no correction is necessary.

You may use the

Beam Correction Factor

together with

Favourites

in Ocean or QABrowser to automatically do a specific correction. See Beam

Correction Factor

122

.

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See also Angular Sensitivity, Piranha

24

.

5.5.8

Average Glandular Dose, AGD (MGD)

The AGD (average glandular dose) is derived from measurements of the HVL and of the ESAK, entrance surface kerma (or ESE) making use of tabulated conversion factors from ESAK (or ESE) to AGD (or MGD). The tabulated data has been derived from

Monte Carlo calculations and has been verified experimentally.

To determine the AGD a standard phantom should also be used when the

ESAK (or ESE) value is measured with the Piranha (Barracuda MPD shown).

Correct measurement of the Average Glandular Dose (AGD) with the

Piranha

In most situations you can perform measurements for a mammographic unit with the

Piranha instead of a dedicated ion chamber. Since the Piranha compensates for energy dependence, the readings are in direct comparison with readings from a reference class ion chamber. When measuring the AGD you should always have the compression paddle in place (indicated with a red icon ).

Important quantities to measure

The most common measurements for a mammographic system are conducted to determine the average glandular dose (AGD). The AGD values are based on measurements of ESAK (entrance surface air kerma) and HVL. To do the measurements correctly and according to standards, the radiation detectors should be placed directly below the compression paddle. This introduces extra scattered radiation due to the compression paddle which is important to include when determining ESAK.

On the other hand, the HVL measurement should be done without any scatter contribution and with good geometry.

HVL

The Piranha is well collimated above its small detector area. Due to this fact it registers a narrower angle of the X-ray field and thus much less scattered radiation compared to an ion chamber. It has built-in good geometry and is therefore ideal for HVL measurements. Hence, the HVL filter can be placed on top of the compression paddle without any extra collimation even at close distance to the Piranha. The Piranha has a built-in HVL application which should be used to get accurate HVL readings.

In the following examples, shown below, HVL is calculated for a W/0.5 mm Al radiation quality.

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5.5.9

Mammographic Pre-pulses

Some mammography systems (e.g. GE DMR system) use a pre-pulse to determine what radiation quality to use for a specific patient.

The time elapsing between the pre-pulse and the real exposure is usually about one second. Therefore the default post-delay of 250 ms will not cover both the pre-pulse and the real exposure. To get an overview of the signal output, set the post-delay to at least

1 s and the waveform recording time to a corresponding time. It is important to cover both signals. In this measurement setup, the Piranha will add the dose from both pulses. This is OK if the radiation quality is not changed between the signals.

If the Mammography unit changes the radiation quality after the pre-pulse however, the kV and dose is affected and the pulses should be treated separately. To collect data from real exposure, set the delay (not the post-delay) to exclude the pre-pulse. When the data has been acquired, change the radiation quality to the one chosen by the system and the measured data is automatically corrected. For the time being, this feature is only present in the QABrowser software. With Ocean a new exposure has to be made with the correct radiation quality using the same delay setting.

5.5.10

Scanning Beam Mammography

When measuring on scanning beam mammographic equipment, like for instance Sectra

MDM or Fischer Senoscan, two factors are very important.

1.

You should place the Piranha flat on the image receptor. Then position it as described in section Setting Up the Piranha for Mammography

114

.

2.

Always perform a position check. This makes sure than any field imbalances are corrected for.

3.

If you use the compression paddle, make sure that you use the correct settings, see section Corrections for the Compression Paddle

120

.

Please also see the CT section for measurement tips on scanning beams.

For Sectra L30, see special application note on the RTI Electronics website

( www.rti.se

).

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5.6

Dental and Panoramic Dental

This topic will describe how to measure kVp, dose, and time for a Dental and Panoramic

Dental X-ray units using the Piranha only.

Set up the Piranha and the handheld computer according to the description in Setting

Up the Piranha 12 . To measure kVp for a dental unit is similar to measuring for a radiography units with the difference that the output level is much lower and the total filtration is normally around 2 mm Al.

The setup is straightforward and also to get the measured value. Most dental units is still single phase self-rectified and has 100 % radiation and kV ripple. In the case of one-phase dental units it is common that only the exposure time can be changed. In most cases the set tube voltage and current is fixed to about 65 kVp and 8 mA. A challenge can exist how to find a definition what measured value should be used.

Furthermore the radiation output and the kV waveform are not stable for the first 200 ms or so, because that the tube filament current in most cases is not regulated.

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The definition of both what is the true kVp and exposure time cannot be as easily determined without study the waveform and select appropriate measurement parameters as delay and window. Introducing small CCD detectors instead of film also demands carefully calibration of single phase dental systems. The tube voltage waveform is collected from 200 ms after start trig and the kVp is calculated based on the measuring window equal the remaining part of the exposure time.

The dose value is collected for the whole exposure time. If you need to change the sensitivity, delay, or/and measuring window, tap to show the settings and make your choices.

In the case of dental panoramic system the situation is somewhat different. Here the kV and radiation waveform often is very well regulated.

The challenges instead arise for the mechanical setup needed to position the detector in right position. The small and narrow field is only a few millimetres. The Piranha detector has very narrow detector area and is very thin and a special holder (optional) can be used to position the Piranha without any problem. Panoramic units that use digital detectors have much smaller detector area and magnets cannot and should not be used close to the detector area.

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Special fixation rods for the head should be placed so that they are not in the beam during the scan or can hit the detector. In most cases the control panel have a special scan mode without X-ray so the mechanical set up can be tested.

Another important issue to be aware of is that a dental panoramic system normally compensates the for the thicker penetrating neck region in the patient when it makes its scan. This means that some units actually increase its tube voltage a short moment during the scan, other use different mA or scan speeds when the scanning beam passes the neck region. Newer digital system can actually measure patients X-ray beam attenuation dynamically and change the output level automatically during the scan.

The Piranha has addressed these challenges. Since the panoramic scan has an exposure time of about 10 to 20 seconds, the Piranha is set up to continuously update the display during the scan. It is preferable to select a single parameter display and angle the Palm holder, making it easy to read the values during the scan, from a distance.

You can always trust the kV reading of a dental measurement. This is true since

Piranha can automatically detect whether the detector area is not fully uniformly radiated or not by means of the

Position Check

, and also compensates for the beam filtration during the scan.

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You can either select the tube voltage as single parameter or together with dose, dose rate, and exposure time. As complementary information an estimation of the total filtration in the beam and type of waveform are made. This features use the kVp filter

R1[4] that also is the default kV range 55 - 105 kV when the instrument is turned on.

The displayed dose value has very little energy dependence since it is automatically compensated for each exposure since the kV, estimated filtration and the waveform are measured.

5.6.1

kVp, Time, Dose, and Dose Rate

Use the same procedure as for the normal radiography measurement but select

Dental

instead of radiography and select

Tube voltage

as parameter. A 200 ms delay is default.

1. Set up the Piranha and the handheld computer according to the description in Setting

Up the Piranha 12 . Selecting one parameter mode enables you to see the measured values from a distance of several meters.

If you want to measure the exposure time in number of pulses you can do so.

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2. Place the detector on the table at the distance that is clinically relevant. As default, the kV-filter for

55 - 105 kV is selected automatically. Furthermore the

Piranha surface should optimally be placed perpendicular to the focal spot, see also Angular Sensitivity,

Piranha 24 .

129

3. It is recommended to make a check measurement to confirm that the detector area is uniformed radiated. Select a exposure time of at least 400 ms. The Piranha automatically changes back to the previous selected kV-filter after the check exposure. As default, this is radiography filter R2 indicated by a [4] on the

QABrowser screen.

4. Set the kV and mA/time (or mAs) to desired values. Select a exposure time to near

400 ms since the delay is set to 200 ms.

5. Make an exposure.

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The Piranha now first analyses the beam and displays the type of waveform. This is done once. Then the estimated total filtration is displayed.

Read the measured values from the display.

6. Repeat the measurement for other generator settings or select an application to measure further.

5.6.2

Waveforms

The example below explains why a change of delay change the value of measured kVp and the kV and radiation waveform on a one phase dental unit.

Delay = 0 ms

Delay = 200 ms Delay = 500 ms

From the study of the above three screens several conclusions can be made:

1. A stable output level is not reached until after approximately 200 to 300 ms (20 to 30 pulses for a 50 Hz main based dental unit).

2. The exposure time is depending on the definition of the trig level.

3. The kVp value in the RTD is related to selected delay and window and is several kV higher in the beginning of the exposure at the same time as the radiation level is relative low here. Therefore a delay of 200 ms is default for the Piranha.

If the signal to the detector is too low to give a correct kV value, this part of the waveform will be blank. This is the reason why only the upper parts of

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the kV waveform is displayed. To see more of the waveform, change the kV range.

5.6.3

Panoramic Systems

Use the same procedure as for the normal dental measurement but select

Panoramic

Dental

instead of radiographic and select

Tube Voltage

as parameter. A 200 ms delay is default.

1. Set up the Piranha and the handheld computer according to the description in Setting

Up the Piranha 12 . Selecting one parameter mode enables you to see the measured values from a distance of several meters.

2. Mount the Piranha and power on the

Piranha.

3. The real-time display for Tube voltage is now displayed.

4. It is strongly advised to make Position

Check to confirm that the detector area is uniformed irradiated if you want reliable kVp readings. Select the

Check[C]

filter and leave the room to make the first panoramic scan.

5. Start the exposure. You do not need to use the whole scan exposure to make a

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check measurement since the display is continuously updated during the scan. When the value is stable within 1.00 ±0.05 release the exposure button.

If the QABrowser tells you

Reposition Detector

, please move the detector to the centre of the beam and try again.

You may need to use a film or other beam alignment tools if the narrow beam is several mm outside the expected centreline. The dental film image below shows that in the bottom part of the image you can see a part of X-ray slit image.

In this case the radiation beam centre is about 4 mm from the centre line indicated by the thin centre black line. Move the detector about 4 mm to get it in the beam was the cure for this case, to be able to pass check measurement criteria.

6. Press the rewind button on the panoramic unit to take back the unit to start position after each scan that not make a successfully check. When the system passes the test, you can trust the kV reading.

7. The Piranha changes automatically back to the previous selected kV range after the

Position Check

. As default this is range 55 - 105 kV, R2[4] as indicated on the

QABrowser screen.

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8. Press the rewind button on the panoramic unit to take back the unit to start position.

9. Select kV, mA, and scan time.

10. Start the scan. A little triangle in the RTD indicates that the Piranha detects the radiation. It is not needed to use the whole scan for the purpose of measure the kV since the display is continuously updated.

11. Stop the panoramic dental unit. The RTI logo flashes and the last kVp value is displayed. As complementary information the estimated total filtration is measured as well as the scan time.

The figure shows the RTD after a complete scan.

The waveform is also automatically stored after the delay time in the beginning of the scan or acquired when

Hold

is activated during the scan.

5.6.4

HVL, Total Filtration, and Quick-HVL

It is not unusual that the total filtration is as low as 2.0 mm Al on an dental unit, compared to 2.5 to 3.5 mm on an normal radiography unit. The method that the Piranha uses to estimate the total filtration in the range of 1.2 to 38 mm has an absolute inaccuracy in order of ±0.3 mm, but is very straightforward to find an "unknown" filter in the beam. You can always use the standard HVL method adding extra filter in the beam.

In that case, use the same procedure as described in the section for the normal radiography measurement.

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CT

5.7.1

CT kVp

To measure kVp on a CT is many times difficult since with most meters it is required to stop the tube in the top position at the same time as the table is not moving. This can normally not be obtained using an available standard clinical program. Instead a service mode must be used. Another problem is to "find" the beam, especially when using a small slice width. All these problems are minimized when using the Piranha since it can

"move with the table" through the beam while the tube is in the top position. This is can easily be obtained by measuring while a topogram (scout/pilot image) is taken. A topogram is obtained with a moving table and a stationary tube, normally in the top position. The topogram is normally used to provide information for the actual CT scan. It is recommended to use a slice width of 3 mm or wider. That is, if selectable use as large slice width as possible.

You may also want to use the

Timed

mode to allow measurements on moving CT machines, see section Update Modes

75

.

To measure CT kVp:

1. Set up the Piranha and the handheld computer according to the description in

Setting Up the Piranha

12

.

2. Place the detector on the patient bed in a region that is irradiated during the topogram process. Place the Piranha in the direction indicated by the figure below. That is, the

Piranha detector surface rectangle should be placed perpendicular to the scanning direction.

You may use the lasers to align the Piranha correctly.

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3. Start the QABrowser and select

CT

from the

Select type of measurement menu.

4. Select

Tube voltage

.

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5. The real-time display for tube voltage is now shown. At the bottom of the screen you can select kV range and calibration. Three different calibrations are available:

C1 = W/3.0 mm Al

C2 = W/3.0 mm Al + 0.25 mm Cu (optional)

C3 = W/3.0 mm Al + 1.2 mm Ti (optional)

In earlier software versions, the Piranha could not measure total filtration in the CT application. Therefore, an extra radiation quality

(C2) corresponding to measurements inside a phantom, was necessary in order to get a correct kV. Now this is taken care of automatically, since the total filtration is measured also for CT.

2: C3 is a special calibration for kV only. You cannot measure TF and HVL with it. For workaround see FAQ at RTI's webpage.

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6. First make a check of the position of the

Piranha by using the

Position Check

function.

Tap the kV range and select

Check[0]

.

7. Set up the CT to make a topogram.

8. Start the topogram program. If the procedure includes more than one topogram you may abort after the one taken with the tube in the top position.

If the Piranha is positioned in a correct way, the position is accepted and the real-time display is shown again. If not check the position of the Piranha and/or increase the slice width if possible.

9. You are now ready to measure. Repeat the topogram program to measure kVp.

The exposure time you measure is not related to the actual "radiation time". It is the time it takes for the detector to "pass through" the CT

X-ray field when the table moves when it is acquiring the topogram.

5.7.2

Parameters for CT Scanner Models

The Piranha kV CT calibrations are specified as follows:

C1 = W/3.0 mm Al

C2 = W/3.0 mm Al + 0.25 Cu (optional)

C3 = W/3 mm Al + 1.2 mm Ti (optional) (for Siemens Somatom Definition 32 and similar)

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With the calibration C1 the total filtration can be measured and the Piranha automatically corrects the kV value accordingly. It is optional to set a known total filtration instead, see the table below. To achieve optimal measurements of the total filtration, first perform a measurement at a low kV, preferable 80-100 kV. The measured total filtration is displayed on the screen. Press "Keep" to store the value and carry on with measurements. Now you can be certain to have a correct total filtration and kVvalue throughout the measurements. Further information about the total filtration can be found in section HVL & Total Filtration

83

or in the Application Note 1-AN-52020-14 from RTI Electronics AB, see your product CD or www.rti.se

.

Essential for correct measurements are correct settings of the CT. The book "Radiation

Exposure in Computed Tomography" by H.D. Nagel, contains useful information about how correct settings are done on different types of CT scanners. A computer application

CT-Expo based on the book may also be of great help. CT-Expo is an MS Excel application written in Visual Basic used to calculate patient dose values resulting from

CT examinations. The program is applicable for all existing scanner models and can be of assistance to make correct settings.

References

1. Nagel, H. D. Radiation Exposure in Computed Tomography. Fundamentals, Influencing parameters, Dose Assessment, Optimisation, Scanner Data, Terminology. 4th Edition,

Hamburg, Germany, December 2002, CTB Publications, D-21073 Hamburg, [email protected]

2. Stamm, G., Nagel, H. D. Software CT-Expo, Medizinische Hockschule Hannover, D-30625

Hannover, [email protected]

5.7.3

Quick-HVL and Total Filtration

Use the same procedure as for the normal radiography measurement, however see section CT kVp

134

about using the topogram program.

5.8

Tube Current Probes

The mAs probes are used to measure mAs (current time product) and mA (tube current). Tube current is normally measured only for fluoroscopy or when long exposure times are possible to allow read-out during the exposure. When tube current is presented for exposures it has been calculated from the measured mAs and from measured exposure time.

For pulsed fluoroscopy it is possible to measure pulse mA in addtion to the mA value.

The difference between the pulse mA and the traditional mA is explained in the picture below.

(Note that for DC waveform, pulse mA and mA gives the same value.)

You can measure mAs as a single parameter or multi-parameter together with the

Piranha. When using only the mAs-probe the measurement always starts when the mAs-probe detects a signal. When using multi-parameter you can choose to trig individually or to trig with the Piranha:

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Tube Current Probes

Individually

: The mAs-probe starts to measure as soon as the tube current is detected. The Piranha starts to measure as soon as it detects the radiation. Normally will the mAs-probe start to measure first since tube current first charges the HV cables before it "reaches" the tube and radiation is generated.

Piranha

: Both the mAs-probe and the Piranha starts to measure at the same time; when the Piranha detects radiation. This is the easiest way to measure since there is almost no risk for false triggering.

It is important to be aware of that measured mAs-values may differ depending on which trig method is used. Especially when measuring low mAs values the difference may be significant when comparing the two methods or comparing to "traditional" mAs meters.

The value you get when triggering on the tube current (Individual trig) corresponds to the total mAs supplied from the generator. A part of that has been used to charge the cables and the rest has reached the tube and contributed to the exposure and the image. When you use Piranha trig you measure only the mAs that actually contributes to the exposure and the generation of the image.

The discussion above is generally true for the invasive MAS-1 probe since it is connected in the transformer and measures "all" current. The non-invasive probes,

MAS-2 and MAS-3, can be placed anywhere on the HV cable. If they are placed close to the tube they will measure only the current that floats through the tube and contributes to the radiation and the choice of trig source will have limited influence on the measured values.

When measuring on fluoroscopy the trig source has no influence and it is recommended to trig on the Piranha.

5.8.1

MAS-1, Invasive mAs Probe

This section describes how to measure the tube current and charge as a single parameter. This means that the measurement starts when the mAs-probe detects the tube current. The measurement is performed in the same way if you use a multiparameter display. In that case the default trig is the Piranha and what is said below about false triggering can be ignored.

The MAS-1 probe provides an invasive way to measure mA and mAs on X-ray generators. The MAS-1 probe should be connected to the X-ray generator mAs socket. The figure to the left shows the

Piranha MAS-1 Probe. Read the MAS-

1User's Manual for a detailed description on how to connect it.

To measure tube charge (mAs) with the Piranha MAS-1 Probe

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1. Connect the MAS-1 probe to the X-ray generator as described in the MAS-1 User's

Manual.

2. Connect the MAS-1 probe to the external probe input.

3. Set up the Piranha and the handheld computer according to the description in Setting

Up the Piranha

12

.

4. In the QABrowser select type of measurement.

5. Select

mAs

from the menu.

6. The real-time display for mAs is now displayed. Set the generator. Tap

Reset

.

Make an exposure.

7. The figure to the left shows the result from an exposure with 80 kV, 50 ms, and

100 mA. The exposure time is measured with the external probe input.

If you would get a message as shown in the figure to the left, the current is floating in the wrong direction in the mAs probe. Switch the two connectors that are connected in the mAs measuring socket, tap

Reset

and make a new exposure.

Since the MAS-1 probe is connected in the X-ray generator false triggering may occur due to electrical noise when the pre-heat is started and the anode starts to rotate. If you get incorrect or inconsistent results try the following:

First start anode rotation without firing the exposure.

While the anode is rotating do a

Reset

or press the corresponding button. Make the exposure when the reset procedure is finished.

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8. Tap

Wave

to view that mA waveform.

The figure to the left shows the mA waveform. You can use the cursor to analyse the waveform and read the mA value as well as estimate the exposure time.

The MAS-1 probe can also be used for measurement of tube current during fluoroscopy.

To measure fluoroscopy tube current with the Piranha MAS-1 Probe

1. Setup the Piranha according to the description earlier in this manual.

2. Connect the MAS-1 probe to the X-ray generator as described in the MAS-1 User's

Manual.

3. Connect the MAS-1 probe to the external probe input.

4. In the QABrowser select type of measurement.

5. Select

Tube Current

from the menu.

6. The real-time display for tube current is now displayed. Set the generator. Do a

Reset

.

7. Start the fluoroscopy.

8. The figure to the left shows the real-time display during fluoroscopy. The tube current is measured and the display is updated approximately every four seconds. Note that for low mA values the mAs and the exposure time may not be measured. Tap

Hold

to "freeze" current value in the display. The waveform is also acquired when Hold is activated.

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5.8.2

MAS-2, Non-invasive mAs Probe

This section describes how to measure mAs, using the Piranha in the x-ray beam to trigger the measurement. This means that the measurement starts when the Piranha detects the radiation.

The MAS-2 probe uses a current clamp probe to measure mAs and mA non-invasively.

The MAS-2 probe is mostly used for mAs measurements since it is not sensitive enough to measure tube current on fluoroscopy. The lowest tube current that can be measured with

MAS-2 is 10 mA. The figure to the left shows the MAS-2 probe without the cable.

The parameter mAs is available for most type of measurements but mAs is normally measured only for X-ray exposures.

To measure tube charge (mAs) with the Piranha MAS-2 Probe

1. Connect the MAS-2 probe to the X-ray generator. Then power on the MAS-2 by turning the range switch to the 4 A range and make a Reset of the MAS-2 probe by pressing the yellow knob on the probe.

2. Connect the MAS-2 adapter cable to the Piranha.

3. Set up the Piranha and the handheld computer according to the description in Setting

Up the Piranha

12

.

4. In the QABrowser select type of measurement.

5. Next select parameter

mAs

from the menu.

6. The real-time display for mAs is now displayed. Set the generator. Tap

Reset

. Make an exposure.

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7. The figure to the left shows the result from an exposure with 80 kV, 100 ms, and

25 mA. The exposure time is measured with the MAS-2 probe.

If you would get a message as shown in the figure to the left, the mAs probe is probably connected in the wrong direction. Change the direction of the mAs probe, press the reset button on the mAs probe, tap

Reset

,

and make a new exposure.

Since the MAS-2 probe is based on measurement of magnetic flux, false triggering may occur due to electrical noise when the pre-heat is started and the anode starts to rotate.

If you get incorrect or inconsistent results try the following:

First start anode rotation without firing the exposure.

While the anode is rotating tap

Reset

or press corresponding button. Make the exposure when the reset procedure is finished.

8. Tap

Wave

to view that mA waveform.

The figure to the left shows the mA waveform. You can use the cursor to analyse the waveform and read the mA value as well as estimate the exposure time.

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Note that we are relatively close to the lower limit for the MAS-2 probe and the signal may look "noisy". The figure to the left shows the waveform when the tube current has been increased to 100 mA.

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5.9

Light Measurement

The Piranha Light Probe is a highly sensitive light detector. It has two different adapters to measure the quantities luminance and illuminance. The most common applications for the Piranha Light Probe are luminance (cd/m²) measurements on CRTs (monitors) and viewing boxes, and illuminance (lx) measurements of ambient light in a room or in front of a CRT. Read the Piranha Light Probe User's Manual for a detailed description of practical use and explanation of the theory behind the units and quantities of light.

The monitor adapter is shown to the left and the lux adapter to the right.

5.9.1

Luminance - Monitor/Viewbox (cd/m²)

Read the Piranha Light Probe User's Manual to get information about how to do different type of measurements and how to use the different adapters.

To measure luminance (cd/m²):

1. Attach the monitor adapter to the Piranha Light Probe as described in the Piranha

Light Probe User's Manual.

2. Connect the Piranha Light Probe to the Piranha.

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3. Set up the Piranha and the handheld computer according to the description in Setting

Up the Piranha

12

.

4. In the QABrowser select

Monitor

or

Viewing box

from the Type of Measurement menu.

5. Next select parameter

Luminance

from the menu.

6. The Select Detector screen is now displayed. Select the Piranha Light Probe-M (the

M stands for monitor).

7. Tap

Select

.

8. The real-time display for luminance is now displayed. Tap

Reset

. Place the light detector on the surface where you want to measure the light.

9. Press and hold the shutter. Read the value on the real-time display. You can now move the Piranha Light Probe to other points and measure the light.

If you are measuring very low light intensities it may occur that the Piranha does not

"start" to measure. You should then do as follows:

1. Do as described in step 1 to 8 above.

2. Press and hold the shutter. If the Piranha does not start to measure, lift the Piranha

Light Probe and direct it towards a bright spot (with the shutter button pressed). Do not release the shutter button.

3. Place the Piranha Light Probe on the spot where you want to measure. Do not release the shutter button.

4. Read the result on the display. Do not release the shutter button.

5. Move the Piranha Light Probe to the next spot where you want to measure. Do not release the shutter button.

6. Read the result on the display. Do not release the shutter button.

7. Continue and do not release the shutter button.

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5.9.2

Illuminance - Ambient Light (lx)

Read the Piranha Light Probe User's Manual to get information about how to do different type of measurements and how to use the different adapters.

To measure illuminance (lx):

1. Attach the lux adapter to the Piranha Light Probe as described in the Piranha Light

Probe User's Manual.

2. Connect the Piranha Light Probe to the Piranha.

3. Set up the Piranha and the handheld computer according to the description in Setting

Up the Piranha

12

.

4. In the QABrowser select

Ambient light

from the Type of Measurement menu.

5. Next select parameter

Illuminance

from the menu.

6. The Select Detector screen is now displayed. Select the Piranha Light Probe-L probe.

7. Tap

Select

.

8. The real-time display for illuminance is now displayed. Cover the white light-sensitive area of the Piranha Light Probe to shield off all light (you may use the rubber part that comes with the Piranha Light Probe-M if available). It is very important that you shield off all light. Then tap

Reset

. After that you can remove the shield and place the light detector where you want to measure.

9. Read the value on the real-time display.

The figure to the left shows the result. You can now move the Piranha Light Probe-L to other points and measure the ambient light.

If you are measuring very low light intensities it may occur that the Piranha does not

"start" to measure. You should then do as follows:

1. Do as described in step 1 to 8 above.

2. If the Piranha does not start to measure, lift the Piranha Light Probe-L and direct it towards a bright spot.

3. Place the Piranha Light Probe detector on the spot where you want to measure.

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4. Read the result on the display.

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Optional Accessories

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6. Optional Accessories

6 Optional Accessories

Optional accessories and tools available for the Piranha.

6.1

Holder & HVL Stand

Measuring HVL using the classic method? Then the Piranha holder and HVL stand together with a filter kit may be handy. The stand features a camera screw that fits perfectly into the camera thread of the Piranha. The stand allows you to position the Piranha or the Piranha Dose Probe and HVL filters in any angle including upsidedown. Use the light-field or other help to position the Piranha in the X-ray field. The Piranha detector is not sensitive for different field sizes as long as the entire sensitive detector area is irradiated, but try to keep the field size down to minimize scattering. Recommended field size for

Piranha is 20×40 mm (at the Piranha surface).

6.2

Piranha Panoramic Holder

Measuring on an orthopantomographic dental machine may be practically difficult.

Use of the Piranha Panoramic Holder may help a bit.

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Piranha Panoramic Holder

The idea of how to use it is as follows:

149

1.

Centre the two set screws so that the holder is in its central position.

2.

Position the Holder (without the Piranha) to the X-ray output slot. Use the "pointy" shapes of the Holder (in the holes on the centre line), as shown with arrows to the left, to position it right on the slot.

3.

Fixate the Holder using the magnets or, if no magnets are allowed, adhesive tape to the surface.

4. Adjust the position in detail using the set screws.

5.

If needed use the bendable plate to fit it "around a corner", as shown below.

Magnet or tape position

Bend the included plate here

Fasten the included plate with the base with this screw.

Magnet or tape position

6.

Insert the Piranha in the Holder, lock it with the rubber strap and perform the measurement.

7.

The extra magnet may be used for hanging the USB or charger cable "out of the way".

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6. Optional Accessories

Piranha Panoramic Holder

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Problems and Solutions

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7. Problems and Solutions

7 Problems and Solutions

7.1

Troubleshooting

Before contacting your distributor or RTI Electronics, please check the following tips.

A

. Check the RTI web page for updates http://www.rti.se

.

B

. Run through the checklist below.

The Piranha does not work

Check:

1. Check that the motor moves properly or can beep. (QABrowser:

Setup | System

Test

).

The Piranha filter seem to have stuck

1. Start the QABrowser and run the filter test. (QABrowser:

Setup | System Test

)

2. Hold the Piranha in you right hand by the cable edge.

3. When the motor is trying to move, tap the Piranha's left long edge in the palm of your left hand until it comes free.

The electrometer does not give a reading

Check:

1. That the correct input connector is used and connected.

2. That probe cables look healthy.

The electrometer gives numerous trig indications

If you get the trig indicator ("play" symbol) when there is no signal:

1. Press reset.

2. If it comes over and over you may need to increase the trig level, by raising the threshold, see topic Settings

43

.

The electrometer or Piranha gives too low dose rate

If you get to low dose rate readings or too short irradiation times for short exposures:

1. Check that you are measuring with a good geometry, where the incoming radiation is perpendicular to the detector surface. See Specifications, Piranha

14

for details.

The QABrowser does not show the Bluetooth "Discovery Results" screen

Try the following:

1. Exit the QABrowser.

2. Do a hardware reset of your Tungsten (using the reset hole on the back of the

Palmtop).

3. Restart the QABrowser.

A HotSync was performed to install a new version of QABrowser but it does not seem to have been installed

The reason can be that wrong Palm user name has been used.

1. Open Palm Desktop and select edit users in the upper right corner.

2. Tap the HotSync icon on the Palm, the user name can be seen in the upper right corner.

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3. If the user name is not in the list in Palm Desktop, perform a HotSync to automatically add the user name. If it is in the list, go to number 4.

4. Restart the QABrowser Updater and select the Palm user name corresponding to the Palm that you intend to use.

Installation or upgrade of RTI Updater failed

Make sure you are not having a restricted user account (on Windows XP, 2000, or newer). You will need to have access to an administrative account to install the software, see section Windows Restricted User Accounts for details.

My Piranha cycles its status indicator quickly between colours and does not measure

Your system is in Bootloader mode. Please run RTI Updater to correct this.

My Piranha beeps twice quickly when starting

The Piranha normally beeps once when starting. If it beeps twice quickly when powering on, run RTI Updater to correct this.

I get a blank white screen when running the QABrowser

Click the Back button (leftmost) to get out and then re-enter the test again.

Bluetooth unable to reconnect using Retry

Tap

Exit

and restart the Piranha and then re-start the QABrowser again.

Bluetooth only shows "Unknown device" when trying to connect

Depending on Palm model it may take a little while for the serial number to appear, the

Piranha will appear as "Unknown device". Normally it will show the serial number if you wait a while.

How do I change from Gray to Röntgen units?

You can set this for all tests (

pull-down menu | Setup | Units

), see Units Setup

64

.

It is also possible to set mixed units for a test and save as Favourites

59

. All measurements settings, QABrowser settings, set values, and selected units will be saved with the Favourite.

How do I stop the units from autoscaling its prefixes?

There is a preference setting for this (

pull-down menu | Setup | Preferences

), see

Preferences Setup

65

.

Can I set the time before the Handheld powers off automatically?

Yes, there is a preference setting for this (

pull-down menu | Setup | Preferences

), see Preferences Setup

65

.

How do I reset the Handheld computer?

There is a small reset hole on the back of the Handheld computer, use the stylus

(pointer) to reset.

How do I use Bluetooth with Windows Vista?

Please see the following section on Bluetooth Passkey

154

.

C

. Contact your local representative or see Notice for contact information to RTI

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Troubleshooting

Electronics AB. The more information you supply will help us to get a quick solution to your problem. Examples of useful information is screen dump pictures, exact error message texts, log files, etc. You may also use the auto-report function described in the section How To Report a Problem

156

.

7.2

Bluetooth

Bluetooth is a wireless way of communication between your PC/handheld and your meter. The Piranha has built-in support for this, but with the Barracuda you need the

Barracuda Serial Bluetooth Module

accessory. A Palm OS handheld also has built-in support for Bluetooth but a PC may or may not have built-in support for Bluetooth. If the

PC does not have built-in Bluetooth support you will need a Bluetooth adapter (that you connect to the USB port) for instance the D-Link DBT-120 or DBT-122.

The range of Bluetooth is about 10 meters (32 feet) in free air for a class 2 Bluetooth adapter (like the D-Link DBT-122), for a class 1 Bluetooth adapter (like the Targus

ACB20EU) the theoretical range is up to 100 metres. This can be significantly shorter if there are walls and other objects obstructing the signal.

Bluetooth and a Palm OS handheld works out of right out of the box, while using

Bluetooth and PC usually requires some work. If it is possible for you to use a USB cable with your PC and meter then this is recommended.

7.2.1

Bluetooth Passkey

There are two different ways to use Bluetooth with you meter, without a passkey and with a passkey (also called PIN code, authentication, and Bluetooth security code). All meters and accessories that are delivered from RTI Electronics from the first quarter of

2010 are configured to use a passkey (0000).

Drawbacks of using a Passkey

If you enable a passkey you might experience some drawbacks.

If you use your meter (with Bluetooth communication) with more than one PC or with a PC and a Palm OS handheld you might need (depending on your hardware) to add the meter (also called to pair a device, or to add as a trusted device) with the PC/ handheld every time you have used another PC or handheld with the meter.

With a Palm OS handheld you cannot just simply start the QABrowser with Bluetooth.

You need to first add the meter as a trusted device. And if you have used the meter with another handheld or PC (using Bluetooth) you will need to add the meter as a trusted device again.

New hardware which supports multiple devices

Piranha with product version 3.0 (which started shipping around spring 2009) and higher, and product version 2.5.4 supports multiple Bluetooth devices, which means that you can use it with both a PC and handheld without additional steps.

Advantages of using a Passkey

Works with Windows Vista and Windows 7-8.

Increased security

The main reason to change so that you use a passkey is if you are going to use

Bluetooth communication and Windows 7-8, Vista, or Windows XP and a Bluetooth

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adapter where you cannot disable authentication. But we recommend that you use a

USB cable if you can.

If you want to use a passkey and have previously not been using one, you need to reconfigure your Piranha/Barracuda Serial Bluetooth module. Detailed instructions are available later on in this manual.

Bluetooth Passkey and Palm OS

If your meter is configured to use a Bluetooth passkey you need to add the meter as a trusted device before you can use it with your handheld. Due to a problem in Palm OS this requires that you perform some additional steps.

If you have already launched the QABrowser and you are asked for a passkey then you can enter the following passkey: 0000. With some hardware the handheld might ask for the passkey again (and again), then you can do one of the following:

1. Enter the passkey (0000) again, and again (will usually work after five times).

2. Cancel after it asks for the passkey the second time, cancel the next window

(

Connecting...

), and then you will be presented with the Bluetooth device list again.

This time your meter will have a key next to it and it will work properly.

3. Quit the QABrowser (by for instance a soft reset) and add the meter as a trusted device. It is recommended that you do this before you launch the QABrowser after having used the meter with Bluetooth and another device (handheld/PC).

Add as a Trusted Device on Palm OS

If you have not yet launched the QABrowser you can do the following:

1. Launch

Prefs

.

2. Select

Bluetooth

. Depending of the Palm model this is either available directly on the screen or as a drop-down option in the upper right corner of the display.

3. On some Palm OS models you now need to click

Setup Devices

, on other models a

Trusted

Devices

button is available in this screen.

4. Click the

Trusted Devices

button.

5. If you have already added your device before, then remove it by selecting it, then click the

Details...

button, and then click

Delete Device.

6. Click

Add Device

and select your meter from the list.

7. When prompted for a passkey enter 0000.

8. Now launch the QABrowser as described above.

If your Piranha/Barracuda hardware does not support multiple Bluetooth devices (see above), and you use Bluetooth (with passkey) with more than one handheld, or if you are using Bluetooth with a handheld and a PC you will need to re-add the meter as a trusted device whenever you have used it with another PC or handheld (using a

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Bluetooth

Bluetooth connection).

7.2.2

Enable Bluetooth Passkey

Before you enable the use of a Bluetooth passkey please read the section about

Bluetooth passkeys and the drawbacks of using a passkey.

You enable and disable passkeys by using the

RTI Updater

application (requires version 2008.6A or later) which is available on your RTI Software & Documentation CD and the RTI website ( www.rti.se

).

1. Connect your meter using the USB cable. If you are using a Barracuda then also connect the Barracuda Serial Bluetooth Module.

2. Launch RTI Updater from the RTI Electronics folder in the Windows start menu.

3. Select the USB connection. You cannot use a Bluetooth connection when you want to change the Bluetooth configuration. A Bluetooth connection is shown as

COMxx

.

4. Wait for RTI Updater to finish with the startup procedure. After a while when it is ready the

Start

button will be enabled.

5. Select

Settings | Advanced

from the menu.

6. Now select the

Tools

menu.

7. If you want to enable the use of a passkey select

Enable Bluetooth Passkey

. If you experience problems with this, then you probably need to update you meter firmware before you can enable the Bluetooth passkey. Please run the available updates (by pressing

Start

) and then restart the application again to enable the Bluetooth passkey.

8. Follow the onscreen instructions.

If you want to disable the Bluetooth passkey do the same thing but select

Disable

Bluetooth Passkey

instead. If you are asked for a PIN code during the startup do

not

enter a PIN code, just cancel instead. Because if you do, you will have activated your

Bluetooth and RTI Updater cannot reconfigure the Bluetooth module when it is active.

7.3

How To Report a Problem

There is a way of automatically sending technical support information to RTI Electronics

AB when you are experiencing problems with the QABrowser.

This is how you use that functionality:

1. HotSync the Palm handheld that you are experiencing the problem with.

2. On your PC, go to

Start Menu | All Programs | RTI Electronics | QABrowser

Updater

and click

Send Support Information

.

3. A dialogue window will be shown. Please enter a description of the problem.

The more information you give, we will have better chances of reproducing the problem and finding a solution to it.

4. Click

Send

to send the auto-generated email.

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8. Glossary

8 Glossary

Absorbed dose (D)

The energy imparted per unit mass by ionizing radiation to matter at a specified point.

The SI unit of absorbed dose is joule per kilogram (J/kg). The special name for this unit is gray (Gy). The previously used special unit of absorbed dose was the rad. 1 rad =

0.01 Gy. 1 Gy = 100 rad. (See Report No. 82, NCRP, 1985b.)

SI unit: Gy = J/kg

Absorbed dose rate (D')

absorbed dose per unit time. Absorbed dose rate is determined as the quotient of dD by dt, where dD is the increment of absorbed dose in the time interval dt: D'=dD/dt. A unit of absorbed dose rate is any quotient of the gray or its multiples or submultiples by a suitable unit of time (Gy/s, mGy/h, etc.).

SI unit: Gy/s = J/kg·s

Absorption, energy

Phenomenon in which incident radiation transfers to the matter which it traverses some or all of its energy.

Activity

The number of nuclear transitions occurring in a given quantity of radioactive material per unit time. The SI unit of activity is s

-1

. The special name for the unit of activity is becquerel (Bq). The previously used special unit of activity was the curie (Ci). 1 Bq = 2.7

x 10

10

Ci. 1 Ci = 3.7 x 10

10

Bq. (See Report No. 82, NCRP, 1985b.)

SI unit: Bq = s

-1

Additional filtration

ADDED FILTERS and other removable materials in the RADIATION BEAM which are between the RADIATION SOURCE and the PATIENT or a specified plane.

See also filter.

Air kerma

See kerma.

Aluminium equivalent or Aluminium Attenuation Equivalent (AAE)

The thickness of aluminum affording the same attenuation, under specified conditions, as the material in question.

Anode

In a X-ray tube, electrode to which electrons forming a beam are accelerated and which usually contains the target.

Aperture

(e.g., for computed tomography) - the opening in the collimation that allows radiation to reach the detector.

Area exposure product

Product of the area of a cross-section of a radiation beam and the averaged exposure over that cross-section.

SI unit: Gy·m²

Attenuation

The reduction of radiation intensity upon passage of radiation through matter.

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Automatic exposure control (AEC)

In an X-ray generator, mode of operation in which one or more loading factors are controlled automatically in order to obtain at a preselected location a desired quantity of radiation.

Automatic exposure rate control

In an X-ray generator, mode of operation in which the rate of emitted radiation is controlled automatically by control of one or more loading factors in order to obtain at a preselected location and in a preselected loading time a desired quantity of radiation.

Beam limiting device

Device to limit the radiation field.

Becquerel (Bq)

The special name for the SI unit of activity. One becquerel is one reciprocal second or 1 s

-1

. 3.7 × 10

10

Bq = 1 Ci.

Bootloader

General: a program that does the job of loading the OS kernel of a computer.

Piranha bootloader: Miniature program stored in cabinet and modules which normally just starts the Firmware. It is used more when the Firmware is updated. See Firmware.

Centigray

0.01 gray. 1 cGy equals one rad.

Cinefluorography

The production of motion picture photographic records of the image formed on the output phosphor of an image intensifier by the action of X-rays transmitted through the patient (often called cineradiography).

Cineradiography

Indirect radiography of moving objects usually in rapid series on cine film.

Collimator

See beam limiting device.

Compensating filter

Filter used in order to modify the distribution of absorbed dose rate over the radiation field.

Computed tomography (CT)

An imaging procedure that uses multiple X-ray transmission measurements and a computer program to generate tomographic images of the patient.

Continuous mode

For an X-ray generator, mode of loading an X-ray tube continuously as in radiotherapy or in radioscopy.

Conversion factor (of an image intensifier)

The quotient of the luminance of the output phosphor of the image intensifier divided by the kerma rate at the input phosphor.

SI unit: cd/m² / Gy/s = cd·s/Gy·m²

CT

See Computed Tomography

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CT number

One of a set of numbers on a linear scale which are related to the linear attenuation coefficients calculated by a computed tomographic device. One of the specific set of CT numbers on a scale from -1000 for air to +1000 for bone, with water equal to zero, which is called a Hounsfield unit.

Curie (Ci)

The previously used special unit of activity equal to 3.7 × 1010 per second. 1 Ci =

3.7 × 10

10

Bq.

Dead man switch

A switch so constructed that a circuit-closing contact can be maintained only by continuous pressure on the switch.

Dental panoramic radiographic

Direct radiography of a part of or the complete dentition by the use of an intra-oral X-ray tube. See also Orthopantomography.

Diagnostic source assembly

A diagnostic source housing (X-ray tube housing) assembly with a beam limiting device attached. This assembly shall be so constructed that the leakage radiation air kerma measured at a distance of one meter from the source does not exceed 1 mGy (0.1 rad) in one hour when the source is operated at its leakage technique factors. (See definition).

Digital radiography

A diagnostic procedure using an appropriate radiation source and an imaging system which collects processes, stores, recalls, and presents image information in a digital rather than analogue fashion.

Digital subtraction

An image processing procedure used to improve image contrast by subtracting one digitized image from another.

Dose equivalent (H)

A quantity, defined for radiation protection purposes, which is the product of the absorbed dose to the tissue and a quality factor "Q" determined by the properties of the radiation that produced the absorbed dose. For X-rays, gamma rays, and electrons, Q =

1 and dose equivalent values are numerically equal to absorbed dose values when consistent units are used for both quantities. The SI unit for dose equivalent is joule per kilogram. The special name for the SI unit of dose equivalent is sievert (Sv). The previous special unit of dose equivalent was the rem. One sievert equals 100 rem.

SI unit: Sv = J/kg

Dose rate meter

Radiation meter intended to measure absorbed dose per unit time.

Dosemeter

Radiation meter intended to measure absorbed dose.

Effective dose equivalent (HE)

Quantity used to express the weighted DOSE EQUIVALENT to the whole body when it is irradiated non uniformly or partially.

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Exposure (X)

A measure of the quantity of X-ray or gamma radiation based upon its ability to ionize air through which it passes. The SI unit of exposure is coulomb per kilogram. The previously used special unit of exposure was röntgen (R). 1 R = 2.58 × 10

-4

C·kg

-1

(exactly). The physical quantity exposure is now replaced by the quantity kerma in air. An exposure of 114.1 R is equal to an Air Kerma of 1 Gy. That means that the value in R should be multiplied by 8.76 to get the Air Kerma in mGy.

SI unit: C/kg

Exposure rate (X')

Exposure per unit time. Exposure rate is determined as the quotient of dX by dt, where dX is the increment of exposure in the time interval dt: X' = dX/dt. A unit of exposure rate is any quotient of the unit of exposure or its multiples or submultiples by a suitable unit of time ((C/kg)/s, (mC/kg)/h, etc.).

SI unit: C/kg·s

Filter

In radiological equipment, material or device provided to effect filtration of the radiation beam.

SI unit: mm

Filter: Inherent filter

The filter permanently in the useful beam; it includes the window of the X-ray tube and any permanent enclosure for the tube or source. Replaced by term Permanent filter

Filter: Added filter

Filter in addition to the inherent filtration.

Filter: Permanent filter

The filter permanently in the useful beam; it includes the window of the X-ray tube and any permanent enclosure for the tube or source.

Filter: Total filter

The sum of the permanent and added filters.

Firmware

General: The operating system and software installed on a small device. Sometimes called embedded software.

Piranha firmware: Program stored in cabinet and modules which handles all control of measurement electronics. Can be updated, then a special part of the firmware called bootloader, is used. See Bootloader.

Fluorography

The production of a photographic record of the image formed on the output phosphor of an image intensifier by the action of X-rays transmitted through the patient.

Fluoroscopy

Technique of radioscopy by means of a fluorescent screen.

Focal spot, effective

The apparent size of the radiation source region in a source assembly when viewed from the central axis of the useful radiation beam.

SI unit: dimensionless (corresponding to a dimension in mm)

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Framing

In cinefluorography, the registration of the circular image of the output phosphor on the rectangular film element or frame.

Gantry

The moveable patient table used for CT.

Geometric unsharpness

Unsharpness of the recorded image due to the combined optical effect of finite size of the radiation source and geometric separation of the anatomic area of interest from the image receptor and the collimator.

Gray (Gy)

The special name for the SI unit of absorbed dose, kerma, and specific energy imparted equal to one joule per kilogram. One gray equals one joule per kilogram. The previous unit of absorbed dose, rad, has been replaced by the gray. One gray equals 100 rad.

Half-value layer (HVL)

Thickness of a specified substance which, when introduced into the path of a given beam of radiation, reduces the kerma rate by one-half.

SI unit: mm

Heel effect

Non-uniform intensity observed because a small fraction of the X-ray beam emitted in a direction nearly parallel to the angled target surface must pass through more target material before escaping from the target than does the major portion of the beam which is emitted more perpendicularly. (Note: In addition to the non-uniform intensity the angled target also produces non-uniform image resolution due to variations in apparent focal spot size as viewed from various positions on the film).

Hounsfield units

See CT number.

Image intensifier

An X-ray image receptor which increases the brightness of a fluoroscopic image by electronic amplification and image minification.

Image receptor

A system for deriving a diagnostically usable image from the X-rays transmitted by the patient. Examples: screen film system; stimulable phosphor; solid state detector.

Inherent filtration

Filter between the radiation source and the output window of the X-ray equipment.

See filter.

Initial X-ray tube voltage

In a capacitor discharge X-ray generator, X-ray tube voltage at the beginning of the loading of the X-ray tube.

Installation

A radiation source with associated equipment, and the space in which it is located.

Interlock

A device used to assure proper and safe use of a radiation installation by monitoring

(usually by electrical devices) the status, presence or position of various associated

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devices such as source position, collimator opening, beam direction, door closure, filter presence, and preventing the production or emission of radiation if the potential for an unsafe condition is detected.

Ionization

Formation of ions by the division of molecules or by the addition or removal of electrons from atoms or molecules.

SI unit: C, Coloumb

Ionization chamber

Ionization detector consisting of a chamber filled with a suitable gas, in which an electric field, insufficient to induce gas multiplication, is provide for the collection at the electrodes of charges associated with ions and the electrons produced in the sensitive volume of the detector by ionizing radiation.

Ionization constant

For air the ionization constant W/e = 33,97 J/C. The ionization constant is used to get the correspondence between exposure and air kerma. See Roentgen and Gray for more information.

Ionization detector

Radiation detector based on the use of ionization in the sensitive volume of the detector.

Irradiation time

Irradiation time is usually the time a rate of a RADIATION QUANTITY exceeds a specified level. Irradiation time is sometimes called Exposure time.

SI unit: s, second

Kerma (K)

The sum of the initial kinetic energies of all the charged ionizing particles liberated by uncharged ionizing particles per unit mass of a specified material. Kerma is measured in the same unit as absorbed dose. The SI unit of kerma is joule per kilogram and its special name is gray (Gy). Kerma can be quoted for any specified material at a point in free space or in an absorbing medium. Typically the kerma is specified in air.

SI unit: Gy = J/kg

Kerma rate (K')

Kerma per unit time. Kerma rate is determined as the quotient of dK by dt, where dk is the increment of kerma in the time interval dt: K'=dK/dt. A unit of kerma rate is any quotient of the Gray or its multiples or submultiples by a suitable unit of time (Gy/s, mGy/h, etc.).

SI unit: Gy/s = J/kg·s

Kilovolt (kV)

A unit of electrical potential difference equal to 1000 volts.

kVp

See Peak tube voltage

Lead equivalent

The thickness of lead affording the same attenuation, under specified conditions, as the material in question.

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Leakage radiation

All radiation coming from within the source assembly except for the useful beam. (Note:

Leakage radiation includes the portion of the radiation coming directly from the source and not absorbed by the source assembly, as well as the scattered radiation produced within the source assembly).

Magnification imaging

An imaging procedure carried out with magnification usually produced by purposeful introduction of distance between the subject and the image receptor.

Measured value

Estimate of the true value of a quantity, derived from the indicated value of a meter after applying all relevant correction factors.

Medical diagnostic radiology

Medical diagnosis using ionizing radiation.

Modulation transfer function (MTF)

A mathematical entity that expresses the relative response of an imaging system or system component to sinusoidal inputs as a function of varying spatial frequency, which is often expressed in linepairs per millimetre (lp/mm), the correct unit is however m

-1

(or often mm

-1

). The reference value most commonly used is that for zero frequency. The

MTF can be thought of as a measure of spatial resolution of the detector system.

SI unit: m

-1

Monitor, personnel

See personnel monitor.

Occupancy factor (T)

The factor by which the workload should be multiplied to correct for the degree of occupancy (by any one person) of the area in question while the source is in the "ON" condition and emitting radiation. This multiplication is carried out for radiation protection purposes to determine compliance with the dose equivalent limits.

Operator

Any individual who personally utilizes or manipulates a source of radiation.

Orthopantomography

Orthopantomography (also called OPG or Panorama) is a radiographic procedure that produces a single image of facial structures including the upper and lower dentition jaws and their supporting structures and bones. Mostly used in dental applications. An OPG

("orthopantomogram") gives a panoramic view of the mouth, giving information on the teeth and the bones of the upper and lower jaw.

Particle fluence

Number of particles incident on a sphere, divided by the cross-sectional area of the sphere.

SI unit: m

-2

Personnel monitor

Also known as personal monitor. An appropriately sensitive device used to estimate the absorbed dose received by an individual.

Peak tube voltage Ûo (kVp)

The peak value of the tube voltage (corresponding to the highest available radiation

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energy).

Phantom

In medical radiology, object behaving in essentially the same manner as tissue, with respect to absorption or scattering of the ionizing radiation in question. Phantom are used, for example, for simulating practical conditions of measurement:

- for purposes of radiation protection,

- for evaluating the performances to the diagnostic systems with respect to the radiation or to the object,

- for dosimetry.

Pixel

A two-dimensional picture element in the presented image.

Practical Peak Voltage (PPV)

The PPV is the constant potential producing the same image contrast as the waveform under test. PPV is defined in the IEC 61676 standard as: "The PRACTICAL PEAK

VOLTAGE is based on the concept that the radiation generated by a high voltage of any waveform produces the same AIR KERMA contrast behind a specified PHANTOM as a radiation generated by an equivalent constant potential. The constant potential producing the same contrast as the waveform under test is defined as PRACTICAL

PEAK VOLTAGE".

Primary protective barrier

See protective barrier

Protective apron

An apron made of radiation absorbing materials, used to reduce radiation exposure.

Protective barrier

A barrier of radiation absorbing material(s) used to reduce radiation exposure.

Protective glove

A glove made of radiation absorbing materials used to reduce radiation exposure.

Rad

The previously used special unit of absorbed dose. It is equal to 100 ergs per gram. 1 rad = 0.01 Gy (10

-2

gray).

Radiation (ionizing)

Any electromagnetic or particulate radiation capable of producing ions, directly or indirectly, by interaction with matter. Examples are X-ray photons, charged atomic particles and other ions, and neutrons.

Ripple factor

The variation in the high-voltage expressed as the percentage of the maximum highvoltage across the X-ray tube during X-ray production: Ripple factor (%) = 100 x (Vmax

- Vmin)/Vmax

Radiation protection survey

An evaluation of the radiation safety in and around an installation, that includes radiation measurements, inspections, evaluations, and recommendations.

Radiation receptor

Any device that absorbs a portion of the incident radiation energy and converts this portion into another form of energy which can be more easily used to produce desired

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8. Glossary

results (e.g., production of an image). See image receptor.

Radiation source

The region and/or material from which the radiation emanates.

Radiogram

A film or other record produced by the action of X-rays on a sensitized surface.

Radiography

The production of images on film/image detector by the action of X-rays transmitted through the patient.

Receptor

See radiation receptor.

Receptor assembly

A radiation receptor in the specialized container necessary for the proper operation of the receptor.

Rem

The previously used special unit of dose equivalent. One rem equals 10

-2

sievert (Sv).

Resolution

In the context of an image system, the output of which is finally viewed by the eye, it refers to the smallest size or highest spatial frequency of an object of given contrast that is just perceptible. The intrinsic resolution, or resolving power, of an imaging system is measured in mm

-1

or line pairs per millimeter (lp/mm), ordinarily using a resolving power target. The resolution actually achieved when imaging lower contrast objects is normally much less, and depends upon many variables such as subject contrast levels and noise of the overall imaging system.

Roentgen (R) (or Röntgen)

The previously used special unit of exposure. 1 R = 2.58 × 10

-4

C/kg. – Originally

(Stockholm 1928) defined as "international R." (Symbol: r) and later (Chicago 1937) modified to: Roentgen- or -ray, that gives a charge of 1 esE from secondary emission in 0,001293 g of air.

This means that an exposure of one Roentgen will produce 2,58 × 10

-4

coulomb of ions of either sign per kilogram in air. Here the previously used physical quantity exposure has been replaced by kerma in air. See kerma. One R does not equal 1 cGy as the units C/kg and J/kg are different. To do this conversion the ionization constant for air must be used, which is 33,97 J/C. This is how its calculated: 1 Gy = 1 J/kg Û 1 J/kg/

(2,58 × 10

-4

C/kgR × 33,97 J/C) = 114,1 R. An exposure of 114,1 R thus equals an Air

Kerma of 1 Gy. That also means that the value in R should be multiplied by 8,76 to get the Air Kerma in mGy. (See also Exposure.)

Scattered radiation

Radiation that, during passage through matter is changed in direction. (It is usually accompanied by a decrease in energy.)

Serial radiography

A radiographic procedure in which a sequence of radiographs is made rapidly by using an automatic cassette changer, image intensifier/TV chain, etc.

Shutter

In beam therapy equipment, a device, attached to the X-ray or gamma-ray source

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housing to control the "ON" or "OFF" condition of the useful beam.

8. Glossary

167

Sievert (Sv)

The special name for the SI unit of dose equivalent. One sievert equals one joule per kilogram. The previously used unit was the rem. One sievert is equal to 100 rem.

Signal-to-noise ratio

For video cameras, the ratio of input signal to background interference. The greater the ratio, the clearer the image.

Simulator

Diagnostic energy X-ray equipment used to simulate a therapy treatment plan outside the treatment room.

Slice

The single body section imaged in a tomography procedure.

Source

See radiation source.

Source-detector distance (SDD)

The distance measured along the central ray from the centre of the front surface of the source (X-ray focal spot or sealed radioactive source) to the active surface of the detector.

Source-to-image-distance (SID)

The distance measured along the central ray from the centre of the front of the surface of the source (X-ray focal spot of sealed radioactive source) to the surface of the image detector.

Source-surface distance (source-skin distance) (SSD)

The distance measured along the central ray from the centre of the front surface of the source (X-ray focal spot or sealed radioactive source) to the surface of the irradiated object or patient.

Spot film

A radiograph taken during a fluoroscopic examination for the purpose of providing a permanent record of an area of interest of to verify the filling of a void with contrast media.

Stray radiation

The sum of leakage and scattered radiation.

Survey

See radiation protection survey.

Target

The part of an X-ray tube anode assembly impacted by the electron beam to produce the useful X-ray beam.

Tenth value layer (TVL)

Thickness of a specified substance which, when introduced into the path of a given beam of radiation, reduces the kerma rate to one-tenth of its original rate.

Tomography

A special technique to show in detail images of structures lying in a predetermined

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8. Glossary

plane of tissue, while blurring or eliminating detail in images of structures in other planes.

Topogram

For CT, prior to making the cross-sectional scans, the CT scanner is normally used to obtain one or more radiograph-like reference images, as a way of identifying and documenting where the scans are to be made. These so-called topograms are prepared by keeping the X-ray source and the detectors stationary, and dragging the specimen through the fan-beam by moving the table. Also called scout scans, pilot scans, or scanograms.

Total filtration

The total of inherent filtration and additional filtration.

Useful beam

The radiation which passes through the opening in the beam limiting device and which is used for imaging or treatment.

User

Physicians and other responsible for the radiation exposure of patients.

Voxel

A volume element in the object being imaged. The mean attenuation coefficient of the voxel determines the CT (Hounsfield) number of the pixel.

Whole body dose equivalent (Hwb)

The dose equivalent associated with the uniform irradiation of the whole body.

Workload (W)

The degree of use of a radiation source. For X-ray machines operating at tube potentials below 500 kV, the workload is usually expressed in milliampere minutes per week. For gammabeam therapy sources and for photon-emitting equipment operation at

500 kV or above, the workload is usually stated in terms of the weekly kerma of the useful beam at one meter from the source and is expressed in grays per week at one meter.

Xeroradiography

The production of an image on a xerographic plate (e.g., electrically charged selenium) by the action of X-rays transmitted through the patient. (xeromammography:

Mammography carried out by the xeroradiographic process.)

X-ray tube

Evacuated vessel for the production of x-radiation by the bombardment of a target, usually contained in an anode, with electrons accelerated from a cathode by an electric field. Thus: Rotating anode X-ray tube. Double focus X-ray tube.

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Index

Note!

Page references in this Index points to the first page of the section it is mentioned, not the exact page.

- 2 -

2002/96/EC 29

- A -

About 5

Absorbed dose 158

Absorption 158

Accessories 148

Piranha holder & HVL stand 148

Active display messages 78

Active Messages 65, 78

Activity 158

Add as trusted device, Bluetooth 155

Additional filtration 158

Additional filtration (mammo) 47

Advantages of using a Passkey 154

AEC 158

After exposure 75

After exposure update mode 48

AGD 117, 123

Air kerma 158

Air kerma (Dose) 16, 17, 19

Air kerma rate (Dose rate) 16, 17, 19

Aluminium equivalent 158

Ambient light 145

AMX-4 46

Analogue Out 88, 96

Analyse waveform 65

Anode 158

Anode/Filter combination 113

Mo/Mo 113

Mo/Rh 113

Rh/Rh 113

W/Rh 113

Aperture 158

Application

HVL 95, 118

Applications 52

Multi-parameter 55

Single-parameter 53

Authentication, Bluetooth 154

Auto prompt 65

Auto reset 74, 75

Automatic exposure control 158

Auto-power off 152

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Index

Autoscaling 152

Average Glandular Dose 117, 123

169

- B -

Battery charging 67 charging times 13 indicator 67 level 10, 13, 67 running time 10, 13 status 10, 67 warning 67

Battery charging indicator 10

Beam Correction 69

Beam Correction Factor 48, 122

Beam limiting device 159

Beam quality 38, 89, 113

Becquerel 159

Blank screen 152

Bluetooth 37, 152, 154

Indicator 9

Passkey 154

Passkey advantages 154

Passkey and Palm OS 155

Passkey disadvantages 154

PIN code advantages 154

PIN code disadvantages 154

Security code 154

Bootloader 32, 159

Built-in applications 52

- C -

Calibrations

View 35

Camera thread 9

CAS-6 12

CAS-7 12 cd/m² 143

CE Declaration 30

Intended Use 31

CE Mark 30

Centigray 159

Change

Unit of measure 38

Charging Batteries 67

Charging Times 13

Checking battery status 67

Chest wall distance 113

Cine 101, 103

HVL 103

Quick-HVL 103

Total filtration 103

Cine/Pulsed exposure

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Index

Cine/Pulsed exposure

Default settings 74

Cinefluorography 159

Cineradiography 159

Collimator 159

Communication

Bluetooth 13

USB 13

Compensating filter 159

Compensation 89

Compliances 29

Compression paddle 47

Equivalent thickness 43, 120

Compression paddle indicator 69

Computed tomography 134

Computed tomography (CT) 159

Conditions 43, 45, 89

Conformity Declaration 30

Connector

External probe 9

Palm charging 9

USB 9

Connectors 9

Continuous 75

Continuous mode 159

Continuous update mode 48

Conversion

HVL to TF 83

TF to HVL 83

Conversion factor (of an image intensifier)

159

CT 134, 159

Calibration 136

Default settings 74 kVp 134

Quick-HVL 137

Total filtration 137

CT Dose Profiler 28

CT number 159

CT specifications 19

CT topogram 134

CTDI values

Typical 136

CT-DP 28

CT-Expo software 136

Curie (Ci) 159

Current waveform 42

- D -

Data logging 57

Dead man switch 160

Declaration of Conformity 30

Default settings 74

Default Unit 152

Piranha & QABrowser Reference Manual

Delay 50, 52, 74, 82, 130

Start efter 48

Waveform 48

Delay time 80

Deleting a Favourite 60

Demo 37

Dental 125

Default settings 74

HVL 133

Quick-HVL 133

Total filtration 133

Dental panoramic 131

Dental panoramic radiographic 160

Dental specifications 16

Dental waveforms 130

Detector 38

Detector area 14

Detector Information 66

Detector Manager 35

Detector settings 52

Detector surface 9

Detectors

Managing 35

Viewing 35

Diagnostic source assembly 160

Digital radiography 160

Digital subtraction 160

Direct radiography of a part of or the complete dentition by the use of an intra-oral X-ray tube. See also

Orthopantomography. 160

Disable Bluetooth passkey 156

Display messages 78

Active 78

Passive 80

Distributing Favourites 60

Dose 94

Mammography 117

Dose equivalent (H) 160

Dose Probe 9

Dose Probe Specifications 26

Dose rate meter 160

Dose Sensitivity 50

Dose/Pulse 19, 102

Dosemeter 160

Drawbacks of using a Passkey 154

Drop-down menu 68

- E -

Effective dose equivalent (HE) 160

Electrometer waveform 42

Enable Bluetooth passkey 156

Entrance Skin Exposure 117, 123

Entrance Surface Air Kerma 117, 123

Equivalent thickness

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Equivalent thickness

Compression paddle 43, 120

Error 152

Error messages 78

ESAK 117, 123

ESE 117, 123

Estimated total filtration 16, 17, 19

EU Directive 29, 30

Exclamation indicator 69

Exp. < Delay 80

Exposure (X) 160

Exposure rate (X') 160

External probe connector 9

- F -

Favourites 59, 68

Delete 60

Distribute 60

Getting Started 60

Save 60

FCC 32

Filter 161

Filter: Added filter 161

Filter: Inherent filter 161

Filter: Permanent filter 161

Filter: Total filter 161

Filtration Additional(mammo) 47

Firmware 5, 32, 161

Fluorography 161

Fluoroscopy 103, 161

Default settings 74

Dose rate 106

HVL 106, 108 kVp 106

Quick-HVL 108

Total filtration 108

Fluoroscopy specifications 16

Focal spot, effective 161

Framing 161

Free run 75, 77

Free run update mode 48

Using 77

- G -

Gantry 162

Geometric unsharpness 162

Good geometry

HVL 120

Gray (Gy) 162

- H -

Half Value Layer

Theory 83

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Half-value layer (HVL) 162

Handheld Reset 152

Heel effect 12, 162

Help 89

High kVp 78, 80

High signal 78, 80

Hold indicator 68

Holder 148

Piranha 12

HotSync 37, 57, 70, 152

Hounsfield units 162

House Icon 68

How To

Report a Problem 156

HVL 83, 95

Application 95

Cine 103

Dental 133

Fluoroscopy 108

Good geometry 120

Stand 12, 95, 148

Index

171

- I -

IEC 61267 21

II dose rate 104

Illuminance 145

Image intensifier 104, 162

Image receptor 162

Indicate trig 65

Indicator

Battery charging 9

Bluetooth 9

Status 9

Indicators

Battery level 67

Beam Correction 69

Compression paddle 69

Exclamation indicator 69

Hold 68

Logging active 68

Measurement 38

Normalize 69

Pause 68

Play 68

RTD 38

Trig 68

Warning 69

Waveform indicator 69

Inherent filtration 162

Initial X-ray tube voltage 162

Input dose rate 104

Installation 162

Intended Use 31

Interlock 162

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Index

Internal detector settings 43, 50

Introduction 5

Ionization 162

Ionization chamber 162

Ionization constant 162

Ionization detector 162

Irradiation time 16, 17, 19, 82, 162

ISO 4037 21

- K -

Kerma 163

Kerma rate 163

Kilovolt (kV) 163 kV Sensitivity 50 kVp 16, 17, 19, 163 kVp waveform 42

- L -

Lead equivalent 163

Leakage radiation 163

Light

Default settings 74

Light measurment 143

Light probe 145

Light Probe Specification 28

Linearity 85

Lock unit prefixes 65

Log 65

Logging 57

Logging indicator 68

Low battery warning 67

Low kVp 78, 80

Low Signal 78, 80

Luminance 143 lux 145 lx 145

- M -

Magnification imaging 164

Maintenance 32

Mammography 113

Default settings 74

Dose 117

HVL Application 118

Positioning Piranha 113

Quick-HVL 119

Mammography specifications 17

Manufacturer's Declaration of Conformity

30 mAs 138, 141

MAS-1 Probe Specifications 28

MAS-2 Current Probe 141

MAS-2 Probe Specifications 28

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Mean Glandular Dose 117, 123

Measured value 164

Measurement 101, 110

Cine 101

Dental 128

Dose 94

Dose per pulse 101, 110

Fluoroscopy 103

Image intensifier 104

Mammography 115

Number of pulses 101

Panoramic dental 131

Pulse rate 110

Pulsed fluoroscopy 110

Pulsed radiography 101

Radiography 89, 91, 97

Measurement Modes

Overview 74

Measuring principle

Piranha 83

Medical diagnostic radiology 164

Menu icon 68

MGD 117, 123

Min. output peak dose rate 19

Minimum pulse width 19

Minimum ripple 19

Mo/Mo Anode/Filter combination 113

Mo/Rh Anode/Filter combination 113

Modes

Of Measurement 74

Modulation transfer function (MTF) 164

Module 38

Monitor 143

Monitor, personnel 164

Moving average 77

- N -

Negative Signal 80

Normalization distance 43, 120

Normalize indicator 69

- O -

Occupancy factor (T) 164

Operating air pressure 14

Operating temperature 14

Operator 164

OPG 125

Optional Accessories 148

Orthopantomography 148, 164

Oscilloscope 88, 96

Overview of Measurement Modes 74

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- P -

Palm computer requirements 6

Palm OS and Bluetooth Passkeys 155

Panoramic 131

Panoramic dental 125

Panoramic Dental (OPG)

Default settings 74

Panoramic Holder 148

Particle fluence 164

Passive display messages 80

Passkey advantages 154

Passkey and Palm OS, Bluetooth 155

Passkey drawbacks, Bluetooth 154

Pause indicator 68

PC requirements 6

Peak tube voltage Ûo (kVp) 164

Personnel monitor 164

Phantom 164

Physical dimensions

Piranha 15

PIN code advantages 154

PIN code drawbacks, Bluetooth 154

PIN code, Bluetooth 154

Piranha 12, 83

Cable 12

Holder 12

Mammography positioning 113

Physical dimensions 15

Piranha holder & HVL stand 148

Specifications 14

Piranha holder 148

Piranha internal detector 83

Piranha Light Probe 143, 145

Piranha MAS-1 Probe 138

Piranha position check 38

Piranha settings 43, 48

Pixel 164

Play indicator 68

Position check 101, 115, 124 of Piranha 38

Post delay 48, 74, 82

Power Management 67

Power supply 67

Power switch 9

PPV 38

PPV waveform 42

Practical Peak Voltage 38

Practical Peak Voltage (PPV) 164

Preferences 65

Prefixes

Lock 65

Prefixes, Unit 152

Pre-pulse mammography 124

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Index

Primary protective barrier 164

Probes

Managing 35

Viewing 35

Problem Report 152, 156

Protective apron 164

Protective barrier 164

Protective glove 164

Pulse Measurements 102

Pulse Rate 19, 46, 102

Pulsed fluoroscopy 103, 110

Default settings 74

Pulsed radiography 101

- Q -

QABrowser 37

Setup 63

Uninstallation 72

Updating 70

Quick-HVL

Cine 103

CT 137

Dental 133

Fluoroscopy 108

Mammography 119

Radiography 99

- R -

Rad 165

Radiation (ionizing) 165

Radiation protection survey 165

Radiation quality 21, 38

Radiation receptor 165

Radiation source 165

Radiation time 82

Radiogram 165

Radiography 91, 97, 99, 165

Default settings 74

Quick-HVL 99

Total filtration 99

Radiography specifications 16

Real-Time Display 37, 38

Receptor 165

Receptor assembly 165

Recording time 74, 75

Reference conditions 14

Regulations 64

Rem 165

Report a Problem 156

Reposition Detector 80

Reproducibility 86

Requirements, Palm computer 6

Requirements, PC 6

173

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Index

Reset

Bluetooth 152

Handheld 152

Piranha 38

Reset time 75

Resolution 165

Retry 37

Rh/Rh Anode/Filter combination 113

Ripple factor 165

Roentgen (R) (or Röntgen) 165

Röntgen Unit 152

RTD 38

Indicators 38

RTI Detector Manager 35

RTI Updater 32

Running time 10, 13

- S -

Safety strap 9

Saving a Favourite 60

Scanning Beam Mammography 124

Scatter factor 43, 120

Scattered radiation 166

SDD

Normalization 43, 120

Search button 69

Select

Beam quality 38

Detector 38

Module 38

Unit of measure 38

Send Support Information 156

Sensitivity 50, 52

Dose/TF 50 kV 50

Serial number 38

Serial radiography 166

Settings 50, 52, 69, 89

Beam correction factor 48

Compression paddle 47

Conditions 43, 45

Delay 50, 52

Detector 52

Internal detector 43, 50

Piranha 43, 48

Post delay 48

Pulse rate 46

Sensitivity 50, 52

Threshold 50, 52

Total Filtration 45

Trig level (time) 48

Trig source 48

Update mode 48

Waveform recording time 48

Piranha & QABrowser Reference Manual

Waveform type 45

Window 50, 52

Setup

Log 65

Power Management 67

Preferences 65

QABrowser 63

Regulations 64

System Info 66

System Test 66

Units 64

Shutter 166

Sievert (Sv) 166

Signal Extension Module 88, 96

Signal-to-noise ratio 166

Simulator 166

Size 15

Sleep time 65

Slice 166

Source 166

Source-detector distance (SDD) 166

Source-surface distance (source-skin distance) (SSD) 166

Source-to-image-distance (SID) 166

Specifications

Air kerma (Dose) 16, 17, 19

Air kerma rate (Dose rate) 16, 17,

19

Battery Charging 13

Bluetooth 13

Communication 13

CT 19

Dental 16

Dose Probe 26

Dose/pulse 19

Estimated total filtration 16, 17

Fluoroscopy 16

Irradiation time 16, 17, 19 kVp 16, 17, 19

Light Probe 28

Mammography 17

MAS-1 Probe 28

MAS-2 Probe 28

Min. output peak dose rate 19

Minimum pulse width 19

Minimum ripple 19

Piranha 14

Power Source 13

Pulse rate 19

Radiography 16

Size 15

USB 13

Waveform recording time 20, 27

Weight 15

Spot film 166

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Stand 12

Standards and Compliances 29

Start 32

Start after delay 48

Start Here! 59, 63

Starting the QABrowser 37

Status indicator 9

Stay on in Cradle 65

Storage temperature 14

Stray radiation 166

Support 152

Support Information 156

Survey 166

Symbols 68

System Info 66

System Test 66

- T -

Target 167

Tenth value layer (TVL) 167

TF 83

TF Sensitivity 50

Theory

Current reading 82

Delay 82

Dose rate reading 82

Half Value Layer 83

Irradiation time 82

Linearity 85

Post delay 82

Radiation time 82

Reproducibility 86

TF and HVL conversion 83

Total Filtration 83

Waveform 82

Window 82

Threshold 50, 52

Timed 75, 76

Timed update mode 48

Using 76

Tomography 167

Topogram 134, 167

Total filtration 45, 83, 89, 91, 97, 167

Cine 103, 108

CT 137

Dental 133

Fluoroscopy 108

Radiography 99

Trig

Visual indication 65

Trig indicator 68

Trig level (time) 48

Trig source 48

Trigger 82

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Index

Troubleshooting 152

Trusted device, Bluetooth 155

Tube current

Invasive 138

Non-invasive 141

Tube current measurements 137

Typical CTDI values 136

Typical Response 21

Typographical Rules 5

- U -

Uninstallation

QABrowser 72

Unit

Default 152

Gray 152

Prefixes 152

Röntgen 152

Unit of measure

Change 38

Units 64, 152

Unknown device 152

Update Firmware 32

Update Mode 48, 74, 76, 77

Update modes 75

Update of Piranha 32

Updating

QABrowser 70

Upgrading 70

USB connector 9

Useful beam 168

User 168

175

- V -

View Calibrations 35

Viewbox 143

Voxel 168

- W -

W/Rh Anode/Filter combination 113

Warning indicator 69

Waste Electrical and Electronic

Equipment 29

Waveform 82

Activating 65

Dental 130

Waveform delay 48

Waveform indicator 38, 69

Waveform recording time 48, 74, 75

Waveform recording time Specifications

20, 27

Waveform type 45, 91, 97

Waveforms 42

WEEE 29

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Index

Weight 15

White screen 152

Whole body dose equivalent (Hwb) 168

Window 50, 52, 82

Window time 80

Workload (W) 168

- X -

Xeroradiography 168

X-ray tube 168

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Notes

Notes

177

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Piranha & QABrowser Reference Manual

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