User manual | Unit tates Patent [191

Unit
tates Patent [191
Hui-a
[54]
[75]
[73]
[21]
RADlATllON COLLIMATOR
Inventor: Michael Hura, Wickliffe, Ohio
Assignee: Picker Corporation, Cleveland, Ohio
Appl. No.: 19,083
[22] Filed:
[51]
[52]
[58]
4,246,188
[45]
Jan. 20, 11.981
[57]
ABSTRACT
A compact and light weight radiographic collimator
including two pairs of radiation absorbent shutters con
nected together by a parallelogram linkage which pro
vides a nested arrangement when the shutters are in
their full open position yet provides an aligned relation
Mar. 9, 1979
Int. (31.3 ........................ .. G21F 5/04; G21K 1/04
11.5. C1. ................................... .. 250/513; 250/511
Field of Search ............. .. 250/511, 510, 512, 513,
250/514, 505, 402
[56]
[11]
References Cited
ship when fully closed. An off-focal vane construction
in which the vanes are moved reciprocally is also dis
closed.
The shutters and vanes may be either manually or auto
matically adjusted. Manual adjustment is automatically
limited to the maximum safe open position.
2,887,586
5/1959
Reiniger ............................. .. 250/491
3,023,314
2/1962
l-lura
3,502,872
3/1970
Norgren
3,643,095
2/1972
Shuster
250/511
A collimator adjusting drive train using constantly
meshing gearing and a slip clutch is employed. A series
of ?lter plates of varying thicknesses are provided. The
operator can select the ?ltration desired by positioning
each ?lter plate in either its ?ltering or non?ltering
3,678,233
7/1972
Faw et al.
250/510
position and then insert the stack of plates into a slot. A
3,767,931
10/1973
3,829,701
8/1974
Hura
3,980,407
9/1976
Hill ..................................... .. 250/511
U.S. PATENT DOCUMENTS
....t....
Williams
. . . ..
250/511
250/511
. .. . . .
........
. . . ..
250/505
sensor provides an indication of when the ?lter assem
. . . ..
250/513
bly is positioned in the collimator.
Light beam centering and ?eld size indication are pro
Primary Examiner-Alfred E. Smith
Assistant Examiner-Thomas P. O’Hare
Attorney, Agent, or Firm-Watts, Hoffmann, Fisher &
Heinke Co.
vided from a single light source.
16 Claims, 15 Drawing Figures
U
Patent
Jan. 20, 1981
Sheet 1 0f 8
494% 9 1 LL 1
64
U, Pawn
Jan. 20, 1981
Sheet 2 of 8
346,4
U.”
mm
Jan. 20, 1981
Sheet 4 of8
,26,48
/ Ax/s OF BEAM 2/
BOUNDARY 0F '
56AM 2/
Um
amt
Jan. 20, 1981
Sheet 5 of8
499M
505
US". Pamm
Jan. 20, 1981
Sheet 6 Of8
4,246,488
WE” Patent
Jan. 20, 1981
-
Sheet7 0f8
4,246,48?
1
4,246,488
2
In either event, it is necessary to counterbalance the
DIATION COLLIMATOR
REFERENCE TO RELATED PATENTS
1. US. Pat. No. 2,887,586, issued May 19, 1959 to W. 5
G. Reininger, entitled “X-Ray Focusing Apparatus”,
weight of the collimator. In addition, especially with a
collimator within the table, it is not only desirable that
the collimator be light weight but also important that it
be compact.
SUMMARY OF THE INVENTION
herein the CENTERING PATENT.
The collimator made in accordance with this inven
2. US. Pat. No. 3,023,314, issued Feb. 27, 1962 to
Michael I-Iura, entitled “X-Ray Apparatus”, herein the
tion is highly compact and light weight. A major factor
in achieving compactness is that one set of the dia
COLLIMATOR PATENT.
3. US. Pat. No. 3,502,872 to Edwin A. Norgren,
phragms comprises two pairs of radiation absorbent
shutters connected together by a parallelogram linkage
entitled “Automatic Shutter Control for an X-Ray Spot
Filmer”, herein the AUTOMATIC ADJUSTMENT
PATENT.
4. US. Pat. No. 3,829,701, issued Aug. 3, 1974 to
Michael Hura, entitled “Radiation Collmator”, herein
the OFF-FOCUS PATENT.
which provides a compact, out-of-the-way nested ar
rangement when the shutters are in their full open posi
tion yet provides an aligned relationship when fully
closed to completely block a beam from emergence
from the collimator.
Another aspect of the invention that contributes to
BACKGROUND OF THE INVENTION
the compactness of it is an off-focal vane construction in
20 which the vanes are moved reciprocally rather than
1. Field of the Invention
This invention relates to medical X-ray apparatus and
pivotally as has been the case with the prior art, permit
more particularly to an improved radiographic collima
ting the dimension of the collimator axially of the beam
tor.
to be shorter than has been the case previously.
In medical diagnostic studies with X-rays a beam of a
A further feature of the collimator of this invention is
desired size and cross-sectional con?guration is delin 25 that shutters may be either manually or automatically
eated by a device known as a collimator. Typically a
adjusted. If there is manual adjustment to a position in
radiographic collimator has adjustable longitudinal and
which the diaphragms are too far open for a given ?lm
transverse sets of X~ray absorbent diaphragms which
size and source-to-image distance, the shutters are auto
control the so-called ?eld size, that is the transverse
matically driven inwardly to the maximum safe open
30
con?guration and dimension of, an X-ray beam.
position.
-
A major consideration in medical X-ray diagnosis is
A novel arrangement for obtaining both manual and
automatic drive is provided. A drive train using con=
to minimize the radiation dosage administered to a pa
tient during any given radiographic study. Accordingly
it is important that when a radiographic exposure is to
stantly meshing gearing is employed. The drive train
provide exposure of a sheet of X-ray ?lm but to avoid
caused to slip with manual adjustment while it also
be made, the collimator diaphragms are positioned to 35 includes a slip clutch which can be relatively easily
provides a reliable automatic drive connection. Thus,
unlike prior devices, manual adjustment is accom
plished without rotating the motor used in automatic
an oversized ?eld size. That is radiation should not pass
through the patient in regions around or at least adja
cent to the ?eld of interest because such radiation does
adjustment.
not produce any diagnostic information.
Another feature of the invention is the provision of a
The delineation of a beam of appropriate size is com
novel and simpli?ed ?ltering arrangement. A main and
supplemental ?lter plates of varying thicknesses are
of X-rays and the imaging device is a variable. As an
provided. Each supplemental ?lter plate has an aperture
X-ray tube is moved toward a ?lm of a given size, the
apex angles of a given rectangular beam must be en 45 and a ?ltering and non?ltering position. The operator
can‘ select the ?ltration desired by positioning each
larged if the entire sheet of ?lm is to be exposed. Con
supplemental ?lter plate in either its ?ltering or non?l
versely, the apex angles must be reduced when the
tering position and then insert the stack of plates into a
X-ray tube is moved away from the ?lm or a patient will
slot. Thus, the ?lters not being used are stored in the
receive needless extra dosage because the beam is larger
same location as when they are in use for ?ltration in a
in cross-sectional dimension in the plane of the ?lm than
very compact and simple arrangement.
is necessary to expose the ?lm. 2. Description of the
plicated by the fact that the distance between the source
In addition, a sensor provides an indication of when
Prior Art
Proposals have been made for automatically varying
diaphragm settings to control ?eld size as source-to
image distance (SID) varies. One such proposal is dis
55
the ?lter assembly is, and when it is not, appropriately
positioned in the collimator. When the ?lter assembly is
not appropriately positioned in the collimator either
closed in US. Pat. No. 3,502,872 to Edwin A. Norgren,
entitled “Automatic Shutter Control for an X-Ray Spot
Filmer”.
because it is absent or not fully and properly inserted,
Appropriate diaphragm setting is a function not only
the ?ltration assembly is in and properly seated, higher
operation of the associated X-ray tube is automatically
limited to a kilovoltage level of 50 Kv maximum. Once
of the SID but also of the size ?lm which is to be used. 60 energy levels can be employed. This system obviously
protects the patient against exposure to excessive radia
Accordingly, sensors are provided in a Bucky tray, as
tion should an operator fails to properly insert the ?lter
an example, to sense the size of a ?lm cassette in the
assembly in the collimator.
tray, provide electrical signals to a collimator control so
One important feature of the invention is the mechan
that the beam settings are of appropriate size for the ?lm
in the tray.
65 ical mounting and movement of the off-focus and in
Collimators are typically mounted on X-ray tubes
focus diaphragms. In the preferred embodiment, the
which are suspended from the ceiling by a ceiling tube
off-focus diaphragms are mounted for movement trans
amount or alternately supported within an X-ray table.
verse the direction of X-ray propagation. No pivotal
3
4,246,488
mount is needed so that most effective X-radiation con
trol and collimation is achieved. The transverse dia
phragm motion provides greater ?eld ?exibility and
allows more compact diaphragm vane design.
Apparatus is provided for co-ordinating movement of
the collimator diaphragms with the source to image
X-ray distance. Standards have been adapted with the
4
FIG. 15 is a- schematic diagram of an electrical con~
trol.
DESCRIPTION OF THE PREFERRED
EMBODIMENT
Referring to the drawings and to FIG. 5 in particular,
an X-ray apparatus is shown including an X-ray tube
housing 10 which supports and houses an X-ray tube 12.
The X-ray tube 12 includes an anode 14 having a focal
spot 16 which is bombarded by electrons to cause the
emission of X-radiation.
A collimator 20 is supported by a tube housing 10 and
optimum diaphragm positioning to provide maximum
functions to delineate an X-ray beam 21 of rectangular
?eld coverage.
cross-section. The collimator 20 includes a housing 22
Certain convenience features are also included in the
collimator system. A light centering feature enables the 5 and a mounting assembly 70 for connecting the collima
tor housing 22 to the tube housing 10.‘
user to see the extent of the ?eld as well as the center of
A vane and shutter mechanism, including on and off
that ?eld. This enables the user to carefully position the
focus assemblies 102, 104, is disposed within the colli
X-ray tube in relation to the patient. Dials are included
mator housing 22 for delineating the perimeter of the
on the collimator which inform the user of pertinent
beam. A drive assembly 300' controls the position and
data such as the source to image distance and the extent
movement of the vane and shutter mechanism. A cen
of the ?eld to be exposed.
tering light assembly 360 provides an indication during
From the above it should be apparent that one object
collimator adjustment of the size and location of a colli
of the invention is to provide an automatic system for
mated X-ray beam to be produced. A ?lter assembly
controlling the radiation ?eld size according to industry
440
is provided for attenuating radiation.
wide standards. A second object is to provide an im
I. The Collimator" Housing 22
proved design and method for co-ordinating the move
Referring to FIGS. 1-4, the collimator housing 22
X-ray apparatus industry for proper ?eld size depend~
ing upon the distance the patient is removed from the
source. The present invention provides a technique for
sensing the source to image distance and providing
ment of both in-focus and off-focus collimator dia
phragms. Other features and objects of the invention
will become understood when the detailed description
is considered in conjunction with the accompanying
drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevational view of an X-ray collima
tor constructed in accordance with the invention;
FIG. 2 is a side elevational view of the collimator of
FIG. 1, showing the right side, as viewed in FIG. 1;
FIG. 3 is a rear elevational view of the collimator of
FIG. 1;
FIG. 4 is a top plan view of the collimator of FIG. 1;
de?nes spaced input and output end openings 24, 26.
The housing includes a front panel 28, a rear panel 30,
and side panels 32, 34. The input end opening 24 is
surrounded by the mounting assembly 70. An off ?eld
portion of the vane and shutter assembly projects from
the housing 22 through the input end opening 24. The
output end opening 26 includes a bottom window 36
(FIG. 5) having crosshairs indicated in an expanded and
schematic manner at 37. Tlie crosshairs functon as an
aid to locations of the collimator 20, and the X-ray tube
12, with respect to a patient.
The front ‘panel 28 carries controls and signalling
devices to carry out and indicate the various collimator
functions, see FIG. 1. It is important that the distance
FIG. 5 is a cross-sectional view of the collimator as
from the X~ray tube to the plane of an X-ray ?lm, or
other imaging device, be know with reasonable accu
racy. As the X-ray tube 12 is brought closer to the
FIG. 6 is alrear view on a reduced scale, of the colli 45 X-ray ?lm and, the patient, the area of the beam 21
mator with its housing with transverse vanes removed
should be increased to cover the entire imaging device.
for clarity;
It is also important that the beam size is not too large to
FIG. 7 is a view of the collimator as viewed from the
avoid excessive irradiation of the patient.
plane indicated by the line 7—7 of FIG. 1 with certain
With the collimator of the present invention, adjust
seen from the plane indicated by the line 5——5 of FIG. 1,
and a schematic representation of an X-ray tube;
components removed for clarity of illustration;
SO ments are available from a zero ?eld size, that is with
FIG. 8 is a cross-sectional view of the positioning
the X—ray beam fully blocked, to a maximum opening of
light assembly with parts broken away and removed for
90 cm. square. Since the maximum ?eld size which is
appropriate is a function of the X-ray source to image
clarity;
FIG. 9 is an elevational view of a vane and shutter
distance (SID) it is important for the operator to know
drive assembly as seen from the plane indicated by the
line 9-9 of FIG. 5;
FIG. 10 is a side elevational view of the drive assem
bly as seen from the plane indicated by the line 10—10
of FIG. 9;
both the accurate SID and the ?eld size setting to which
the collimator is adjusted.
In order to accomplish this, a pair of ?eld size indica
tor discs 38, 40 (portions of which are shown in FIG. 1)
are supported for rotation adjacent the front panel 28. A
FIG. 11 is an enlarged view of a longitudinal motor 60 pair of windowed S.I.D. selector discs 42, 44 are sup
assembly as seen from the plane indicated by the light
ported for rotation behind the front panel and respec
11-11 of FIG. 9;
.
tively in front of the indicator discs 38, 40. The front
FIG. 12 is a plan view, partly in section, of the radia
panel 28 includes a pair of apertures 46, 48 through
tion ?lter sub assembly;
which portions of the discs 38, 40, 42, 44 can be viewed.
FIG. 13 is a view as seen from the plane indicated by
Rotation of the windowed S.I.D. selector discs 42, 44
the line 13_-13 of FIG. 12 showing a detent mechanism
is controlled by an S.I.D. selector knob 50 extending
employed to retain ?lter plates in position;
FIG. 14 is an exploded view of ?lter plates; and
outwardly of the front panel 28. Upon rotation of the
selector knob 50, the S.I.D. selector discs 42, 44 are
5
4,246,488
indexed at 90° intervals to locate windows correspond
ing to the selected S.I.D. in the apertures 46, 48. The
operator will see only that portion of the ?eld size indi
cator discs 38, 40 showing ?eld sizes to which the beam
be delineated for the selected S.I.D. In order for the
operator to know which S.I.D. to select a retractable
tape measure 51 is disposed within the housing 22 adja—
cent the panel and its tape is accessible at the lower
portion of the panel 28.
A pair of ?eld size selector knobs 52, 54 project out
6
swivel ring 76. The relative lateral positions of the
swivel ring 76 and the adapter 82 are adjusted by a
plurality of circumferentially spaced set screws 88.
Once the swivel ring 76 and the adapter are appropri
ately located laterally they are ?xed in place by a pair of
locking plate 90 which clamp the swivel ring 76 and the
adapter 82 together by means of fasteners 92. This a1‘
rangement provides very precise alignment of the X-ray
tube and collimator transversely of the X-ray beam to
O be delineated. A plurality of shim spacers 94 are ?tted
wardly of the front panel 28. The knob 52 provides
intermediate the X-ray tube housing 10 and the adapter
manual control of transverse dimension of the X-ray
beam, while the knob 52 provides manual control of the
longitudinal dimension. The function of each knob is
82 so that the collimator 20 can be accurately positioned
indicated by adjacent markings on the front panel 28.
axially of the beam.
As thus far described, the swivel ring permits the
5 collimator to be rotated freely about the axis of the
X-ray beam to be delineated. The purpose of this rota
FIG. 1 illustrates a selected S.I.D. of 180 cm. For that
tion is to permit the collimator to be moved from one
particular S.I.D. and a given ?lm size there is a maxi
position to another relative to the X-ray tube to locate
mum permissible shutteropening. The operator can
the front panel and its controls in a desired location for
irradiate the maximum permissible ?eld size or less and
the ?eld size which will be irradiated is displayed by the 20 a given study. Once the collimator has been positioned,
it is desirable to lock it in its adjusted position. The
indicator discs 38, 40.
locking is accomplished by a spring-biaased plunger 96
The collimator 20 also has the capability to automati
which is carried out by the swivel mount 72 and releas
cally select ?eld sizes to properly irradiate standard
ably engages depressions in the swivel ring 76.
X-ray ?lm sizes at selected S.I.D.s. This capability is
The inner end of the plunger 96 carries a ball 97 and
known as “positive beam limitation”, or P.B.L. and the 25
the ball 97, through the plunger 96, is biased by a spring
operability of this feature is indicated on the front panel
28 by an indicator light 56. If the operator tries to create
98 (dotted lines in FIG. 4) into engagement with the
swivel ring 76. A threaded knob 99 controls the dis
a ?eld size larger or smaller than that permitted for a
placement of the plunger 96. By retracting the knob 99,
given S.I.D. and ?lm size, the driver assembly 300 auto
matically functions to drive the vane and shutter assem
the biasing force on the plunger 96 eventually is loos
bly back to maximum permissible ?eld size.
A control button 58 is provided to de-activate one
side of the P.B.L. feature and, when the button 58 is
ened to the point where the ball 97 can move with
respect to the ring 76. Thereafter the collimator can be
rotated to another position. The collimator can be
depressed, the button lights indicating that the system is
locked in place there upon tightening of the knob 99 and
in manually P.B.L. This allows the operator to manu 35 concurrent engagement between the ball 97 and a de
pression in the swivel ring 76.
ally adjust the shutters, longitudinal or transverse, to
III. The Vane and Shutter Assembly
X-ray ?eld sizes smaller than the cassette size but not
The vane and shutter mechanism includes an adjust
larger.
able set of diaphragms which delineate the perimeter of
Certain other collimator functions are controlled or
the X-ray beam 21. The vane and shutter mechanism
indicated by components included as part of the front
includes a main shutter assembly 102 supported in a
panel 28. A pushbutton 60 controls operation of the
centering light assembly 360 and a safety light 62 indi
cates, when lighted, certain conditions like being ouf of
lower portion of the housing 22 as well as a so-called
off-focus vane assembly 104 interposed between the
main shutter assembly 102 and the X-ray tube 12. The
P.B.L. range or ?lter is removed, exist and X-ray expo
sures cannot be made. The collimator functions associ 45 function of both the on-focus and off-focus assemblies is
described fully in the Off-Focus Patent which is incor
ated with the pushbutton 60 and the light 62 will be
described subsequently.
The rear panel 30 includes a fan cover assembly 64.
The fan cover assembly 64 is apertured to permit elec
trical components within the collimator housing 22 to
be cooled. The fan cover assembly 64 also includes an
opening throughlwhich an electrical input 66 extends.
II. The Mounting Assembly 70
porated by reference and further discussion regarding
their basic functions is unnecessary here.
The main shutter assembly 102 includes two nested
pairs of transverse radiation-absorbing shutters 106, 108
and 110, 112 which are moveable toward and away
from one another and the front and rear panels to delin
eate a transverse beam dimension. Another pair of radi
The mounting assembly 70 is secured to the top of the
ation absorbing shutters 114, 116 are supported indepen
housing 22 and surrounds the input end opening 24 as 55 dently of the transverse shutter pairs 106, 108 and 110,
shown best in FIGS. 4 and 5. The mounting assembly 70
112 for movement perpendicular to them to delineate
includes a swivel mount 72 secured to a top plate 73 of
the longitudinal beam limits.
the housing 22 by fasteners 74. A swivel ring 76 is rota
The compactness of the collimator 20 is improved
tively mounted above the top plate 73. The ring 76 has
considerably by a parallelogram linkage mounting of
an outwardly extending ?ange 78 which is between the 60 the transverse shutters. (See FIGS. 5 and 7). This
top plate 73 an inwardly extending annular ?ange 80
mounting permits two sets of nested shutters 106, 108
carried by the swivel mount 72. This construction holds
and 110, 112 to move relatively so that each of the four
the ring 76 and the mount 72 together while permitting
them to be rotated relatively.
An adapter 82 connects the X-ray tube housing 10
and the mounting assembly 70. The adapter 82 has an
outwardly extending annular ?ange 84 which underlies
shutters 106, 108, 110, 112 moves relative to the remain
ing three as beam delineating adjustments are made. As
shown in FIGS. 5 and 7, the shutter 106 is supported by
arms 118, 120 on opposed sides of the collimator. Simi
larly the shutter 108 is supported by arms 122, 124. The
shutter 110 is supported by arms 126, 128 and the shut~
and engages an inwardly extending ?ange 86 on the
4,246,488
7
ter 112 is supported by arms 130, 132. The longitudinal
shutters 114, 116 are each supported by a pair of arms
with one arm of each pair being shown at 136 and 140
respectively in FIG. 6.
a
8
shutters and the vanes 228, 230 are movable with the
longitudinal shutters. As set forth more fully in the
Off-Focus Patent, the vanes are formed by inclined,
generally vertically extending stems to which plate-like
The arms 122, 124, 130, 132 are mounted pivotally to
structures are secured. The plates are spaced along the
chassis side plates 142, 144 by shoulder screws 146, 148,
150, 152. Sector gears 154, 156 are secured, respec
length of the stems and the transverse and longitudinal
plates are interleaved to permit the vane pairs to move
toward and away from each other.
tively, to the arms 124, 132 for interconnected concur
rent movement to provide a driving relationship among
the transverse shutters.
The shutter support arms 118, 120, 126, 128 are rota
In the Off-Focus Patent, the vanes were mounted
pivotally and such a mounting required that the inter
leaved plates be spaced a rather considerable distance as
tively secured to the arms 122, 124, 130, 132, respec
tively, by shoulder rivets 158, 160, 162 164. In turn, the
compared with the present construction, along the stem
arms 118, 120, and 126, 128 are connected to the chassis
during its back and forth movement. The present inven
side plates 142, 144 by links 166, 168, 170, 172. The links
tion permits the interleaved plates to be positioned
166, 168, 170, 172 are rotatively connected to the chassis
side plates by shoulder screws 174, 176, 178, 180 and to
the arms 118, 120, 126, 128 by shoulder rivets 182, 186,
188. Upper links, two of which are shown at 190, 192 in
FIG. 7, are connected to the arms 122, 124, 130, 132 and
to the links 166, 168, 170, 172 in a parallelogram ar
rangement. The upper links 190, 192 include upstanding
drive sections 194, 196 which drive components of the
off ?eld focus shutter assembly 104 when the main shut
closer to each other so that the overall height of the
off-focus vane assembly is reduced.
ters are adjusted.
A segmented drive gear 198 is provided for the trans
verse shutters. The drive gear 198 includes a toothed
portion 200 engageable with the drive assembly 300.
to accommodate the are which each plate traversed
This compact, off-focus vane assembly is provided by
a vane mounting system which supports the vane pairs
224, 226, 228, 230 for reciprocal movement. As in the
Off-Focus Patent, the vanes are connected to the on
focus shutter assembly for concurrent movement so that
the drive system 300 employed to drive the main shutter
assembly 102 also drives the off-focus shutter assembly
25 104.
The mounting system for the transverse vanes 224,
226 includes vane support brackets 232, 234, FIGS. 5
and 7. The vane support brackets 232, 234 are carried by
spaced and parallel guide rods 236, 238 which in turn
The drive gear 198 is pivotally secured to the trans
versely movable shutters by the shoulder screw 148 and 30 are supported there by vertical mounting posts 240, 242,
a bottonhead screw 202 which connects the gear'198 to
the arm 124. When the gear 198 is driven‘ about its rota
tional axis de?ned by the shoulder screw 148, the shut
ters 106, 108, 110, 112 can be moved from their extreme
244, 246. The vane support bracket 232 at one side
includes a pair of spaced, apertured bosses 248, 250
through which the rod 238 extends. The other side of
the vane support bracket 232 is in the form of an aper
_ As seen most clearly in FIG. 7 the mounting member
tured boss 252 which is supported by the rod 236 for
reciprocal movement. The other vane support bracket
234 is constructed similarly and includes spaced bosses
254, 256 which ride upon the rod 236. The other side of
or links for each transverse shutter pair interconnect to
the vane support bracket 234 includes a single boss 258
open position (full line position in FIG. 7) in which each
pair is in a nested relation to their completely closed
position (dotted ‘line position in FIG. 7).
form a parallelogram. One pair 106, 108 is supported at 40 which rides upon the rod 238. A compression spring 260
is carried by the rod 236 and is ?tted between the bosses
one end, for example, by the link 166, and two arms 122,
252 and 254. A spring 262 is carried by the other rod 238
118. As this pair 106, 108 moves four points coincident
and is disposed between the bosses 250 and 258. The
with two shoulder screws 146, 174 and two shoulder
springs 260, 262 urge the bosses and their connected
rivets 158, 182 de?ne such a parallelogram.
The mounting and operation of the longitudinal shut
ters is best shown in FIG. 6. The longitudinal shutters
114, 116 are mounted pivotally to chassis end plate 206
by means of shoulder screws 210, 211 comparable
shoulder screws, not shown, mounted the remote ends
of the shutters. Sector gears 212, 214 are secured to the
arms 136, 140 and mesh with each other in driving
relationship. A drive gear 216 is secured through struc
ture which is not shown to the sector gear 214 to pivot
about the axis of its shoulder screw. A toothed portion
217 of the drive gear 216 is engaged by the drive system
300. When the drive gear 216 is rotated, the longitudi
nally movable shutters 114, 116 will be moved toward
and away from each other.
An off-?eld focus drive bracket 218 is connected to
the arm 136 and pivots with the arm 136 about the
shoulder screw 210. A buttonhead screw 220 adjustably
secures one end of the drive bracket 218 to the arm 136.
The other end of the bracket 218 carries a drive pin 222
which is employed to drive portions of the off-focus
vane assembly 104.
The off-focus vane assembly 104 includes opposed
45 vane pairs away from each other.
Cross connections, not shown, connect the left hand
(as viewed in FIG. 7) drive section 194 to the right hand
vane 226 and the other drive section 196 and the vane
224 together. By this construction the off-focus vanes
are moved from their solid to dotted line positions con
currently with movement of the main shutter between
them solid and dotted line positions. The springs 260,
262 provide an off-focus vane drive system which is free
of backlash and, furthermore, the vanes do not bind
during their movement because the rods 236, 238 are
parallel, the rods are polished, and the springs 260, 232
produce balanced forces.
The mounting system for the longitudinal vanes 228,
230 is similar to that of the transverse vanes 224, 226.
Speci?cally, the vanes 228, 230 are carried by vane
support brackets, one of which is shown at 264 in FIG.
6. The support brackets for the vanes 228, 230 corre
spond to the vane support brackets 232, 234. The longi
tudinal vane support brackets are carried by polished,
65 parallel rods 268, 270 which in turn are supported by
the vertical mounting posts 240, 242, 244, 246. The
pairs of beam-delineating vanes 224, 226 and 228, 230.
parallel rods 268, 270 are spaced vertically from and are
The vanes 224, 226 are movable with the transverse
at right angles with the rods 236, 238. A compression
4,246,488‘
10
spring 272 is carried by the rod 268, and a comparable
spring, not shown, is around the rod 270 to bias the
trols really were manual motor position controls and
not manual shutter controls, as such.
transverse vane support brackets apart, in the same
manner as has been described for the vane support
20 includes a transverse vane control potentiometer
A portion of the control circuitry for the collimator
indicated generally by the arrow 332, FIG. 11. The
potentiometer 332 functions to provide an electrical
signal of a value indicative of the position of the trans
verse shutter assembly. A potentiometer drive spur gear
brackets 232, 234.
The actuating mechanism for the off~focus vane as
sembly includes a link 276 (FIG. 6) secured at one end
to the vane support bracket 264 by a pivotal connection
278. The other end of the link 276 includes a slot 280
within which the pin 222 rides. When the arm 136 is
pivoted counterclockwise as viewed in. FIG. 6, the pin
222 also will be pivoted counterclockwise and the link
334 to turn a potentiometer input shaft whenever the
transverse vanes are adjusted either automatically or
manually.
A longitudinal vane motor assembly 336 (FIG. 17)
drives the longitudinal shutters 114, 116 and the longitu
dinal vanes 228, 230. The longitudinal motor assembly
276 will be advanced to the left. This will urge the vane
support brapket 264 to the left against the spring bias
exerted by the spring 1272. In turn, the vane 230 will be 5 336 includes a gear motor 338. An output bevel gear 340
is ?xed to the output shaft of the motor 338 to drive a
moved toward the vane 228. Concurrently, a link (not
coacting bevel gear 342. The coacting bevel gear 342 is
shown) supported at the other end of the collimator 20
.
acts on the vane 228 to advance it to the right as viewed
in FIG. 6.
‘
IV. The Drive Assembly 300
The drive assembly 300 controls the movement of the
vane and shutter assemblies 102, 104. Referring to
FIGS. 9 and 10 the drive assembly 300 has a drive as
sembly frame 302 which includes tabs 304, 306, 308 for
chassis mounting at locations not shown. The frame 302
also has a tab 310 which is secured to the chassis side
plate 144.
A transverse motor subassembly 312 is carried in an
upper portion as the frame 302, FIG. 10. The motor
subassembly 312 drives the transverse shutters and
vanes. The motor subassembly 312 includes an electric
gear motor 314 positioned laterally of the collimator 20
and mounted behind the back face of the front panel 28.
The output of the gear motor 314 drives a clutch 315, a
motor output spur gear 316, and an intermediate spur
gear 318. The clutch 315 includes curved washers 317
which are under compression to transmit torque from
the gear motor 318 to the output spur gear 316. The
spring compression can be adjusted to permit the spur
secured to a shaft 344 which is journaled for rotation on
the drive assembly frame 302. A slip clutch 346 which is
similar to the clutch 315, is carried by the shaft 344. The
slip clutch 346 includes curved washers 348 which are
under compression to transmit torque from the gearmo
tor 338 via the bevel gears 340, 342 and the shaft 344.
The torque is transmitted by the clutch 346 to a longitu
dinal shutter drive spur gear 350 that is concentrically
mounted on a drive collar 352 threaded on the shaft 344.
The threading of the collar 352 on the shaft 334 permits
the clutch spring compression to be adjusted for slip
page when torque in excess of a predetermined maxi
mum is attained.
A longitudinal vane ?eld size, control shaft 354 is
journaled in the frame 302, FIG. 10. A ?eld size control
spur gear 356 is mounted on the ?eld size shaft 354 and
in driving relationship with the shutter drive spur gear
350. The ?eld size indicator disc 40 is mounted on an
end of the ?eld size shaft 354 remote from the ?eld size
spur gear 356. The ?eld size control spur gear 356 is in
driving engagement with toothed portion 217 of the
longitudinal shutter drive gear 216. Accordingly, motor
driven longitudinal vane adjustment is achieved
through the longitudinal slip clutch 346 and the spur
gear 316 to slip relative to the gear motor 314 when
about 5.0 inch pounds of torque are attained.
gears 350, 356.
The intermediate spur gear 318 is connected by a
A manual longitudinal shutter drive spur gear, identi
drive shaft 319 to collimator drive spur gear 320 posi
cal to the spur gear 324, is secured to the longitudinal
tioned outside the bracket 302. The drive spur gear 320 45 shutter control knob 54 and connected with the ?eld
meshes with the toothed portion 200 of the segmental
size indicator disc 40.- Accordingly, rotation of the lon
drive gear 198 to effect adjustment of the transverse
gitudinal ?eld size knob 54 drives the disc 40 through
collimator vanes.
the gear, not shown, and the disc 40 in turn drives the
The transverse shutter assembly also can be con
?eld size control spur gear 356 to effect manual longitu
trolled manually. The knob 52 is carried by a shaft 322
dinal shutter adjustment.
which also carries a manual drive spur gear 324. The
The frame 302 also supports an S.I.D. drive shaft 357,
manual drive gear 324 is in driving relationship with the
FIG. 11. An S.I.D. spur gear 358 is secured to the shaft
?eld size indicator disc 38. The disc 38 is supported by
357 between the frame 302 and the front panel 28. The
a shaft 326. A bevel gear 328 is ?xed to the shaft 326 and
S.I.D. shaft 357 extends through the front panel 28 and
meshes with another bevel gear 338 carried by the drive
the S.I.D. selector knob 50 is attached to it. The win
shaft 319. When the transverse motor subassembly 312
dowed S.I.D. selector discs 42, 44 each are rotatively
is energized to control the position of the transverse
driven by the S.I.D. spur gear 358. Accordingly, upon
vanes and shutters, the ?eld size indicator disc 38 will be
rotation of the knob 50, the S.I.D spur gear 358 and,
driven through the bevel gearing to indicate to the
hence, the S.I.D. selector discs 42, 44 are rotated. An
operator the position of the shutters and vanes. On the 60 S.I.D. spring-biased detent mechanism 359 (FIG. 10)
other hand, if power to the collimator should fail, or if
engages the gear 358 to index the S.I.D. selector discs
the operator wishes to select the ?eld size manually,
42, 44.
rotation of the knob 52 will, through the bevel gearing
V. The Centering Light Assembly 360
and the spur gear'320, produce the desired movement in
The centering light assembly 360 performs two basic
the transverse shutters. An advantage of the foregoing 65 functions: it provides a visual indication of the area of
gearing arrangement is that the shutter assembly can be
the X-ray beam 21 and it provides a thin fan shape
driven manually without rotating the motor because the
centering light beam to enable the collimator to be
clutch 315 readily will slip. Prior manual shutter con
centered on the center of an X-ray ?lm-carrying tray.
4,246,488
11
The centering light arrangement is an improvement
12
provide a space into which portions of the other plates
over, but is used in the same manner as, the light de
can extend. The ?ange and lip 454 also acts as a ?nger
scribed in the Centering Patent. Referring to FIGS. 5
grip by which the ?lter assembly 442 can be moved into
or out of position within the receptacle 449.
The supplemental plates 444, 446 and 448 each have a
pair of spaced end tabs respectively designated as 456,
458 and 462, 464 and 468, 470. The supplemental plates
and 8, the centering light assembly 360 includes a light
source sub assembly 362 and a pair of light beam mir
rors 364, 366. A cylindrical lens 368 is provided to focus
the light beam and a membrane mirror 370 is provided
for beam size indication.
' v
The bottom window 36 includes the crosshairs 37
which are conventional and are located at right angles.
The window 36 is secured in place within the housing
22 by clamps 378, 380 which are secured to the housing
22 by fasteners 382.
The light source sub assembly 362 includes a housing
respectively have rectangular apertures 460, 466, 472.
Each plate may be inserted, apertured end ?rst, so that
when its aperture is aligned with the X-ray beam it has
no ?ltration effect. Alternately each plate may be in
serted apertured end last to provide a ?ltration effect.
Thus the supplemental ?lters are always maintained
within the collimator but the desired ?ltration effect
384 secured to the rear panel 30 by a bracket 386. A
may be selected by appropriately positioning the sup
lamp 387 is disposed within the housing 384. A motor
plemental ?lter plates.
driven cooling fan 388 is disposed near the housing 362.
The supplemental ?lter plate end tabs are laterally
The fan 388 is mounted within apertured fan cover
staggered so that the end,tab at the innermost end will
assembly 64 behind the rear panel 30.
overlie the rear edge of the main ?lter plate 442 and its
The housing 362 includes a fan beam light opening 20 forward tab will ?t in a slot de?ned by the ?lter locating
390 in its upper surface. The fan beam opening 390
end wall 450 and the ?ange and lip 454.
together with apertured beam delineating plates 391 and
When viewed from the end ,(FIG. 13) the receptacle
the lens 368 produce a thin beam of light 392. The beam
449 is a channel-like member having upturned, inwardly
392 is projected onto the ?rst light beam mirror 364,
facing side channels 476, 478 within which the tabs of
re?ected to the second light beam mirror 366 which 25 the ?lter plates are received. The receptacle 449 in
re?ects the beam through the lens 368. This beam of
cludes a bottom plate 480 having a rectangular opening
light 392 is projected onto an X-ray ?lm-carrying tray
to enable the collimator and the tray to be relatively
positioned.
The housing 362 has a second light opening 394
through which an X-ray simulating beam of light 396
projects. The simulating light beam 396 re?ects off the
membrane mirror and then through the window 36.
The lamp 387 is positioned such that its ?lament is
spaced from the mirror a distance equal to the spacing
of the X-ray tube focal spot 16 from the mirror. With
this arrangement the length of the path of the simulating
beam 396 is identical to the length of the path of X-ray
482, FIG. 12, slightly larger than the supplemental ?lter
plate apertures 460, 466, 472. The opening 482 is aligned
with the X-ray beam 21 so that if no ?lter plates are
present, no attenuation of the X-ray beam will occur.
A pair of spaced detent pins 484, 486 are provided to
retain the stacked ?lter plates‘ in place and properly
aligned with the opening 482. The detent pins 484, 486
are rounded at their upper ends and are secured at their
lower ends to ?exible spring ?ngers 488,490. The open
ing ?ngers 488, 490 are secured to the underside of the
bottom plate 480 by fasteners 492. The underside of the
main plate 442 is provided with indentations into which
the detent pins 482, 486 are urged when the ?lter is
beam 21 when radiographic studies are being con
ducted.
40 properly inserted completely into the receptacle 449.
As an operator is setting up for a given diagnostic
A limit switch 494 is attached to the bottom plate 480
procedure, adjustment of the collimator shutters deline
at a location remote from the opening in the side panel
ates the longitudinal and transverse dimensions of the
32, FIG. 12. The limit switch includes a contact arm 496
simulating beam 396. Accordingly, the beam 396 illumi
which is engaged by the end of the plate 442 when the ‘
nates a portion of the patient corresponding exactly to 45 plate 442 is inserted completely into the receptacle 449.
that portion of the patient which will be struck by the
The limit switch 494 performs a control function which
X-ray beam 21 when the radiograph is made.
is that when the ?lter is removed, the contact arm 496 is
VI. The Filter Assembly 440
moved enough to trip the limit switch. An electrical
The ?lter assembly 440 is accessible from the right
signal is generated which prevents generation of X-rays
hand side of the collimator as viewed in FIG. 1. It is 50 at a tub voltage potential of over 50 kilowats. When the
positioned in the collimator 20 at a location intermedi
plate 442 is in place within the receptacle 449 the switch
ate the off-focus vane assembly 104 and the main shutter
494 will be tripped and operation of the X-ray tube 12 at
assembly 102. To facilitate access, the ?lter assembly
voltage levels over 50 kv. is possible.
440 is a drawer-like mechanism which is removable
VII. The Control System 500
from the collimator 20 through an opening in the side 55
FIG. 15 illustrates one control system 500 which can
panel 32.
conveniently be utilized to automatically control opera
tion of the improved collimator. The system 500 in
main and supplemental aluminum ?lter plates 442, 444,
cludes a number of inputs both digital and analog which
446, 448 (FIG. 14) which may be ?tted together in
control operation of a micro-processor 520. Depending
different combinations to provide a desired ?ltering 60 on the state of these various inputs, signals to the micro
capacity. The assembly 440 also includes a ?lter plate
processor help condition a driver 570 which in turn
receptacle 449 which receives the stacked plates in
controls driving motors 312, 336 within‘the drive as
The ?lter assembly 440 includes a plurality of stacked
sliding relationship.
.
sembly 300.
The main ?lter plate 442 includes a downwardly
The improved collimator may be utilized in a number
turned ?ange and lip 454 at its outer end, A ?lter assem 65 of conditions under other than a typical embodiment
bly locating end wall 450 having an aperture 451 is
where the collimator is in a vertical position placed
secured by fasteners 452 to the ?ange and lip 454. Spac
above a table which supports the patient. A number of
ers 453 are ?tted between the ?ange and the end wall to
digital inputs 532a-n indicate to the micro-processor
13
4,246,488
14
520 which of these conditions the collimator is posi
‘ phragms to a position where the exposure ?eld is less
tioned. The digital inputs might, for example, indicate
1 than the optimum size for the particular SID in use, he
I can manually override the control signals causing the
the X-ray ?lm was mounted on a wall with the X-ray
propagation in a horizontal direction and the collimator
clutch mechanism within the control assembly 300 to
slip. When this is done the ?eld of the exposure can be
reduced and although the micro-processor sends con»
positioned parallel to the floor. For illustration pur
poses, it will be assumed that the collimator is posi
tioned in a vertical orientation and the X-ray source
trol signals to change the smaller ?eld size, these signals
sends X-rays to a table Bucky tray supported X-ray
are overriden by the user’s manual control due to slip
?lm. This orientation will be characterized by a unique
con?guration of digital inputs to a data selector 530
within the control system 500.
In order to operate in the so called positive beam
limitation mode, it is necessary for the micro-processor
to receive information concerning the source to image
distance. The SID is one of the analog inputs to the 5
control system 500. The SID can be changed to one of
four different conventional values and this distance is
represented by an analog input which varies as the SID
changes.
page in the clutch mechanism. When the user releases
this manual override, the micro-processor again regains
control of the system apertures causing the ?eld size to
automatically return to its optimum calculated size.
What is claimed is:
1. An X-radiation collimator including a frame and
having a beam axis comprising:
(a) a plurality of pivotally mounted shutters arranged
in paired relationship to delineate the perimeter of
an X-ray beam of generally rectangular cross-sec
tional con?guration;
(b) certain pairs of said shutter members being posi
As the SID changes, the proper diaphragm opening
also changes. This proper diaphragm opening is a func
tion of the SID distance and the control system 500
includes a method for comparison of the actual ?eld size
as de?ned by the diaphragm openings with an optimum
?eld size as calculated by the microprocessor. In order 25
to calculate this optimum ?eld size, the micro-processor
must be instructed as to which SID is being utilized.
tioned to delineate two parallel and spaced sides of
the beam;
(c) the shutters of each of said certain pairs being
connected together by a plurality of links;
(d) the links being pivotally interconnected in a paral—
lelogram relationship and being pivotally mounted
on the collimator frame; and
(e) each of the shutters of said certain pair having an
Therefore, the analog SID input to the control system is
necessary for micro-processor functioning and control.
The proper ?eld size calculation takes place in a mi
cro-processor, but is controlled by the operation of two
memory units 550, 560. One unit 550 is dedicated read
only memory which contains a preprogrammed algo
rithm instructing the processor what steps to perform.
The second memory unit 560 is programmed by the user 35
open position wherein one of the shutters is in a
nested relationship above the other when the axis is
vertical to delineate a full open position and each
shutter .of said certain pairs having a full closed
position wherein a ?rst of the shutters of each cer
tain pair is in touching relationship with the other
?rst shutter and the remaining shutters of the cer
and instructs the micro-processor what ?eld sizes are
tain pairs are outward relative to the ?rst shutters
appropriate for a given SID. The ram or random access
and each remaining shutter is in overlapping rela
tionship with its ?rst shutter whereby to fully block
the exit of an X-ray beam from the collimator.
memory unit 560 is programmed through an input/out
put expander 540. As programmed by the user, the ram
memory unit is capable of calculating the proper ?eld
2. The collimator of claim 1 wherein a drive gear
dimensions for a given SID and does so in response to
train is coupled to the pairs of shutters and wherein both
instructions from the central processing unit or the
micro-processor 520. Once the proper ?eld dimensions
a manual control and a motor are connected to the gear
train and wherein the gear train includes a slip clutch.
3. In a radiographic X-ray collimator an off-focus
have been calculated they are sent to a converter and
multi-plexer unit 510.
As the micro-processor is sending output signals in
dicative of the optimum ?eld size the potentiometer
45
units in the transverse and longitudinal drive assemblies
are sending analog inputs to the control system 500
indicative of the actual ?eld size as de?ned by the colli
mator shutter settings. This analog information is con
verted to digital signals in a converter and compared to
the control signals generated by the micro-processor
520. The comparison between actual and optimum ?eld
size results in an output from the converter and multi 55
plexer 510 which instructs the micro-processor whether
a discrepancy exists between optimum and actual ?eld
sizes. If there is a difference between these two values,
output 512 results in a micro-processor output to the
driver 570 instructing that driver to power the collima
tor motors 312, 336 in a direction which will narrow the
discrepancy between actual and optimum ?eld size. If
the ?eld size is already at the optimum or nearly at that
level, no driver signal is generated and the collimator
diaphragm opening is maintained at a constant level.
65
vane assembly comprising:
(a) orthogonally oriented pairs of guide tracks posi
tioned generally symmetrically about an axis of the
collimator and of the X-ray beam to be delineated;
(b) two pairs of off-focus vanes with one pair of vanes
being reciprocally mounted on one pair of guide
tracks and the other pair of vanes reciprocally
mounted on the other pair of guide tracks;
(c) the vanes including a plurality of inter?tting arms
disposed laterally of any plane located by the axis
of an X-ray beam to be delineated; and
(d) an on focus shutter assembly and linkage means
interconnecting the on focus shutter assembly and
the off focus vanes whereby adjustment of the
shutter assembly will cause concurrent and coordi~
nated off ?eld vane adjustment.
4. For use in a radiographic collimator, a ?lter assem
bly comprising:
(a) a main ?lter of generally rectangular con?gura
tion;
(b) a plurality of supplemental ?lters each of an over
ually override these control signals as generated by the
all con?guration corresponding to that of the main
?lter and each including a through aperture and a
micro-processor. If the user wishes to drive the dia
?ltering portion; and
The present collimator design allows the user to man
15
4,246,488
(0) each of the supplemental ?lters being adapted to
16
(b) diaphragm means for delineating the beam to a
be positioned with either its aperture aligned with '- a ‘
?eld;
(c) centering means including a light source for send
ing a visible light signal to a portion of the ?eld
thereby enabling a user to position the non-visible
the ?ltering portion of the main ?lter such that it is
in a non?ltering stored orientation, or with its ?l
tering portion aligned with the ?ltering portions
X-radiation;
for the main ?lter to provide ?ltration additive to
that of the main ?lter.
5. The ?ltering arrangement of claim 4 wherein each
of the supplemental ?lters has end locating tabs for
overlying the ends of the main ?lter and wherein the
((1) said centering means including a partially re?ec
tive mirror positioned within the beam for receiv
ing visible light from a source and for re?ecting it
to the plane of X-ray exposure; and
tabs of one supplemental ?lter are transversely offset
(e) ?eld illuminating means including said light
source for illuminating an X-ray beam stimulating
?eld.
11. A radiographic collimator including a frame and
having a beam axis comprising:
(a) a plurality of pivotally mounted shutters arranged
from the tabs of each other supplemental ?lter.
6. The device of claim 5 wherein an end plate is se
- cured to the main ?lter at least partially in spaced rela
tionship to provide a space to receive one of the tabs of
each of the supplemental ?lters.
7. A radiation collimator comprising:
in paired relationship to delineate the perimeter of
an X-ray beam of generally rectangular cross-sec
(a) an X-ray source for emitting a beam of X-radia
tion;
(b) diaphragm means for delineating an on focus 20
tioned to delineate two parallel and spaced sides of
beam;
(0) off-focus collimator means connected to said dia
phragm means for co-ordinate movement, said
means including opposed portions con?ned sub
stantially to a plane intermediate the source and
diaphragm means and moveable relative to each
25
(d) drive means for moving said opposed portions in
said plane.
30
tion;
(b) diaphragms for delineating the beam;
-
the beam;
(c) the shutters of each of said certain pairs being
connected together by a plurality of links;
(d) the links being pivotally interconnected in a paral
lelogram relationship and being pivotally mounted
other to block off-focus radiation; and
8. A radiation collimator comprising:
(a) an X-ray source for emitting a beam of X-radia
tional con?guration;
(b) certain pairs of said shutter members being posi
on the collimator frame;
(e) each of the shutters of said certain pairs having an
open position wherein one of the shutters is in a
nested relationship above the other when the axis is
vertical to delineate a full open position and each
shutter of said certain parts having a full closed
position wherein a ?rst of the shutters of each cer
(c) drive means coupled to the diaphragms to provide -
tain pair is in touching relationship with the other
movement to said diaphragms and including a
?rst shutter and the remaining shutters of the cer
tain pair are outward relative to the ?rst shutters
clutch;
(d) adjustment means coupled to the drive means for
manually adjusting the diaphragm position by caus
ing the clutch to slip thereby adjusting the beam
delineation; and
(e) automatic means for positioning of the diaphragms
if said diaphragms have been manually positioned
to delineate a beam too large for existing condi
tions.
45
9. A radiation collimator comprising:
(a) an X-ray source for emitting a beam of radiation;
(b) diaphragms for delineating the beam; said dia
and each remaining shutter is in overlapping rela
tionship with its ?rst shutter whereby to fully block
the exit of an X-ray beam from the collimator;
(f) orthogonally oriented pairs of guide tracks posi
tioned generally symmetrically about an axis of the
collimator and of the X-ray beam to be delineated;
(g) two pairs of off-focus vanes with one pair of vanes
being reciprocably mounted on the pair of guide
tracks and the other pair of vanes reciprocally
mounted on the other pair of guide tracks;
(h) the vanes including a plurality of inter?tting arms
phragms including a ?rst and second radiation
disposed laterally of any plane located by the axis
absorption structures;
of an X-ray beam to be delineated; and
(0) drive means including a gear mounted for rota
tional movement;
(d) a mount; and
(e) linkage structure connected to said diaphragms;
(i) a linkage interconnecting the shutters and the off
focus vanes whereby adjustment of the shutters
will cause concurrent and coordinated off ?eld
vane adjustment.
12. The radiographic collimator of claim 11 wherein
and drive means and said mount for transmitting 55
a ?lter assembly is provided and positionable between
motion from the rotating drive means to the dia
phragm; said linkage including;
(i) a ?rst arm attached to the ?rst absorption struc
ture and to the mount;
(ii) a second arm attached to the second absorption 60
structure and to the mount; and
(iii) ?rst and second gear means connected to said
?rst and second arms respectively and meshing
with each other to coordinate movement of said
?rst and second arms.
65
10. A radiation collimator comprising:
(a) an X-ray source for emitting a beam of X-radia
tion;
the vanes and shutters, the ?lter assembly comprising:
(a) a main ?lter of generally rectangular con?gura
tion;
(b) a plurality of supplemental ?lters each of an over
all con?guration corresponding to that of the main
?lter and each including a through aperture and a
?ltering portion; and
(0) each of the supplemental ?lters being adapted to
be positioned with either its aperture aligned with
the ?ltering portion of the main ?lter such that it is
in a non?ltering stored orientation, or with its ?l
tering portion aligned with the ?ltering portions
17
4,246,488
18
(b) certain pairs of said shutter members being posi
for the main ?lter to provide ?ltration additive to
that of the main ?lter.
tioned to delineate two parallel and spaced sides of the
beam;
13. The radiographic collimator of claim 12 further
-
(c) the shutters of each of said certain pairs being
connected together by a» plurality of links;
(d) the links being pivotally interconnected in a paral
including a centering means including a light source for
sending a visible light signal to a portion of the ?eld
thereby enabling a user to position the non-visible X
lelogram relationship and being pivotally mounted
radiation; said centering means including a partially
re?ective mirror positioned within the beam for receiv
on the collimator frame; and
(e) each of the shutters of said certain pairs having an
ing visible light from a source and for re?ecting it to the 0
open position wherein one of the shutters is in a
plane of X-ray exposure; and ?eld illuminating means
including said light source for illuminating an X-ray
beam simulating ?eld.
14. The radiographic collimator of claim 11 wherein
there is an adjustment means for manually adjusting the
shutter and vane positions and thereby adjusting the
nested relationship above the other when the axis is
outward relative to the ?rst shutters and each re
beam delineation; and an automatic means is provided
overriding said manual means to control positioning of
its ?rst shutter whereby to fully block the exit of an
the shutters whenever the shutters have been manually
X-ray beam from the collimator; and another of
vertical to delineate a full open position and shut
ters of the certain pairs having a full closed position
wherein a ?rst of the shutters of each certain pair is
in touching relationship with the other ?rst shutter
and the remaining shutters of the certain pairs are
maining shutter is in overlapping relationship with
said shutter pairs being pivotally mounted within
positioned to delineate a beam too large for existent
paths
through which the interconnected certain
conditions.
shutter pairs move in their adjustment range.
15. An X-radiation collimator including a frame and
16. The collimator of claim 15 wherein a pair of drive
having a beam axis comprising:
25 gear trains are coupled to the pairs of shutters and
(a) a plurality of pivotally mounted shutters arranged
in paired relationship to delineate the perimeter of
wherein both a manual control and a motor are con
nected to each gear train and wherein each gear train
includes a slip clutch.
an X-ray beam of generally rectangular cross-sec
tional con?guration;
=1‘
30
40
45
55
65
*5‘
it
*
1R
UNITED STATES PATENT AND TRADEMARK OFFICE
CERTIFICATE OF CORRECTION
.
PATENT NO.
1
4,246,488
DATED
I
January 20, 1981
INVENTOR(S) 3
Michael Hura
It is certified that error appears in the above-identified patent and that said Letters Patent
are hereby corrected as shown below:
.
.
‘
Col. 1, line 16, change "collmator" to --Collimator"
Col. 1, line 51, after "film." new paragraph should be started”
Col.
Col.
Col.
Col.
2,
2,
3,
3,
line
line
line
line
42, after "arrangement." delete "A".
62, change "fails" to -—fail7, change "adapted" to -—adopted——
46, after "housing" change "with" to —-and—
Col. 3, line 51, change "the" to —-a —
'
‘
Col.
Col.
Col.
Col.
Col.
Col.
Col.
Col.
Col.
Col.
Col.
Col.
5, line 8, after "panel" insert —-285, line 13, change "52" to --546, line 22, change "biaased" to -—biased-—
6, line 23, omit the word "out"
6, line 64, after 'tnade." new paragraph should be started.“
7, line 13, insert "," between 162 and 164
7, line 31, change "bottonhead" to --buttonhead8, line 52, change "them" to --the—
11, line 65, change "end," to --end.15, line 55, change "and" (first occurrence) to --—said~—
16, line 12, change "stimulating" to —-simulating——
16, line 36, change "pair" to —-pairs-—.
Signed and Scaled this
‘
Twenry~ninrh D a y Of T September I98!
[SEAL]
Amsr:
GERALD J‘ MOSSINGHOFF
Arresting Officer
_ Commissioner of Parents and Trademarks

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