(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2006/0198492 A1
`Noguchi
`(43) Pub. Date:
`Sep. 7, 2006
`
`US 2006O198492A1
`
`(54) RADIATION DIAPHRAGM APPARATUS AND
`RADIOTHERAPY APPARATUS HAVING THE
`DAPHRAGMAPPARATUS
`
`(76) Inventor: Tadashi Noguchi, Otawara-shi (JP)
`
`Correspondence Address:
`OBLON, SPIVAK, MCCLELLAND, MAIER &
`NEUSTADT, P.C.
`194O DUKE STREET
`ALEXANDRIA, VA 22314 (US)
`
`(21) Appl. No.:
`
`11/365,519
`
`(22) Filed:
`(30)
`
`Mar. 2, 2006
`Foreign Application Priority Data
`
`Mar. 4, 2005 (JP)...................................... 2005-061599
`Jan. 31, 2006 (JP)...................................... 2006-023577
`
`Publication Classification
`
`(51) Int. Cl.
`(2006.01)
`A6IB 6/00
`(2006.01)
`GOIN 23/00
`(2006.01)
`G2I
`L/12
`(2006.01)
`H05G L/60
`(52) U.S. Cl. ................................................................ 378/15
`
`ABSTRACT
`(57)
`A radiation diaphragm apparatus, which is adapted to form
`a radiation field which is an exposed area of an object to be
`examined to radiation from a radiation source, comprises a
`plurality of diaphragm elements which are closely arranged
`in a first direction and movable along a second direction
`substantially normal to the first direction and each of which
`has a hole of a given shape formed to penetrate through it in
`the first direction, a shaft penetrating through the hole of
`each of the diaphragm elements, and a wear-resistant Surface
`member coating the shaft. The shaft supports each of the
`diaphragm elements at a point of contact with the periphery
`of the hole. The diaphragm elements moves along the
`second direction with support by the shaft.
`
`
`
`10
`
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`Page 1 of 19
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`Patent Application Publication Sep. 7, 2006 Sheet 1 of 12
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`US 2006/0198492 A1
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`Patent Application Publication Sep. 7, 2006 Sheet 3 of 12
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`US 2006/0198492 A1
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`ViewRay Exhibit 1021
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`Patent Application Publication Sep. 7, 2006 Sheet 4 of 12
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`US 2006/0198492 A1
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`Page 5 of 19
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`Patent Application Publication
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`Sep. 7, 2006 Sheet 5 of 12
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`US 2006/0198492 A1
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`Patent Application Publication Sep. 7, 2006 Sheet 6 of 12
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`US 2006/O198492 A1
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`Page 7 of 19
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`Patent Application Publication Sep. 7, 2006 Sheet 7 of 12
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`US 2006/0198492 A1
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`
`
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`(141B)
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`(144B)
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`
`ViewRay Exhibit 1021
`Page 8 of 19
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`Patent Application Publication Sep. 7, 2006 Sheet 8 of 12
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`US 2006/0198492 A1
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`Page 9 of 19
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`Patent Application Publication Sep. 7, 2006 Sheet 9 of 12
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`Patent Application Publication Sep. 7, 2006 Sheet 10 of 12
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`US 2006/O198492 A1
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`ViewRay Exhibit 1021
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`Patent Application Publication Sep. 7, 2006 Sheet 11 of 12
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`US 2006/0198492 A1
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`146A1 (146B1)
`146A2 (146B2)
`146A3(146B3)
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`144A
`(144B)
`
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`ViewRay Exhibit 1021
`Page 12 of 19
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`Patent Application Publication Sep. 7, 2006 Sheet 12 of 12
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`US 2006/O198492 A1
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`Page 13 of 19
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`

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`US 2006/O 198492 A1
`
`Sep. 7, 2006
`
`RADATION DAPHRAGMAPPARATUS AND
`RADIOTHERAPY APPARATUS HAVING THE
`DAPHRAGMAPPARATUS
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`0001. This application is based upon and claims the
`benefit of priority from prior Japanese Patent Applications
`No. 2005-061599, filed Mar. 4, 2005; and No. 2006-023577,
`filed Jan. 31, 2006, the entire contents of both of which are
`incorporated herein by reference.
`
`BACKGROUND OF THE INVENTION
`0002) 1. Field of the Invention
`0003. The present invention relates to a radiation dia
`phragm (stop) apparatus for accurately forming a radiation
`field which is an area to be exposed to radiation for use in
`apparatus adapted for radiotherapy or radiation-based non
`destructive inspection and a radiotherapy apparatus
`equipped with the radiation diaphragm apparatus.
`0004 2. Description of the Related Art
`0005 The radiotherapy apparatus is one which irradiates
`a given region containing a diseased part with ionizing
`radiation to destroy diseased tissues, thereby allowing treat
`ment of the diseased part. Treatments using this apparatus
`include postoperation treatment, under-operation treatment,
`noninvasive treatment, etc. The postoperation treatment is
`to, after a Surgical operation has been performed on a patient
`to remove a malignant tumor in a diseased part, externally
`apply radiation to the diseased part to destroy the remaining
`tumor cells the operation has failed to remove. The under
`operation treatment is to directly apply radiation to unre
`moved tumor cells while the diseased part is cut open. The
`noninvasive treatment is to apply radiation to a diseased part
`of a patient without opening the diseased part. Advances in
`computer technology and medical technology have allowed
`the recent radiotherapy apparatus to irradiate an object of
`treatment with radiation in large doses but irradiate Sur
`rounding normal tissues with as little radiation as possible.
`Thus, the radiotherapy is receiving attention as a treatment
`which has few side effects and is little invasive (or nonin
`vasive).
`0006 With such a radiotherapy apparatus, because of its
`property of irradiating a diseased part with radiation, pro
`visions are made for reducing exposure of a patient to
`radiation. One of the provisions is to equip the apparatus
`with a split diaphragm apparatus for restricting the radiation
`field so that radiation is accurately applied to the diseased
`part (region for treatment) (see, for example, Japanese
`Unexamined Patent Publications Nos. 2004-275.243 and
`2002-210026).
`0007 FIG. 1 is a diagram for use in explanation of an
`example of a conventional split diaphragm apparatus. As
`shown, first diaphragm elements 100A and second dia
`phragm 100B are arranged along one direction (X-axis
`direction in the diagram). The first and second diaphragm
`elements are configured to be movable in the Y-axis direc
`tion normal to the X-axis direction (that is, the first and
`second diaphragm elements facing each other can be moved
`to approach each other or separate from each other). By
`
`moving each diaphragm element to a desired position, a
`radiation field of a desired shape can be formed.
`0008 Each diaphragm element is formed of a heavy
`metal. Such as tungsten, which is capable of blocking
`radiation. Therefore, its weight is heavy and the Supporting
`mechanism requires accommodations. The conventional
`Supporting mechanisms include one which Supports each
`diaphragm block with a grooved roller (see, for example,
`Japanese Unexamined Patent Publication No. 6-2 10012 and
`Japanese Patent Application No. 63-267324), one in which
`each diaphragm element is formed with grooves of V
`(U)-shaped cross section on both sides, balls and retainers
`are placed in the grooves, and springs are placed at both ends
`of each of the grooves to thereby allow adjacent diaphragm
`blocks to Support each other (see, for example, Japanese
`Unexamined Patent Publication No. 2001-066397), etc.
`0009. However, with the conventional radiotherapy appa
`ratus, there are the following problems.
`0010 First, with the method of supporting each dia
`phragm element with a grooved roller, rolling contact results
`in the radial direction while slide friction results in the thrust
`direction. As the result, there arises a possibility that reliable
`accuracy may drop with time due to abrasion. In addition,
`since the diaphragm block is made of a heavy metal Such as
`tungsten, the grooved roller must be increased in diameter.
`Thus, the diaphragm apparatus will increase in size to
`project in the direction of a patient, which will intensify the
`patient’s oppressive feeling. Moreover, it becomes difficult
`to secure space Sufficient to accommodate a standard aux
`iliary apparatus, Such as a block tray, between the radiation
`source and the patient as needed. Furthermore, when the
`diaphragm block is Subdivided, three or more grooved
`rollers must be placed for each diaphragm block. Therefore,
`a large number of rollers must be placed, taking up much
`space. Further, assembly and adjustment also become diffi
`cult.
`0011. With the method of using grooves of V (U)-shaped
`cross section formed on both the sides of each diaphragm
`element, the structure requires a large number of parts and
`a large number of steps of assembly. Thus, the cost
`increases. In addition, because of rolling contact, the driving
`power is low and looseness is liable to occur.
`
`BRIEF SUMMARY OF THE INVENTION
`0012. It is therefore an object of the present invention to
`provide a diaphragm apparatus which Supports diaphragm
`elements Smoothly and reliably and is Small in size, highly
`reliable, and relatively inexpensive and a radiotherapy appa
`ratus using the diaphragm apparatus.
`0013. According to an aspect of the present invention,
`there is provided a radiation diaphragm apparatus which is
`placed between a radiation source and an object to be
`examined and adapted to form a radiation field which is an
`exposed area of the object to be examined to radiation from
`the radiation Source and which comprises: a plurality of
`diaphragm elements which are arranged in a first direction
`and movable along a second direction different from the first
`direction and each of which includes a hole of a predeter
`mined shape formed to penetrate through it in the first
`direction; a Support unit which includes a shaft penetrating
`through the hole of each of the diaphragm elements and a
`
`ViewRay Exhibit 1021
`Page 14 of 19
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`US 2006/O 198492 A1
`
`Sep. 7, 2006
`
`wear-resistant Surface member coating the shaft and Sup
`ports each of the diaphragm elements at a point of contact
`with the periphery of the hole; and a moving unit which
`moves each of the diaphragm elements along the second
`direction to form the radiation field.
`0014. According to another aspect of the present inven
`tion, there is provided a radiotherapy apparatus which com
`prises: a radiation source to irradiate an object to be exam
`ined with radiation; a radiation diaphragm unit placed
`between the radiation source and an object to be examined
`and adapted to form a radiation field which is an exposed
`area of the object to be examined to radiation from the
`radiation Source, which comprises a plurality of diaphragm
`elements which are arranged in a first direction and movable
`along a second direction different from the first direction and
`each of which includes a hole of a predetermined shape
`formed to penetrate through it in the first direction, and a
`Support unit which includes a shaft penetrating through the
`hole of each of the diaphragm elements and a wear-resistant
`Surface member coating the shaft and Supports each of the
`diaphragm elements at a point of contact with the periphery
`of the hole; a moving unit which moves each of the
`diaphragm elements along the second direction to form the
`radiation field; and a control unit which controls the moving
`unit.
`
`BRIEF DESCRIPTION OF THE SEVERAL
`VIEWS OF THE DRAWING
`FIG. 1A is a diagram for use in explanation of an
`0.015
`example of a conventional split diaphragm apparatus;
`0016 FIG. 1B is a schematic exterior view of a radio
`therapy apparatus to which the present invention is applied;
`0017 FIG. 2 is a side view of a diaphragm unit according
`to a first embodiment of the present invention;
`0018 FIG. 3 is another side view of the diaphragm unit
`in a direction substantially normal to FIG. 2;
`0.019
`FIG. 4 is a view of the second diaphragm elements
`141Ak and 141Bk and the second drive units 143Ak and
`143Bk seen from the side of the radiation source S.
`0020 FIG. 5 shows an example of a radiation field U of
`an irregular shape made to approximate the shape of a body
`region to be treated;
`0021
`FIG. 6 is a diagram for use in explanation of a
`mechanism for Supporting second diaphragm elements of
`the diaphragm unit of the embodiment;
`0022 FIG. 7A is a diagram for use in explanation of the
`shape of an elongated hole formed in the second diaphragm
`element shaped into a circular arc:
`0023 FIG. 7B is a diagram for use in explanation of the
`shape of an elongated hole formed in the second diaphragm
`element shaped into a rectangle;
`0024 FIGS. 8A and 8B are diagrams for use in expla
`nation of the forms of portions where the second diaphragm
`element is fitted into peripheral Supporting members;
`0.025
`FIG. 9 is a diagram for use in explanation of an
`example of a diaphragm unit when the diaphragm elements
`are subdivided;
`
`0026 FIG. 10 is a diagram for use in explanation of
`another example of a diaphragm unit when the diaphragm
`elements are subdivided;
`0027 FIG. 11 is a diagram when the diaphragm unit is
`viewed from the radiation irradiation surface toward the
`radiation irradiation apparatus;
`0028)
`FIG. 12 is a side view of the structure shown in
`FIG. 11;
`0029 FIG. 13 is a diagram for use in explanation of a
`Surface member and a shaft in the diaphragm unit of a
`second embodiment of the present invention; and
`0030 FIG. 14 shows another configuration of the surface
`member and the shaft in the diaphragm unit of the second
`embodiment.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`0031. The preferred embodiments of the present inven
`tion will be described hereinafter with reference to the
`accompanying drawings. In the description, the same or
`functionally equivalent elements are denoted by the same or
`similar reference numerals, to thereby simplify the descrip
`tion.
`0032 FIG. 1B is a schematic exterior view of a radio
`therapy apparatus 1 to which the present invention is
`adapted. As shown, the radiotherapy apparatus 1 includes a
`radiation irradiation apparatus 10 which irradiates an object
`to be examined with radiation from a radiation Source, a
`treatment couch 20 on which the object to be examined P is
`laid down to locate an irradiation region, and a controller
`(not shown) which systematically controls the components
`of the radiotherapy apparatus including the radiation irra
`diation apparatus 10 and the treatment couch 20.
`0033. The radiation irradiation apparatus 10 includes a
`fixed frame, a rotating frame 12, an irradiation head 13, and
`a diaphragm unit 14. The fixed frame 11 is placed on the
`floor and the rotating frame 12 is rotatably mounted to the
`fixed frame. The irradiation head 13 is provided in the tip
`extending perpendicularly to the Surface of the rotating
`frame 12 and equipped with the diaphragm unit 14 for
`shaping a radiation beam and determining a radiation field.
`The configuration of the diaphragm unit 14 will be described
`in detail later.
`0034. The rotating frame 14 is adapted to be rotatable
`about the axis H over nearly 360 degrees. The diaphragm
`unit 14 is also rotatable about the irradiation axis I of
`radiation emitted from the irradiation head 13. The inter
`section of the rotation axis H of the rotating frame 12 and the
`irradiation axis I is referred to as the isocenter IC. The
`rotating frame 12 is constructed to allow not only fixed
`irradiation of radiation but also other forms of irradiation,
`Such as rotating irradiation, Swing irradiation, intermittent
`irradiation, etc.
`0035. The treatment couch 20 is equipped with an upper
`structure 21, a top board 22, a lifting structure 23, and a
`lower structure 24 and is placed on the floor to be rotatable
`over a given range of angles in the direction of arrow G
`along a circle with center at the isocenter IC. The top board
`22, which is a bed on which the object to be examined P
`under examination is laid down, is Supported by the upper
`
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`US 2006/O 198492 A1
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`Sep. 7, 2006
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`structure 21. The upper structure 21 is equipped with mecha
`nisms to move the top board 22 in the forward and backward
`direction indicated by arrow e and in the right and left
`direction indicated by arrow f. The upper structure 21 is
`supported by the lifting structure 23. The lifting structure,
`which is constructed from, for example, a link mechanism,
`lifts the upper structure 21 and the top board 22 over a given
`range by being lifted itself in the up and down direction
`indicated by arrow d. The lifting structure 23 is supported by
`the lower structure 24. The lower structure is equipped with
`a mechanism to rotate the lifting structure 23 in the direction
`indicated by arrow F with center at the position at a distance
`L from the isocenter IC. Thereby, the upper structure 21 and
`the top board 22 can be rotated together with the lifting
`structure 23 through a given angle in the direction of arrow
`F.
`0036). In treatment, the positioning of the object to be
`examined P under examination and setting of the radiation
`field using the diaphragm unit 14 are performed by a medical
`staff D such as a doctor.
`0037
`Diaphragm Unit
`0038. The configuration of the diaphragm unit will be
`described in detail below. In carrying out radiotherapy, it is
`important not to damage normal tissues by applying radia
`tion only to a body region Subjected to treatment, such as a
`malignant tumor, with concentration. The diaphragm unit is
`adapted to control (restrict) the radiation field so as to
`irradiate normal tissues with as little radiation as possible
`and is built into the irradiation head 13 to be rotatable around
`the irradiation axis I.
`0039. The embodiment will be described in terms of a
`split diaphragm unit having multiple diaphragm members
`each in the shape of a circular arc as will be described below.
`However, the principles of the invention is also applicable to
`a split diaphragm unit having multiple diaphragm members
`each in the shape of a rectangle. The configuration of the
`diaphragm unit 14 will be described below with reference to
`FIGS. 2 through 5.
`0040 FIG. 2 is a side view of the diaphragm unit and
`FIG. 3 is another side view in a direction substantially
`normal to FIG. 2. In the practical radiotherapy apparatus 1,
`the diaphragm unit 14 is provided with a housing; however,
`it is omitted in FIGS. 2 and 3 for the sake of description.
`0041. The diaphragm unit 14 is equipped with first and
`second diaphragm members 140A and 140B, second dia
`phragm members 141Ak and 141Bk (k is a natural number
`in the range of 1 to n) each formed in the shape of a leaf, first
`drive units 142A and 142B, second drive units 143Ak and
`143Bk (k is a natural in the range of 1 to n), and a Supporting
`mechanism to be described later.
`0042. The first diaphragm members 140A and 140B are
`placed closer to the radiation Source S than the second
`diaphragm members 141Ak and 141Bk and each consist of
`a single unit made from a heavy metal Such as tungsten. The
`first diaphragm members 140A and 140B are placed so that
`their end surfaces face each other in a first direction (Y
`direction in FIG. 3) with the radiation irradiation axis I
`interposed therebetween. The first diaphragm members
`140A and 140B are driven by the first drive units 142A and
`142B, respectively, to move in the direction of arrow X
`along the orbital plane in the form of a circle with center at
`
`the radiation source S. That is, the first diaphragm members
`140A and 140B are moved to approach each other or
`separate from each other.
`0043. The second diaphragm members 141Akand 141Bk
`are placed more distant from the radiation source S than the
`first diaphragm members 140A and 140B and each consist of
`multiple diaphragm elements (split diaphragm element)
`made from a heavy metal of say, tungsten. The second
`diaphragm members 141Ak and 141Bk are placed so that
`their end surfaces face each other in a second direction (X
`direction in FIG. 2) substantially normal to the first direction
`with the radiation irradiation axis I interposed therebetween.
`The second diaphragm members 141Ak and 141Bk are
`driven by the second drive units 143A and 143B, respec
`tively, to move in the direction of arrow Yalong the orbital
`plane in the form of a circle with center at the radiation
`Source S. That is, the second diaphragm units 141Ak and
`141Bk are moved to approach each other or separate from
`each other. The second drive member 141Ak is comprised of
`a number, n, of diaphragm elements 141A1 to 141An, which
`are densely arranged in the X direction so as to prevent the
`leakage of radiation therefrom. The same holds true for the
`second drive member 141Bk.
`0044 FIG. 4 is a view of the second diaphragm members
`141Ak and 141Bk and the second drive units 143Ak and
`143Bk seen from the side of the radiation source S. As
`shown, drive units 143A1 to 143An and 143B1 to 143 Bn are
`provided for the second diaphragm elements 141A1 to
`141An and 141B1 to 141 Bn, respectively. Therefore, each of
`the diaphragm elements 141A1 to 141An and 141B1 to
`141 Bn is individually driven by a corresponding one of the
`drive units 143A1 to 143An and 143B1 to 143Bn to move
`in the direction of arrow Yalong the orbital plane on a circle
`with center at the radiation source S. The corresponding
`second diaphragm elements 141Ak and 141Bk that face
`each other are driven to approach each other or separate
`from each other.
`0045. Therefore, as shown in FIG. 5, a radiation field U
`of an irregular shape made to approximate the shape of a
`body region to be treated can be formed by moving each of
`the first diaphragm members 140A and 140B in the X
`direction and moving each of the second diaphragm ele
`ments 141Ak and 141Bk in the Y direction so that the
`corresponding diaphragm members or elements facing each
`other approach each other or separate from each other.
`0046) The diaphragm unit 14 is equipped with a support
`ing mechanism for Supporting the second diaphragm mem
`bers 141Ak and 141Bk smoothly and reliably.
`0047 FIG. 6 is a diagram for use in explanation of the
`Supporting mechanism of the second diaphragm members
`141Ak and 141Bk. As shown, each of the diaphragm ele
`ments 141Ak and 141Bk in the diaphragm unit 14 is formed
`with an orbital elongated hole L outside the useful beam
`(that is, outside the portion used to shield radiation). The
`elongated hole is formed along the X direction in the shape
`of a circular arc with center at the radiation source S.
`0048. The diaphragm unit 14 has a supporting member
`144A which penetrates through each of the diaphragm
`elements 141Ak and a supporting member 144B which
`penetrates through each of the second diaphragm elements
`141Bk. Each of the supporting members 114A and 144B is
`
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`comprised of a shaft 145A (145B) and a surface member
`146A (146B) which is a wear-resistant bush 146A (146B)
`and is provided outside the shaft. Note that, the surface
`member 146A (146B) is not limited to the wear-resistant
`bush. For example, a bearing, a collar material or the like
`may be used as the surface member 146A (146B).
`0049. The supporting member 144A (144B) contacts the
`second diaphragm element 141Ak (141Bk) in the peripheral
`portion of the hole L to support it. The inner edge 147A
`(147B) and the outer edge 148Ak (148Bk) are shaped into
`a convex form and Supported by Supporting members (not
`shown) made of a wear-resistant special alloy in the form of
`a comb provided outside the useful beam. Thus, the dia
`phragm element 141Ak (141Bk) has its load in the radial and
`thrust directions Supported at three points by the Supporting
`member 144A (144B) and the comb-shaped members into
`which the inner edge 147Ak (147Bk) and the outer edge
`148Ak (148Bk) are fitted.
`0050. The wear-resistant bush 146A (146B) and the
`comb-shaped supporting members may be formed integrally
`or separately. The comb-shaped supporting members and the
`shaft 145A (145B) may be used for auxiliary purpose. The
`portions where the diaphragm element 141Ak (141Bk) is
`fitted into the comb-shaped supporting members, the inner
`edge 147Ak (147Bk) and the outer edge 148Ak (148Bk)
`may be formed with concave grooves. Rolling contact using
`balls may be used.
`0051 Next, the operation of moving the second dia
`phragm elements 141Ak and 141Bk will be described. The
`second diaphragm element 141Ak (141Bk) is formed with
`teeth on the outer edge. The teeth are engaged with a driving
`gear 151A (151Bk) of a drive unit 143Ak (143Bk) through
`a shaft 150Ak (150Bk) as shown in FIG. 5. The driving gear
`151A (151Bk) is driven by a motor 152Ak (152Bk) as a
`driving Source through a driving force transmission mecha
`nism such as a worm gear 153Ak (153Bk). To detect the
`amount of driving, a potentiometer 154Ak (154Bk) and an
`encoder 155Ak (155Bk) are provided, which function as a
`detector for detecting the position of the diaphragm element
`141Ak (141Bk). Thus, the motor 152Ak (152Bk) is con
`trolled by the controller in the radiotherapy apparatus 1 on
`the basis of information from the potentiometer (154Ak
`(154Bk) and the encoder 155Ak (155Bk), thereby allowing
`the diaphragm element 141Ak (141Bk) to be set in a desired
`position.
`0.052 The surface member 146A (146B) is coated on top
`with a wear-resistant material. Thus, when the second dia
`phragm element 141Ak (141Bk) is moved, abrasion little
`occurs and stable accuracy can be maintained over a long
`period of time. Moderate resistance resulting from slide
`contact allows looseness (backlash) of the diaphragm ele
`ment 141Ak (141Bk) to be minimized.
`0053) The surface member 146A (146B) is set to pen
`etrate through the elongated hole L of the diaphragm ele
`ment 141Ak (141Bk). Therefore, both the ends in the
`direction of length of the elongated hole L serve as mechani
`cal limits in the directions to open or close the diaphragm.
`As the result, the diaphragm element 141Ak (141Bk) is not
`required to have any additional form adapted for mechanical
`limits, allowing the form of the diaphragm element to be
`simplified and the count of parts to be reduced.
`0054. In the split diaphragm unit described above, the
`diaphragm elements 141Ak and 141Bk are formed in the
`
`shape of such a circular arc as shown in FIG. 6. Therefore,
`the shape of the elongated hole L is made to correspond to
`the circular-arc shape (or the locus of movement) of the
`second diaphragm element 141Ak (141Bk). In contrast, with
`a split diaphragm unit having multiple diaphragm elements
`each of a polyhedron (a rectangular form in FIG. 7) having
`a Surface Substantially normal to the radiation axis as shown
`in FIG. 7, the elongated hole L will have a rectangular
`shape. Irrespective of the shape of the diaphragm element
`141Ak (141Bk), the portion where the diaphragm element
`141Ak (141Bk) is fitted into the comb-shaped supporting
`member may be formed into a V- or U-shape as shown in
`FIGS. 8A and 8B. As an auxiliary, small rollers may be
`placed at regularly spaced intervals on the inner and outer
`edges 147Ak (147Bk) along the X-direction and 148Ak
`(148Bk) of the diaphragm element 141Ak (141Bk) to sup
`port it in combination with ball mechanism.
`0055 Subdivision of the second diaphragm member
`141A (141B) (increasing the number of the second dia
`phragm elements) makes it difficult to place the drive units
`143Ak and 143Bk (the drive gears 151Ak 151Bk in par
`ticular). In such a case, the drive units may be placed in the
`form of double structure as shown in FIG. 9, allowing the
`space to accommodate the drive units to be minimized.
`Further, one axis may be tripled as shown in FIG. 10.
`0056 Subdivision of the second diaphragm member
`results in an increase in the number of cables for connecting
`the drive units to a power supply. In such a case, the
`following configuration will allow compact cable accom
`modation and Smooth operation of the diaphragm unit 14
`even if the range of rotation is increased.
`0057 FIG. 11 is a diagram when the diaphragm unit 14
`is viewed from the radiation irradiation surface toward the
`radiation irradiation apparatus 10. A diaphragm element
`frame 40 forming a portion of the diaphragm unit 14 is
`illustrated. The frame 40 is provided at center with an
`irradiation window 41 which allows radiation from the
`radiation source S to pass through.
`0058. The diaphragm frame 40 is provided with a track
`rail 42 on its peripheral portion. The rail 42 has an opening
`corresponding to a central angle which is the same as a given
`angle within which the diaphragm unit 14 is rotationally
`moved with respect to the radiation irradiation apparatus 10
`in a predetermined range. The rail 42 is spread concentri
`cally with the frame 40 on its peripheral portion with that
`central angle.
`0059 A cable processing mechanism 44 is placed on the
`rail 42 so as to be movable on the rail. A first cable 45A for
`the second diaphragm element 141A and a second cable 45B
`for the second diaphragm element 141Bk are inserted in the
`cable processing mechanism 44 so as to be movable in the
`direction of length.
`0060 FIG. 12 is a side view of the structure shown in
`FIG. 11. A rotating frame 46 is placed under the diaphragm
`element frame 40. The diaphragm element frame 40 rotates
`within a given angle as viewed from the rotating frame 46.
`The center of rotation coincides with the central axis of the
`rotating frame 46 and the diaphragm element frame 40. The
`track rail 42 is provided not only on the diaphragm element
`frame 40 but also on the rotating frame 46. On the rotating
`frame 46 the rail 42 is provided in its peripheral portion and
`
`ViewRay Exhibit 1021
`Page 17 of 19
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`

`US 2006/O 198492 A1
`
`Sep. 7, 2006
`
`its central angle and radius are the same as those of the rail
`on the diaphragm element frame 46.
`0061. In such a configuration, the movement in the direc
`tion of length of the first cable 45A causes a rotating roller
`(not shown) to move, which in turn causes the second cable
`45B to move. The first and second cables 45A and 45B are
`guided by the rail 42 and stored in predetermined positions.
`0062) The configuration described above has the follow
`ing utility.
`0063. The radiation diaphragm unit or the radiotherapy
`apparatus of the present invention is configured to Support
`each leaf-shaped diaphragm element through its elongated
`hole as well by a shaft-shaped supporting member. There
`fore, each diaphragm member is Supported in a position
`close to the center of gravity in addition to Support through
`its peripheral portion. As the result, each diaphragm element
`made of heavy metal can be Supported more stably than
`before and highly reliable diaphragm operation can be
`achieved.
`0064. The shaft-shaped supporting member to support a
`diaphragm element in a position close to the center of
`gravity is coated on top with a wear-resistant material. Thus,
`abrasion little occurs and stable accuracy can be maintained
`over a long period of time. Moderate resistance resulting
`from slide contact allows the looseness (backlash) of each
`diaphragm element to be minimized.
`0065. The main configuration is such that an elongated
`hole for track is formed in each diaphragm element and a
`shaft-shaped Supporting member is added which is adapted
`to penetrate through the hole. Therefore, there is no need of
`providing a Supporting part for each diaphragm element and
`a diaphragm unit can be realized which is Smaller and less
`expensive than before. In addition, the burden of adjustment
`and repair can be reduced.
`
`Second Embodiment
`0.066 A second embodiment of the present invention will
`be described next. In this embodiment, the diaphragm unit
`14 is configured such that the surface member 146A (146B)
`can be rotated about the shaft 145A (145B).
`0067 FIG. 13 is a diagram for use in explanation of the
`surface member 146A (146B) and the shaft 145A (145B) in
`the diaphragm unit of this embodiment. As shown, the
`surface member 146A (146B) is adapted to be rotatable
`about the shaft 145A (145B). The second diaphragm element
`141Ak (141Bk) is in contact with the surface member 146A
`(146B) in the peripheral portion of the elongated hole L and
`supported at the point of contact by the surface membe