(19) Japan Patent Office (JP)
`
`
`(12) Japanese Unexamined Patent
`Application Publication (A)
`
`
`
`
`(11) Japanese Unexamined Patent
`Application Publication Number
`
`2003-210595
`(P2003-210595A)
`
`(51) Int. Cl. 7
`
`ID Code
`
` FI
`
` Theme Code (Reference)
`
` A61N 5/10
`
` G21K 1/04
` 5/04
`
` A61N 5/10 K
` G21K 1/04 R
` 5/04 A
`
`4C082
`
`Request for examination: Not yet requested: Number of claims: 5 Online (Total of 9 pages)
`
`
`
`(43) Publication date July 29, 2003
`
`(21) Application number
`
`2002-15698 (P2002-15698)
`
`(71) Applicant
`
`(22) Date of application
`
`January 24, 2002
`
`
`
`
`
`
`
`
`
`
`
`
`
`(72) Inventor
`
`(74) Agent
`
`
`
`000000099
`ISHIKAWAJIMA HARIMA HEAVY IND.
`2-2-1 OTEMACHI, CHIYODA-KU, TOKYO
`
`YAMAZAKI, Shusaku
`c/o Ishikawajima Harima Heavy Ind., Tokyo
`Engineering Center
`3-1-15 Toyosu, Higashi-ku, Tokyo
`
`100062236
`Patent Attorney YAMADA, Hisamitsu (and
`1 other)
`
`Continued on last page.
`
`
`(54) [TITLE OF THE INVENTION]
`Multileaf Collimator and Radiotherapy Apparatus Using
`the Same
`(57) [ABSTRACT]
`[PROBLEM]
`To provide a multileaf collimator, and a radiotherapy
`apparatus, wherein a radiation field is well matched to the
`shape of a lesion.
`[MEANS FOR RESOLUTION]
`The provision of collimator blocks 33 provided in
`multiple stages along the radiation direction D3, wherein
`the collimator blocks 33 are structured through lining up a
`plurality of leaves 35 that can move essentially in parallel
`with the radiation field and leaves 35 of one collimator
`block 33 are disposed shifted so as to be positioned
`between leaves 35 and 35 of another collimator block 33.
`Through this, the pitch of the leaves 35, when viewed from
`the radiation direction D3 is narrowed, enabling refining of
`the shape of the radiation field, enabling the shape of the
`radiation field to be well matched to the shape of a lesion.
`
`
`
`ViewRay Exhibit 1027
`Page 1 of 19
`
`

`

`[PATENT CLAIMS]
`[CLAIM 1]
`A multileaf collimator comprising:
`collimator blocks disposed in multiple stages along the
`direction of radiation, wherein:
`the collimator block is structured through lining up a
`plurality of leaves that are able to move essentially in
`parallel with the radiation field, where the leaves of one
`collimator block are disposed shifted so as to be positioned
`between leaves of another collimator block.
`[CLAIM 2]
`A multileaf collimator as set forth in claim 1, wherein:
`leaves of one collimator block are shifted by 1/2-pitch in
`respect to leaves of another collimator block.
`[Claim 3]
`A multileaf collimator as set forth unit claim 1 or 2,
`wherein:
`a collimator block is structured in a pair so as to have
`linear symmetry on a line that is perpendicular in respect to
`the direction of movement of the leaves, and an opening is
`formed between the pair of collimator blocks through
`movement of the leaves.
`[CLAIM 4]
`A multileaf collimator as set forth in claim 1, 2, or 3,
`wherein:
`a driving source, for moving a leaf, is disposed coaxially
`with the direction of movement of a leaf.
`[CLAIM 5]
`A radiotherapy apparatus that uses a multileaf collimator,
`structured so as to cause a radiation field to match the
`shape of a lesion, through the provision of a multileaf
`collimator as set forth in claim 1, 2, 3, or 4.
`[DETAILED EXPLANATION OF THE INVENTION]
`[0001]
`[FIELD OF TECHNOLOGY OF THE PRESENT INVENTION]
`The present invention relates to a multileaf collimator,
`and to a radiotherapy apparatus that uses the same.
`[0002]
`[PRIOR ART]
`In recent years radiotherapy has been carried out using
`particle beams, such as proton beams and baryon beams, in
`the treatment of cancer, where an example of a
`radiotherapy apparatus for carrying out conventional
`radiotherapy is as depicted in FIG. 6.
`[0003]
`In FIG. 6, 1 is a scatterer, which is a device for
`expanding the beam diameter to the diameter of a radiation
`field so as to enable radiation of the entirety of a lesion 8
`that is to be treated, using a narrow beam, of a diameter of
`several millimeters, that is transported from an accelerator,
`not shown. The scatterer or 1 is a single scatterer, a double
`scatterer, or the like, or the method for expanding the field
`of the beam is may be a wobbler method rather than a
`method that uses a scatterer 1.
`[0004]
`2 is a fine degrader, which is a device that is disposed
`below the scatterer 1 so as to adjust the radiation depth by
`reducing the beam energy in respect to the lesion 8 to be
`single through insertion into the radiation field of the beam
`3 that is formed through expansion by scattering by the
`scatterer 1, structured from a light atomic element.
`Moreover, the fine degrader 2 comprises an offset adjusting
`
`Japanese Unexamined Patent Application Publication 2003-210595
`(2)
`
`mechanism so as to enable switching of the thickness, when
`viewed from the direction of radiation of the beam 3. The
`adjustment to the depth of radiation may instead be through
`adjusting the energy through the accelerator, rather than
`using the fine degrader 2.
`[0005]
`4 is a ridge filter, a device that is disposed below the fine
`degrader 2, so as to apply energy modulation to the beam 3,
`which is of a single energy (velocity), in order to apply the
`radiation dose uniformly in the depth direction of the lesion
`8 that is being treated That is, the beam 3 that is transported
`from the accelerator is of a small energy tolerance (for
`example, ± 0.1%), and when the lesion 8 is irradiated
`directly thereby, it is necessary to modulate the beam 3 in
`order to apply a radiation dose that is concentrated into a
`region that is narrow in the depth direction (between, for
`example, several millimeters and 1 cm), and a ridge filter 4
`is used for this modulation. A rotary modulator may be
`used instead of the ridge filter 4.
`[0006]
`5 is a four-leaf first collimator configured so as to enable
`adjustment of the area of an opening portion, a device
`disposed below the ridge filter, in order to prevent
`application of the radiation dose to healthy tissue
`surrounding the lesion 8 that is to be treated. The first
`collimator 5 is configured so as to collimate the beam 3 so
`as to roughly match the shape of the lesion 8 that is to be
`treated, when viewed from the radiation direction of the
`beam 3. The thickness of the first collimator 5 is a
`thickness that completely blocks the particle beam that
`could otherwise radiate outside of the lesion 8 that is to be
`treated.
`[0007]
`6 is a bolus, a device that is disposed below the first
`collimator 5 so as to function as a compensating filter for
`matching, to the bottom of the lesion 8 that is to be treated,
`the boundary with which the radiation dose is to be applied
`and a compensating filter for eliminating the effects of
`nonuniformities in the bones, skin, and the like, of the
`patient.
`[0008]
`7 is a multileaf collimator of the final collimator wherein
`the area of the opening portion is fixed, structured so as to
`produce the shape of the lesion 8 that is to be treated. The
`thickness of the multileaf collimator 7 is also a thickness
`that perfectly blocks the particle beam that could irradiate
`outside of the lesion 8 that is to be treated.
`[0009]
`When performing radiotherapy on a lesion 8 using the
`radiotherapy apparatus described above, first a narrow
`beam 3 with a diameter of about several millimeters,
`transported from an accelerator, not shown, is expanded by
`a scatterer 1, to become a beam 3 with a radiation field
`width able to radiate the entirety of the lesion 8 that is to be
`treated, where the radiation depth of the expanded beam 3
`is adjusted by the ridge filter 4, and then collimated, by the
`first collimator 5, to roughly match the size of the lesion 8.
`[0010]
`Additionally, the beam 3, having been collimated by the
`first collimator 5, is transported to the bolus 6, where the
`radiation dose that is to be applied to the lesion 8 that is to
`be treated is adjusted by the bolus 6 so as to match the
`
`
`
`ViewRay Exhibit 1027
`Page 2 of 19
`
`

`

`boundary at the bottom of the lesion 8, and adjusted so as
`to eliminate the effects of nonuniformities in the bones and
`skin of the patient, followed by adjustment, by the multileaf
`collimator 7, so as to match the shape of the lesion 8 that is
`to be treated, after which the entirety of the lesion 8 is
`irradiated thereby.
`[0011]
`Here the multileaf collimator 7 for adjusting the beam 3
`may be of a variety of shapes, where examples of multileaf
`collimators 7 are as depicted in FIG. 7 through FIG. 10,
`where a pair of left and right collimator blocks 9, divided in
`two in the crosswise direction D1 so as to be linearly
`symmetrical in respect to a reference line S that is a line
`that passes through the radiation axis O of the beam 3 is
`provided, where each individual collimator block 9 is
`structured through multiple strip-shaped leaves 10 that are
`lined up in the front/rear direction D2 (the direction of the
`reference line S), which is the direction that is
`perpendicular to the crosswise direction D1. That is, in
`each individual leaf 10, rack grooves 11 are formed in the
`top end face that extends in the crosswise direction D1, and
`protruding portions 12, of a labyrinthine structure, are
`formed on a side face that is essentially parallel with the
`radiation direction D3 of the beam 3, bent at positions in
`the middle in the radiation direction (the thickness
`direction) D3 of the beam 3. Additionally, in the leaf 10, a
`lower portion 13 is supported on a lower guide member 14
`and an upper portion 15 is supported on an upper guide
`member 16, and the rack grooves 11 are meshed, through
`gears 18, with motors 17 that are to the side of the leaves
`10, enabling adjustment of the positions thereof in the
`crosswise direction D1 (the direction in the line that is
`perpendicular to the reference line S), to correspond to the
`individual lesion 8. Moreover, in FIG. 8, 19 indicates a gap
`that is positioned between the leaves 10 and 10.
`[0012]
`When performing radiotherapy on the lesion 8 using this
`multileaf collimator 7, first the leaves 10 are moved by the
`motors 17 to determine the radiation field (the radiation
`range of the beam 3) by forming an opening 20 that
`essentially matches the shape of the lesion 8 on the
`reference line S of the multileaf collimator 7, to irradiate
`the lesion 8, through the opening 20 of the multileaf
`collimator 7, with the beam 3, through the scatterer 1, the
`fine degrader 2, the ridge filter 4, the first collimator 5, and
`the bolus 6, depicted in FIG. 6.
`[0013]
`Here, when the beam 3 passes through the opening 20 of
`the multileaf collimator 7, the beam 3 is blocked at the
`upper portions 15 and the protruding portions 12, as
`depicted in FIG. 10, of the other parts of the multileaf
`collimator 7.
`[0014]
`On the other hand, as depicted in FIG. 11 and FIG. 12, a
`multileaf collimator 21 of another example comprises a pair
`of left and right collimator blocks 23 that are structured
`through many strip-shaped leaves 22, in essentially the
`same manner as in the example above, where in each of the
`leaves 22, rack grooves 24 are formed on a top end face
`that extends in the crosswise direction, and a plurality of
`protruding portions 25 of a corrugated structure is formed
`on a side face that is essentially parallel to the radiation
`
`Japanese Unexamined Patent Application Publication 2003-210595
`(3)
`
`direction of the beam 3, bending alternatingly to the front
`and rear directions D2, along the radiation direction
`(thickness direction) D3 of the beam 3. Additionally, in the
`leaf 22, a lower portion 26 is supported on a lower guide
`member 27 and an upper portion 28 is supported on an
`upper guide member 29, and the rack grooves 24 are
`caused to mesh, through a gear 30, with a motor (not
`shown), to enable adjustment of the position in the
`crosswise direction so as to match the individual lesion 8.
`Moreover, in the figure, 31 indicates a gap that is
`positioned between leaves 22 and 22.
`[0015]
`When performing radiotherapy on the lesion 8 using this
`multileaf collimator 21, first, in the same manner as in the
`example described above, the leaves 22 are moved by the
`motors 17 to determine the radiation field (the radiation
`range of the beam 3) by forming an opening (not shown)
`that essentially matches the shape of the lesion 8 on the
`reference line S of the multileaf collimator 21, to irradiate
`the lesion 8, through the opening 20 of the multileaf
`collimator 21, with the beam 3, through the scatterer 1, the
`fine degrader 2, the ridge filter 4, the first collimator 5, and
`the bolus 6, depicted in FIG. 6.
`[0016]
`Here, when the beam 3 passes through the opening of the
`multileaf collimator 21 in this other example, in the other
`parts of the multileaf collimator 21, as depicted in FIG. 12,
`the beam 3 is blocked by the upper portion 28 by the
`plurality of protruding portions 25.
`[0017]
`[PROBLEM SOLVED BY THE PRESENT INVENTION]
`However, the smoothness of the periphery of the opening
`20 that is formed through the conventional multileaf
`collimators 7 and 21 is dependent on the pitch and widths
`of the leaves 10 and 22, and thus it is not been possible to
`match well the radiation field to the shape of the lesion 8
`through the opening 20, and thus there was the possibility
`of adverse effects on the tissue on the periphery of the
`lesion 8 during radiotherapy. Moreover, the leaves 10 and
`22 of the conventional multileaf collimators 7 and 21 have
`complex shapes, equipped with protruding portions 12 of a
`labyrinthine structure on the side faces, or protruding
`portions 25 of a corrugated structure, and thus machining
`has been difficult, so there was a problem in that the
`manufacturing cost was extremely high. Moreover, when
`closing the opening 20 through bringing a pair of
`collimator blocks 9 into proximity therewith, there was a
`problem in that the beam 3 would leak from the closed
`opening 20, as in the opening 20 of the multileaf collimator
`7 in the example above, depicted in FIG. 13.
`[0018]
`In contemplation of the situation described above, the
`object of the present invention is to provide a multileaf
`collimator, and a radiotherapy apparatus, wherein a
`radiation field is well matched to the shape of a lesion.
`[0019]
`[MEANS FOR SOLVING THE PROBLEm]
`Claim 1 of the present invention relates to a multileaf
`collimator comprising: collimator blocks disposed in
`multiple stages along the direction of radiation, wherein:
`the collimator block is structured through lining up a
`plurality of leaves that are able to move essentially in
`
`
`
`ViewRay Exhibit 1027
`Page 3 of 19
`
`

`

`parallel with the radiation field, where the leaves of one
`collimator block are disposed shifted so as to be positioned
`between leaves of another collimator block.
`[0020]
`Claim 2 of the present invention relates to a multileaf
`collimator as set forth in claim 1, wherein: leaves of one
`collimator block are shifted by 1/2-pitch in respect to
`leaves of another collimator block.
`[0021]
`Claim 3 of the present invention relates to a multileaf
`collimator as set forth unit claim 1 or 2, wherein: a
`collimator block is structured in a pair so as to have linear
`symmetry on a line that is perpendicular in respect to the
`direction of movement of the leaves, and an opening is
`formed between the pair of collimator blocks through
`movement of the leaves.
`[0022]
`Claim 4 of the present invention relates to a multileaf
`collimator as set forth in claim 1, 2, or 3, wherein: a driving
`source, for moving a leaf, is disposed coaxially with the
`direction of movement of a leaf.
`[0023]
`Claim 5 of the present invention relates to a radiotherapy
`apparatus that uses a multileaf collimator, structured so as
`to cause a radiation field to match the shape of a lesion,
`through the provision of a multileaf collimator as set forth
`in claim 1, 2, 3, or 4.
`[0024]
`In the present invention, collimator blocks are provided
`in multiple stages along the direction of radiation, where
`leaves of one collimator block are disposed shifted so as to
`be positioned between the leaves of another collimator
`block, thus narrowing the pitch or width of the leaves,
`when viewed from the radiation direction, enabling
`refinement of the shape of the radiation field. Additionally,
`because the leaves in one collimator block are positioned
`between the leaves of the other collimator block, the gap
`between leaves in the direction of radiation can be closed
`reliably, and the leaves can have simple shapes, wherein it
`is unnecessary to have recessed and protruding portions in
`the leaves, thus making machining easy, and enabling a
`reduction in the manufacturing cost.
`[0025]
`As in claim 2 of the present invention, when the leaves
`of one collimator block are disposed shifted by 1/2-pitch
`relative to the leaves of the other collimator block, the pitch
`and width of the leaves, when viewed from the radiation
`direction, are minimized, enabling further refinement of the
`shape of the radiation field.
`[0026]
`As in claim 3 of the present invention, when the
`collimator blocks are structured in a pair, so as to be
`linearly symmetrical on a line that is perpendicular in
`respect to the direction of movement of the leaves, and so
`as to enable formation of an opening between the pair of
`collimator blocks through movement of the leaves, then,
`when closing the opening, the parts of the opening that are
`closed by one of the pair of column or blocks and the parts
`of the opening that are closed by the other of the pair of
`collimator blocks are arranged so as to be mutually
`different, making possible to reduce the leakage of
`radiation from the parts of the opening that are closed.
`
`Japanese Unexamined Patent Application Publication 2003-210595
`(4)
`
`[0027]
`As in claim 4 of the present invention, because the
`driving sources for moving the leaves are provided
`coaxially with the direction of movement of the leaves, the
`driving sources are disposed so as to not interfere with
`adjacent leaves, thus enabling the leaves to be positioned
`easily, further reducing the manufacturing cost and
`enabling an improvement in the degrees of freedom with
`which the leaves can be positioned.
`[0028]
`As in claim 5 of the present invention, when the
`radiotherapy apparatus is structured so as to match the
`radiation field to the shape of the lesion through the
`provision of a multileaf collimator as set forth in claim 1, 2,
`3, or 4, the shape of the radiation field is refined so as to
`cause the radiation field to match well the shape of the
`lesion, thus making it possible to prevent well adverse
`effects on the tissue surrounding the lesion during
`radiotherapy.
`[0029]
`[EMBODIMENT OF THE PRESENT INVENTION]
`An embodiment according to the present invention will
`be explained below, together with the illustrated examples.
`[0030]
`FIG. 1 through FIG. 5 are an example embodiment of a
`multileaf collimator according to the present invention, and
`of a radiotherapy apparatus that uses the same.
`[0031]
`As depicted in FIG. 1 through FIG. 5, the radiotherapy
`apparatus comprises a multileaf collimator 32, where the
`multileaf collimator 32 is equipped with an upper
`collimator block 33 and a lower collimator block 33,
`equipped in two stages, upper and lower, along the
`radiation direction D3 of the beam 3 (the radiation), where
`each of the individual upper and lower collimator blocks 33
`and 33 are configured in left and right pairs, divided in two
`in the crosswise direction D1, so as to be linearly
`symmetrical in respect to a reference line S that is the line
`that passes through the radiation axis O of the beam 3,
`where positions of each of the left/right here are structured
`from a large number of strip-shaped leaves 35 that are lined
`up, with prescribed gaps 34 therebetween, in the front/rear
`direction D2 (the direction of the reference line S), which is
`perpendicular in respect to the crosswise direction D1. Here
`the gaps 34 that are positioned between the leaves 35 and
`35 may have any spacing, insofar as it is spacing that is
`narrower than the widths of the leaves 35.
`[0032]
`The leaves 35 that structure each of the upper and lower
`collimator blocks 33 are formed extending in the crosswise
`direction D1, where the leaves 35 of the lower collimator
`block 33, when viewed from the radiation direction D3 of
`the beam 3, are disposed in a staggered pattern that is
`shifted by 1/2-pitch in respect to the leaves 35 of the
`collimator block 33 of the upper stage so as to be
`positioned between the leaves 35 in the collimator block 33
`of the upper stage, to close the gaps 34. Here the leaves 35
`of the collimator block 33 of the lower stage are supported,
`in the vertical direction, by center guide members 37 and
`lower guide members 38 of a supporting frame 36, and also
`the leaves 35 of the collimator block 33 of the upper stage
`are supported in the vertical direction by center guide
`
`
`
`ViewRay Exhibit 1027
`Page 4 of 19
`
`

`

`Japanese Unexamined Patent Application Publication 2003-210595
`(5)
`
`members 37 and upper guide members 39 of the supporting
`frame 36, and disposed so as to enable movement in the
`crosswise direction D1 (the direction of a line that is
`perpendicular to the reference line S).
`[0033]
`Additionally, the leaf 35 is provided with a nut 41 in a
`fastening groove 40, through formation the fastening
`groove 40 on the outside face thereof, where a screw rod 43,
`which is supported on a bearing 42, on the supporting
`frame 36, so as to enable rotation, is secured in the nut 41,
`and a motor 45 that is a driving source that can rotate the
`screw rod 43 through a coupling 44, is provided on the
`outside of the screw rod 43. Here the motor 45 that is the
`driving source is supported by the connecting member 46
`that is secured to the supporting frame 36, so as to be
`positioned coaxially with the direction of movement of the
`leaf 35.
`[0034]
`The operation of the example embodiment that embodies
`the present invention will be explained below.
`[0035]
`When performing radiotherapy on the lesion 8 through
`the radiotherapy apparatus that uses the multileaf
`collimator 32, first the leaves 35 are moved through the
`screw rods 43 and the nuts 41 through driving the motors
`45, to form an opening 47 that essentially matches the
`shape of the lesion 8, on the reference line S of the
`multileaf collimator 32, to define the radiation field (the
`range of radiation of the beam 3), and the beam 3, which
`passes through the scatterer 1, the fine degrader 2, the ridge
`filter 4, the first collimator 5, and the bolus 6, depicted in
`FIG. 6, radiates the lesion 8 through the opening 47 of the
`multileaf collimator 32.
`[0036]
`Here, when the beam 3 passes through the opening 47 of
`the multileaf collimator 32, the other parts of the multileaf
`collimator 32, as depicted in FIG. 4, blocks the beam 3 by
`the leaves 35 of the upper multileaf collimator 32, and
`blocks by the leaves 35 of the lower multileaf collimator 32,
`the beam 3 that passes through the gaps 34 between the
`leaves 35 and 35.
`[0037]
`Through disposing the collimator blocks 33 in upper and
`lower stages, along the radiation direction D3, in this way,
`and positioning the leaves 35 of the lower collimator block
`33 at the positions between the leaves 35 and 35 of the
`upper collimator block 33, the pitch and widths of the
`leaves 35, when viewed from the radiation direction D3,
`are made narrower, refining the shape of the radiation field,
`enabling an improvement in the smoothness of the
`periphery of the opening 47. Moreover, the leaves 35 of the
`lower collimator block 33 are positioned between the
`leaves 35 and 35 of the upper collimator block 33, reliably
`blocking the gaps 34 between the leaves 35 and 35, in
`respect to the radiation direction D3, and also eliminating
`the need for the recessed and protruding portions in the
`leaves 35, enabling the leaves 35 to be of a simple shape,
`enabling machining to be easy, and enabling a reduction in
`manufacturing costs.
`[0038]
`When the leaves 35 of the lower collimator block 33 are
`shifted by 1/2-pitch in respect to the leaves 35 of the upper
`
`collimator block 33, the pitch and width of the leaves 35,
`when viewed from the radiation direction D3, are narrowed,
`enabling the shape of the radiation field to be refined
`further.
`[0039]
`The collimator blocks 33 are structured in pairs, so as to
`have linear symmetry on a line that is perpendicular to the
`direction of movement of the leaves 35, and structured so
`as to enable formation of an opening 47 between the pairs
`of collimator blocks through movement of the leaves 35,
`and when the opening 47 is closed, the parts of the opening
`47 that are blocked by the lower pair of collimator blocks
`33 and 33 and the parts of the opening 47 that are blocked
`by the upper pair of collimator blocks 33 and 33 are
`arranged so as to be mutually different, reducing leakage of
`radiation from the closed parts of the opening 47, enabling
`the radiation to be used appropriately.
`[0040]
`When the motors 45 for moving the leaves 35 are
`provided coaxially with the direction of movement of the
`leaves 35, the arrangement of the motors 45 will be an
`arrangement that will not interfere with the adjacent leaves
`35, enabling the leaves 35 to be positioned easily, further
`reducing the manufacturing costs, and enabling an
`improvement in the degrees of freedom of placement of the
`leaves 35.
`[0041]
`When a radiotherapy apparatus is structured so as to
`match the radiation field to the shape of the lesion 8,
`through the provision of the multileaf collimator 32, the
`shape of the radiation field can be refined, enabling the
`radiation field to be matched well to the shape of the lesion
`8, thereby preventing well adverse effects on tissue
`surrounding the lesion 8 during radiotherapy.
`[0042]
`Note that in the illustrated example of the present
`invention, the leaves of the upper collimator blocks and the
`leaves of the lower collimator blocks need not be identical,
`but rather may be of different sizes and shapes, and the
`shifted layout of the leaves is not limited to positioning
`with 1/2-pitch shifts, but rather may be at any positions
`insofar as the gaps between leaves are blocked, and, of
`course, various modifications can be applied within a range
`that does not deviate from the spirit or intent of the present
`invention.
`[0043]
`[EFFECTS OF THE INVENTION]
`The multileaf collimator according to the present
`invention, and the radiotherapy apparatus using the same,
`has a variety of advantageous effects, as described below:
`[0044]
`I) When the collimator blocks are disposed in multiple
`stages along the radiation direction, where the leaves of one
`collimator block are positioned between the leaves of the
`other collimator block, disposed with a shift, the pitch and
`width of the leaves, when viewed in the radiation direction,
`are narrower, enabling refinement of the shape of the
`radiation field. Additionally, the leaves of one collimator
`block are positioned between the leaves of the other
`collimator block, thus blocking reliably the gaps between
`the leaves, in respect to the radiation direction, and
`eliminating the need for raised and recessed portions in the
`
`
`
`ViewRay Exhibit 1027
`Page 5 of 19
`
`

`

`Japanese Unexamined Patent Application Publication 2003-210595
`(6)
`
`leaves, simplifying the shapes of the leaves, enabling easy
`machining, thus enabling a reduction in manufacturing
`costs.
`[0045]
`II) When, as in claim 2 of the present invention, the
`leaves of one collimator block are disposed shifted by 1/2-
`pitch in respect to the leaves of another collimator block,
`the pitch and width of the leaves, when viewed in the
`radiation direction, are minimized, enabling further
`refinement of the shape of the radiation field.
`[0046]
`III) When, as in claim 3 of the present invention, the
`collimator blocks are structured in pairs so as to be linearly
`symmetrical on a line that is perpendicular in respect to the
`direction of movement of the leaves, and structured so as to
`enable formation of an opening between the pairs of
`collimator block through movement of the leaves, then
`when the opening is closed, the parts of the opening that are
`blocked by one of the pair of collimator blocks and the
`parts where the opening is closed by the other of the pair of
`collimator block are arranged so as to be mutually different,
`making possible to reduce leakage of radiation from the
`parts wherein the openings are block.
`[0047]
`IV) When, as in claim 4 of the present invention, the
`driving sources for moving the leaves are equipped
`coaxially with the direction of movement of the leaves, the
`arrangement of the driving sources will not interfere with
`the adjacent leaves, enabling the leaves to be positioned
`easily, and further reducing the manufacturing cost, while
`also enabling an improvement in the degree of freedom for
`positioning of the leaves.
`[0048]
`V) When, as in claim 5 of the present invention, a
`radiotherapy apparatus is structured so as to cause the
`radiation field to match the shape of a lesion, through a
`multileaf collimator as set forth in claim 1, 2, 3, or 4, the
`shape of the radiation field can be refined, enabling the
`radiation field to match well the shape of the lesion, thus
`making it possible to prevent well an adverse effect on the
`tissue surrounding the lesion during radiotherapy.
`
`[FIG. 1]
`
`[BRIEF DESCRIPTIONS OF THE DRAWINGS]
`FIG. 1 is a plan view depicting an embodiment of a
`multileaf collimator according to the present invention.
`FIG. 2 is a view in the direction of the arrow II-II in FIG.
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`1.
`
`FIG. 3 is a view in the direction of the arrow III-III in
`FIG. 2.
`FIG. 4 is a schematic diagram depicting a state wherein
`the multileaf collimator of FIG. 2 is irradiated.
`FIG. 5 is a schematic view depicting a state wherein the
`multileaf collimator is irradiated, in the direction of V-V in
`FIG. 1.
`FIG. 6 is a front view depicting an overview of a typical
`radiotherapy apparatus.
`FIG. 7 is a plan view depicting an example of a
`conventional multileaf collimator.
`FIG. 8 is a view in the direction of VIII-VIII in FIG. 7.
`FIG. 9 is a plan view depicting the arrangement of
`motors in a conventional multileaf collimator.
`FIG. 10 is a schematic diagram detecting the state
`wherein the multileaf collimator of FIG. 8 is irradiated.
`FIG. 11 is a front view depicting another example of a
`conventional multileaf collimator.
`FIG. 12 is a schematic diagram depicting a state wherein
`the multileaf collimator of FIG. 11 is irradiated.
`FIG. 13 is a schematic diagram depicting a state wherein
`the multileaf collimator of FIG. 7 is irradiated in the
`direction XIII-XIII.
`[EXPLANATION OF REFERENCE SYMBOLS]
`3: Beam (Radiation)
`8: Lesion
`32: Multileaf Collimator
`33: Collimator Block
`34: Gap
`35: Leaf
`45: Motor (Driving Source)
`47: Opening
`D3: Radiation Direction
`S: Reference Line (Perpendicular Line)
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`[FIG. 4]
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`Page 6 of 19
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`[FIG. 9]
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`[FIG. 5]
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`Japanese Unexamined Patent Application Publication 2003-210595
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`[FIG. 2]
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`[FIG. 3]
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`[FIG. 11]
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`[FIG. 6]
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`[FIG. 7]
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`Japanese Unexamined Patent Application Publication 2003-210595
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`[FIG. 8]
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`[FIG. 13]
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`[FIG. 10]
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`[FIG. 12]
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`Japanese Unexamined Patent Application Publication 2003-210595
`(9)
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`
`Continued from Front Page
`(72)
`KANESHIMA, Yoshiharu
`Inventor
`c/o Ishikawajima Harima Heavy Ind.,
`Tokyo Engineering Center
`3-1-15 Toyosu, Higashi-ku, Tokyo
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`(72) Inventor
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`(72) Inventor
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`F Terms
`(Reference)
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`AZUMA, Osamu
`c/o Ishikawajima Harima Heavy Ind.,
`Yokohama Engineering Center
`1 Shinnakahara-chu, Isogo-ku, Yokohama
`City, Kanagawa Prefecture
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`TEZUKA, Atsushi
`c/o Ishikawajima Harima Heavy Ind., Tokyo
`Engineering Center
`3-1-15 Toyosu, Higashi-ku, Tokyo
`
`4C082 AA01 AC02 AC05 AE01 AG24
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`Page 9 of 19
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`CERTIFICATE OF TRANSLATION
`
`I, Doctor Warren Smith, residing at 27 Sandybrook Dr., Durham, NH, hereby state that:
`
`(1) I know both the English and Japanese languages;
`
`(2) I have read both Japanese Unexamined Patent Application Publication No.: 2003-210595,
`and the atta