JP2017192669A - Charged particle beam therapy apparatus and ridge filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charged particle beam therapy apparatus and a ridge filter capable of approximating a spread-out Bragg peak to desired characteristics.SOLUTION: A ridge filter 22 includes: a plurality of fins 12 aligned in an X axis direction (a width direction) orthogonal to a Z axis direction (an irradiation direction of a charged particle beam); and a base part 11 for supporting the fins 12. In the configuration, the fins 12 are integrally formed with the base part 11. Thereby, position accuracy between the fins 12 and the base part 11 can be improved. The improvement in the position accuracy between the fins 12 and the base part 11 causes the charged particle beam R to pass through a desired position of the fins 12. This configuration can thus approximate a spread-out Bragg peak to desired characteristics.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a charged particle beam therapy apparatus and a ridge filter.

  Conventionally, a charged particle beam therapy apparatus that irradiates a charged particle beam is known. Such a charged particle beam therapy apparatus may have a ridge filter for generating an enlarged Bragg peak of a charged particle beam (see, for example, Patent Document 1).

JP 10-314324 A

  In the charged particle beam therapy system as described above, the ridge filter has a plurality of fins arranged side by side in the width direction and a base portion that supports the fins. Here, when attaching a fin with respect to a base part, if a shift | offset | difference arises between a fin and a base part, there exists a problem that an expansion Bragg peak will shift | deviate from a desired characteristic.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a charged particle beam therapy apparatus and a ridge filter capable of bringing an enlarged Bragg peak close to a desired characteristic.

  The charged particle beam therapy apparatus according to the present invention includes an accelerator that accelerates charged particles and emits the charged particle beam, and a ridge filter that generates an enlarged Bragg peak of the charged particle beam, and the charged particle beam is applied to the irradiated object. An irradiating unit that irradiates and a transport line that transports the charged particle beam emitted from the accelerator to the irradiating unit, and the ridge filter is arranged in a plurality of width directions that are orthogonal to the irradiation direction of the charged particle beam. The fin has a base portion that supports the fin, and the fin is formed integrally with the base portion.

  In the charged particle beam therapy system according to the present invention, the ridge filter includes a plurality of fins arranged in a width direction that is a direction orthogonal to the irradiation direction of the charged particle beam, and a base portion that supports the fins. . In such a configuration, the fin is formed integrally with the base portion. Therefore, the positional accuracy between the fin and the base portion can be improved. By improving the positional accuracy between the fin and the base portion, the charged particle beam can pass through a desired position of the fin. Thereby, an expansion Bragg peak can be brought close to a desired characteristic.

  Moreover, the fin located in the outermost side in the width direction among several fins may incline toward the center side in the width direction. The charged particle beam is incident on the outer fin in the width direction while being inclined from the base axis. Accordingly, correspondingly to this, at least the outermost fin in the width direction tilts toward the center in the width direction, so that the distance that the charged particle beam passes through the fin can be made closer to a desired value. it can. Thereby, an expansion Bragg peak can be brought close to a desired characteristic.

  Moreover, the inclination angle of the fin may be larger as the fin is located on the outer side in the width direction. The charged particle beam has a greater inclination from the base axis toward the outer side in the width direction, so that the inclination angle of the fin can correspond to the inclination of the charged particle beam.

  Moreover, when the axis line which passes through the center is set with respect to each fin, the fin may be inclined so that each axis line intersects at a preset point. With such a configuration, the inclination angle of each fin can correspond to the inclination of the charged particle beam.

  Further, among the plurality of fins, at least the fin located at the outermost side in the width direction is lower than the height of the fin located at the central side, and the density of the fins located at the outer side is higher than the fin located at the central side. The fin located on the center side may be formed integrally with the base portion. With such a configuration, the attenuation can be adjusted according to the inclination of the charged particle beam by adjusting the height and density of the fins on the outer side in the width direction where the inclination of the charged particle beam becomes large. On the other hand, on the inner side in the width direction where the inclination of the charged particle beam becomes small, the fin position accuracy can be improved by forming the fin integrally with the base portion.

  A ridge filter according to the present invention is a ridge filter for a charged particle beam therapy system that generates an enlarged Bragg peak of a charged particle beam, and a plurality of ridge filters arranged in a width direction that is orthogonal to the irradiation direction of the charged particle beam. The fin has a base portion that supports the fin, and the fin is formed integrally with the base portion.

  According to the ridge filter according to the present invention, the same operation and effect as the above-mentioned charged particle beam therapy system can be obtained.

  According to the present invention, the enlarged Bragg peak can be brought close to a desired characteristic.

FIG. 1 is a sectional view of a building in which a charged particle beam therapy system according to an embodiment of the present invention is installed. FIG. 2 is a perspective view showing a configuration in the vicinity of the irradiation unit of the charged particle beam therapy system according to the embodiment of the present invention. FIG. 3 is a schematic configuration diagram of the charged particle beam therapy system according to the embodiment of the present invention. It is a schematic block diagram of the irradiation part shown in FIG. It is an expanded sectional view of the ridge filter shown in FIG. It is the figure which looked at the ridge filter shown in FIG. 4 from the Z-axis direction negative side. It is an expanded sectional view of the ridge filter concerning a modification.

  Hereinafter, a charged particle beam therapy system and a ridge filter according to the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a sectional view of a building in which a charged particle beam therapy system according to an embodiment of the present invention is installed. FIG. 2 is a perspective view showing a configuration in the vicinity of the irradiation unit of the charged particle beam therapy system according to the embodiment of the present invention. FIG. 3 is a schematic configuration diagram of the charged particle beam therapy system according to the embodiment of the present invention. As shown in FIG. 3, the charged particle beam therapy system 1 irradiates a charged particle beam R to a tumor (irradiated body) 14 in the body of a patient 13. The charged particle beam R is obtained by accelerating charged particles at high speed, and examples thereof include a proton beam, a heavy particle (heavy ion) beam, and an electron beam.

  In the following description, the terms “X-axis direction”, “Y-axis direction”, and “Z-axis direction” will be used. The “Z-axis direction” is a direction in which the base axis AX of the charged particle beam R extends. The “base axis AX” is an irradiation axis of the charged particle beam R when it is not deflected by scanning electromagnets 3a and 3b described later. FIG. 3 shows a state where the charged particle beam R is irradiated along the base axis AX. In the following description, it is assumed that the direction in which the charged particle beam R is irradiated along the base axis AX is the “irradiation direction of the charged particle beam R”. The “X-axis direction” is one direction in a plane orthogonal to the Z-axis direction. The “Y-axis direction” is a direction orthogonal to the X-axis direction in a plane orthogonal to the Z-axis direction.

  As shown in FIGS. 1 and 3, the charged particle beam therapy system 1 includes an accelerator 2, a rotating gantry 3 including an irradiation unit (irradiation nozzle) 8, a transport line 40, and a control device 7. . As shown in FIG. 1, the charged particle beam therapy apparatus 1 is installed in a building. In the example shown in FIG. 1, the building is a building of a plurality of floors (here, the second floor), and the accelerator 2 and the rotating gantry 3 are installed in the rooms of the respective layers. The transport line 40 is provided over each level of the building, and connects the accelerator 2 and the irradiation unit 8 (see FIG. 2) of the rotating gantry 3. The irradiation direction of the charged particle beam by the irradiation unit 8 can be changed by the rotation of the rotating gantry 3.

  The accelerator 2 accelerates the charged particles and emits a charged particle beam R. Examples of the accelerator 2 include a cyclotron, a synchrotron, a cyclosynchrotron, and a linac. The charged particle beam R generated by the accelerator 2 is transported to the irradiation unit 8 by the transport line 40. The accelerator 2 is connected to a control device 7 and its operation is controlled by the control device 7.

  The transport line 40 is a line for transporting the charged particle beam R emitted from the accelerator 2 to the irradiation unit 8. The transport line 40 is provided with a plurality of deflection electromagnets (not shown).

  The irradiation unit 8 includes scanning electromagnets 3a and 3b, monitors 4a and 4b, a scatterer 5, a ridge filter 22, a degrader 30, a multi-leaf collimator 24, a bolus 26, and a patient collimator 27. The degrader 30 and the patient collimator 27 may be omitted.

  The scanning electromagnets 3a and 3b are each composed of a pair of electromagnets, change the magnetic field between the pair of electromagnets according to the current supplied from the control device 7, and scan the charged particle beam R passing between the electromagnets. The X-axis direction scanning electromagnet 3a scans the charged particle beam R in the X-axis direction, and the Y-axis direction scanning electromagnet 3b scans the charged particle beam R in the Y-axis direction. These scanning electromagnets 3 a and 3 b are arranged in this order on the base axis AX and downstream of the accelerator 2.

  The monitor 4a monitors the beam position of the charged particle beam R, and the monitor 4b monitors the absolute value of the dose of the charged particle beam R and the dose distribution of the charged particle beam R. Each of the monitors 4a and 4b outputs the monitored monitoring information to the control device 7. The monitor 4a is disposed on the base axis AX of the charged particle beam R and downstream of the accelerator 2 and upstream of the X-axis direction scanning electromagnet 3a. The monitor 4b is disposed on the base axis AX and downstream of the degrader 30. However, the positions of the monitors 4a and 4b are not particularly limited.

  The scatterer 5 diffuses the passing charged particle beam R into a wide beam having a spread in a direction orthogonal to the irradiation axis. The scatterer 5 has a plate shape and is formed of, for example, tungsten having a thickness of several millimeters. The scatterer 5 is arranged on the upstream side of the monitor 4b on the downstream side of the scanning electromagnet 3b on the base axis AX.

  The ridge filter 22 adjusts the dose distribution of the charged particle beam R. Specifically, the ridge filter 22 gives an enlarged Bragg peak (SOBP) to the charged particle beam R so as to correspond to the thickness (length in the irradiation direction) of the tumor 14 in the body of the patient 13. Thereby, the Bragg peak of the charged particle beam R spreads uniformly in the thickness direction (here, the Z-axis direction). The ridge filter 22 is arranged on the downstream side of the scatterer 5 and upstream of the monitor 4b on the base axis AX. A detailed description of the ridge filter 22 will be described later.

  The degrader 30 is disposed between the ridge filter 22 and the monitor 4b on the base axis AX. The degrader 30 adjusts the range of the charged particle beam R by reducing the energy of the charged particle beam R passing therethrough. The range may be adjusted by rough adjustment by a degrader (not shown) provided immediately after the accelerator 2 and fine adjustment by the degrader 30 in the irradiation unit 8. The degrader 30 is provided on the base axis AX and downstream of the charged electromagnets R from the scanning electromagnets 3 a and 3 b, the scatterer 5, and the ridge filter 22, so that the charged particle beam R reaches the maximum in the body of the patient 13. Adjust the depth. However, the position of the degrader 30 is not particularly limited. The degrader 30 is a plate-like member that extends in the X-axis direction and the Y-axis direction.

  A multi-leaf collimator (hereinafter referred to as “MLC”) 24 shapes the shape (planar shape) of the charged particle beam R in a plane direction perpendicular to the irradiation direction and includes a plurality of comb teeth. It has line parts 24a and 24b. The shielding portions 24a and 24b are disposed so as to face each other, and an opening 24c is formed between the shielding portions 24a and 24b. The MLC 24 cuts the charged particle beam R into an outline corresponding to the shape of the opening 24c by passing the charged particle beam R through the opening 24c.

  Further, the MLC 24 can change the position and shape of the opening 24c by moving the shielding portions 24a and 24b back and forth in a direction orthogonal to the Z-axis direction. Further, the MLC 24 is guided along the irradiation direction by the linear guide 28 and is movable along the Z-axis direction. The MLC 24 is disposed on the downstream side of the monitor 4b.

  The bolus 26 shapes the three-dimensional shape of the portion where the charged particle beam R reaches the maximum depth to match the shape of the maximum depth portion of the tumor 14. The shape of the bolus 26 is calculated based on, for example, the outline of the tumor 14 and the electron density of the surrounding tissue obtained from the X-ray CT data. The bolus 26 is disposed on the downstream side of the MLC 24 on the base axis AX. The patient collimator 27 finally shapes the planar shape of the charged particle beam R in accordance with the planar shape of the tumor 14. The patient collimator 27 is disposed on the downstream side of the bolus 26 on the base axis AX, and may be used in place of the MLC 24, or both the MLC 24 and the patient collimator 27 may be used. The bolus 26 and the patient collimator 27 are provided at the distal end 8 a of the irradiation unit 8.

  The control device 7 is constituted by, for example, a CPU, a ROM, a RAM, and the like. Based on the monitoring information output from the monitors 4a and 4b, the control device 7 performs the operations of the accelerator 2, the scanning electromagnets 3a and 3b, the scatterer 5, the ridge filter 22, the degrader 30, and the MLC 24 as necessary. Control.

  When the charged particle beam R is irradiated by the wobbler method (broad beam method) with the charged particle beam therapy system 1 shown in FIG. 3, the degrader 30 that can be adjusted to a predetermined range is set, and the shielding portion of the MLC 24 24a and 24b are advanced and retracted, and the opening part 24c is made into a predetermined shape.

  Subsequently, a charged particle beam R is emitted from the accelerator 2. The emitted charged particle beam R is scanned in a circle by the scanning electromagnets 3 a and 3 b and diffused by the scatterer 5. Adjusted. Thereby, the charged particle beam R is irradiated to the tumor 14 in the uniform irradiation range along the shape of the tumor 14.

  In FIG. 3, the charged particle beam therapy system 1 by the wobbler method is illustrated, but the wobbler method and other irradiation methods (for example, the scanning method or the layered body method) are switched by switching the setting / retraction of necessary components. ) Can be switched. Moreover, since the ridge filter 22 according to the present embodiment can be used regardless of the irradiation method as long as an enlarged Bragg peak is generated, the ridge filter 22 may be used at the time of irradiation by a scanning method or a layered body method.

  Next, details of the configuration of the ridge filter 22 will be described with reference to FIGS. In the present embodiment, the X-axis direction is described as corresponding to the “width direction” in the claims, but any direction in the XY plane may correspond to the “width direction”. In the following description, “center in the X-axis direction (width direction)” indicates the position of the base axis AX. “Outside in the X-axis direction (width direction)” indicates a direction away from the base axis AX, and “inside in the X-axis direction (width direction)” indicates a direction approaching the base axis AX.

  The ridge filter 22 includes a plurality of fins 12 arranged in the X-axis direction (width direction) that is orthogonal to the irradiation direction of the charged particle beam R (the direction in which the base axis AX extends), and the base portion 11 that supports the fins 12. And have. As a material of the ridge filter 22, for example, aluminum, resin, or the like may be used.

  The fins 12 are members that extend in the Y-axis direction in a fixed shape and are arranged in parallel with each other at a predetermined interval in the X-axis direction. In the present embodiment, the fin 12 has a triangular shape in a cross-sectional view (here, viewed in the Y-axis direction). The base portion 11 is for fixing the plurality of fins 12. Moreover, the base part 11 may have a frame-like shape with an opening at the center when viewed from the irradiation direction (see FIG. 6), or may be solid without an opening. In the present embodiment, the base portion 11 has a hexagonal frame shape, but the shape is not particularly limited, and may be another polygonal shape or a circular shape. Both ends of the fin 12 in the Y-axis direction are fixed to the base portion 11. Further, the shape of the base portion 11 does not have to be a frame shape, and may be any shape as long as the function as the ridge filter 22 can be exhibited.

  In the present embodiment, the fins 12 are formed integrally with the base portion 11. Here, the state of being “integrally formed” means, for example, that a lump of material is machined and the boundary surface between the fin 12 and the base portion 11 does not exist, and both portions are It is a united state. In addition, as a processing method for integrally forming, a layered modeling using a 3D printer may be employed in addition to machining. In the present embodiment, all of the plurality of fins 12 are formed integrally with the base portion 11, but only some of the fins 12 may be formed integrally with the base portion 11. When some of the fins 12 and the base portion 11 are formed as separate bodies, the fins 12 formed as separate bodies are screwed to the base portion 11 and are connected to the grooves provided in the base portion 11. It is fixed by a fixing method such as fitting.

  As shown in FIG. 5A, fins 12A arranged at the center position in the width direction (or near the center position) (hereinafter, the fins 12 at the center position are referred to as fins 12A to be distinguished from other fins 12). Is arranged at a position where the charged particle beam R is irradiated along the base axis AX. Thereby, the axis CL of the fin 12A coincides with the base axis AX. Therefore, the cross section of the fin 12A has a line-symmetric shape with respect to the base axis AX. Here, the fins 12A are isosceles triangles. Here, when the angle formed by the base axis AX and the axis line CL is defined as “inclination angle θ”, the inclination angle of the fin 12A is 0 °.

  Here, among the fins 12, the charged particle beam R is incident on the fins 12 that are disposed at positions outside the X axis direction (that is, positions away from the base axis AX) while being inclined from the base axis AX. (See FIG. 5 (b)). This is because the charged particle beam R advances to the fin 12 at the outer position while being inclined with respect to the base axis AX by being scanned with the scanning electromagnet. Accordingly, the fins 12 arranged at the outer positions in the X-axis direction may be inclined in accordance with the inclination of the charged particle beam R. The fin 12 is inclined toward the center side in the X-axis direction. In the present embodiment, the fact that the fin 12 is inclined indicates that the axis line CL set with respect to the triangle of the fin 12 is inclined with respect to the base axis AX. Here, the inclination angle θ is larger than 0 °. However, in FIG. 5B, “θ” is attached to the angle formed by the straight line parallel to the base axis AX and the axis line CL. Thus, when the inclination angle θ is greater than 0 °, the cross-sectional shape of the fin 12 is asymmetric between the negative side and the positive side in the X-axis direction. Here, the cross section of the fin 12 is a triangle in which the side surface 12a on the X axis direction negative side is shorter than the side surface 12b on the X axis direction positive side.

  For example, as shown in the fin 12 on the right side of FIG. 5A, the charged particle beam R (shown here as VR because it is an irradiation of a virtual charged particle beam R) is inclined with respect to the base axis AX. If the fin 12 is not inclined, the distance that the charged particle beam VR passes through the fin 12 is shortened, and the attenuation may be smaller than a desired value. Alternatively, depending on the incident position, the distance that the charged particle beam VR passes through the fin 12 may be longer than when the fin 12 is not inclined, and the attenuation may be larger than a desired value. Further, the charged particle beam VR may pass through the plurality of fins 12, and the attenuation may be larger than a desired value. From the above, when the fin 12 is not inclined according to the incident angle of the charged particle beam R, a desired enlarged Bragg peak may not be obtained. On the other hand, as shown in FIG. 5B, since the fin 12 is inclined in accordance with the inclination of the charged particle beam R, the distance that the charged particle beam R passes through the fin 12 can be made closer to a desired value. The enlarged Bragg peak can be brought close to a desired characteristic.

  The axis CL of the fin 12 is a line passing through the center of the fin 12. For example, the axis line CL is directed from the corner portion P on the inner side in the X-axis direction of the fin 12 (here, the corner portion between the X-axis direction negative side surface 12a and the bottom surface 12c of the fin 12) toward the outer side surface 12b. An isosceles triangle is created by setting a virtual base BL. The center line of the isosceles triangle created in this way may be set as the axis line CL. Alternatively, a line connecting the center of the bottom surface 12c in the X-axis direction and the vertex TP may be set as the axis line CL.

  In addition, the conditions for inclining the fins 12 are not particularly limited, but the fins 12 may be inclined in a state where predetermined parameters are constant. For example, the area ratio between the fin 12 to be inclined and the fin 12A at the center position may be constant. Further, the height H of the fin 12 to be inclined (the dimension in the Z-axis direction between the vertex TP of the fin 12 and the surface of the base portion 11) and the height H of the fin 12A at the center position may be constant. Alternatively, the length L of the axis CL passing through the fin 12 to be inclined and the length L (equal to the height H) of the axis CL passing through the fin 12A at the center position may be constant.

  Among the plurality of fins 12, at least some of the fins 12 may be inclined. The incident angle of the charged particle beam R is larger on the outer side in the X-axis direction. Therefore, among the plurality of fins 12, at least the outermost fin 12 in the X-axis direction (width direction) may be inclined toward the center side in the X-axis direction.

  Further, the fin 12 may have a larger inclination angle θ as it is located on the outer side in the X-axis direction (width direction). At this time, the inclination angle θ of all the fins 12 in the ridge filter 22 may be changed one by one in accordance with the position in the X-axis direction. However, the inclination angle θ may be changed by a plurality. For example, the inclination angle of the plurality of fins 12 near the center may be 0 °, and the plurality of fins 12 adjacent to the group may be inclined at the same inclination angle θ.

  When the inclination angle θ of the fin 12 changes one by one, the fin 12 may be inclined such that the respective axis lines CL intersect at a preset point. In the example shown in FIG. 4, the axis line CL of each fin 12 intersects at a point SP set in the scanning electromagnet 3a (which is a starting point of scanning). However, the axis CL of all the fins 12 may intersect at the point SP, or the axis CL of some of the fins 12 may intersect at the point SP.

  Next, operations and effects of the charged particle beam therapy apparatus 1 and the ridge filter 22 according to the present embodiment will be described.

  In the charged particle beam therapy system 1 according to the present embodiment, the ridge filter 22 includes a plurality of fins 12 arranged in the X-axis direction (width direction) that is orthogonal to the Z-axis direction (charged particle beam irradiation direction). And a base portion 11 that supports the fins 12. In such a configuration, the fin 12 is formed integrally with the base portion 11. Therefore, the positional accuracy between the fin 12 and the base part 11 can be improved. The charged particle beam R can be passed through a desired position of the fin 12 by improving the positional accuracy between the fin 12 and the base portion 11. Thereby, an expansion Bragg peak can be brought close to a desired characteristic.

  Further, among the plurality of fins 12, at least the fin 12 positioned on the outermost side in the X-axis direction may be inclined toward the center side in the X-axis direction. The charged particle beam R is incident on the outer fin 12 in the X-axis direction in a state inclined from the base axis AX. Accordingly, corresponding to this, at least the outermost fin 12 positioned in the X-axis direction is inclined toward the center side in the X-axis direction, so that the distance that the charged particle beam R passes through the fin 12 is set to a desired value. It can be close to the value. Thereby, an expansion Bragg peak can be brought close to a desired characteristic.

  Further, the inclination angle θ of the fin 12 may be larger as it is located on the outer side in the X-axis direction. Since the inclination of the charged particle beam R from the base axis AX increases toward the outside in the X-axis direction, the inclination angle θ of the fin 12 can correspond to the inclination of the charged particle beam R.

  Moreover, when the axis line CL which passes through the center in each X-axis direction is set with respect to each fin 12, the fin 12 may incline so that each axis line CL may intersect at the preset point SP. With such a configuration, the inclination angle θ of each fin 12 can correspond to the inclination of the charged particle beam R.

  The ridge filter 22 according to the embodiment is a ridge filter 22 for the charged particle beam therapy system 1 that generates an enlarged Bragg peak of the charged particle beam R. The ridge filter 22 includes a plurality of fins 12 arranged in the X-axis direction and a base portion 11 that supports the fins 12. The fins 12 are formed integrally with the base portion 11.

  According to the ridge filter 22 according to the present embodiment, it is possible to obtain the same functions and effects as those of the charged particle beam therapy system 1 described above.

  The present invention is not limited to the embodiment described above.

  For example, in the above-described embodiment, each fin is made of the same material, but some of the fins may be made of different materials. Of the plurality of fins 12 shown in FIG. 7, at least the outermost fin 15 located in the X-axis direction is lower than the height H of the fin 12 located on the center side. Further, the density of the fins 15 located on the outer side is higher than that of the fins 12 located on the center side. Further, the fin 12 located on the center side is formed integrally with the base portion 11. As a material used for such a fin 15, iron, brass, or the like may be employed.

  With such a configuration, the attenuation amount can be adjusted according to the inclination of the charged particle beam R by adjusting the height and density of the fins 15 on the outer side in the X-axis direction where the inclination of the charged particle beam R becomes large. it can. On the other hand, on the inner side in the X-axis direction in which the inclination of the charged particle beam R becomes small, the positional accuracy of the fin 12 can be improved by forming the fin 12 integrally with the base portion.

  Further, the shape of the fins may not be a perfect triangle, and may be, for example, a shape with rounded vertices or a shape with gently curved side surfaces.

  DESCRIPTION OF SYMBOLS 1 ... Charged particle beam therapy apparatus, 2 ... Accelerator, 8 ... Irradiation part, 11 ... Base part, 12, 15 ... Fin, 22 ... Ridge filter, 40 ... Transport line.

Claims (6)

An accelerator that accelerates charged particles and emits charged particle beams;
An irradiating unit that irradiates an object to be irradiated with the charged particle beam, having a ridge filter that generates an enlarged Bragg peak of the charged particle beam;
A transport line for transporting the charged particle beam emitted from the accelerator to the irradiation unit, and
The ridge filter is
A plurality of fins arranged in a width direction that is a direction orthogonal to the irradiation direction of the charged particle beam;
A base portion for supporting the fin,
The charged particle beam therapy apparatus, wherein the fin is formed integrally with the base portion.   The charged particle beam therapy system according to claim 1, wherein at least an outermost fin in the width direction among the plurality of fins is inclined toward a center side in the width direction.   The charged particle beam therapy system according to claim 2, wherein the fin has a larger inclination angle as it is located on the outer side in the width direction.   When the axis line which passes through the center is set with respect to each said fin, the said fin is inclined so that each said axis line may cross at a preset point. The charged particle beam therapy apparatus according to item. Among the plurality of fins, at least the fin located on the outermost side in the width direction is lower than the height of the fin located on the center side,
The density of the fins located on the outside is higher than the fins located on the center side,
The charged particle beam therapy apparatus according to any one of claims 1 to 4, wherein the fin located on the center side is formed integrally with the base portion. A ridge filter for a charged particle beam therapy apparatus that generates an expanded Bragg peak of a charged particle beam,
A plurality of fins arranged in a width direction that is a direction orthogonal to the irradiation direction of the charged particle beam;
A base portion for supporting the fin,
The fin is a ridge filter formed integrally with the base portion.

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