JP2013013613A - Charged particle beam irradiation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attempt the miniaturization of a charged particle irradiation device by arranging a transport line in the rear side of an irradiation chamber in the charged particle beam irradiation device that includes a detector that detects the gamma rays generated in a body to be irradiated.SOLUTION: The charged particle beam irradiation device 10 that includes an irradiation chamber 21 having a charged particle beam irradiation part 11 rotatable around the irradiated body to which a charged particle beam is irradiated, includes: a detector 91 detecting gamma rays generated in the irradiated body; and a support mechanism 92 that supports the detector 91 and can integrally rotate with the charged particle beam irradiation part 11, and in which the detector 91 is able to move in the irradiation chamber 21, wherein the support mechanism 92 is configured such that the detector is made to move in the diameter direction in the rotation track of the charged particle beam irradiation part 11.

Description

  The present invention relates to a charged particle beam irradiation apparatus that irradiates a charged particle beam.

  A facility for treating cancer by irradiating a patient with a charged particle beam such as a proton beam is known. This kind of equipment is a rotating gantry (rotation) equipped with a cyclotron (accelerator) that accelerates charged particles and emits charged particle beams, and a rotatable irradiation unit that irradiates a patient with charged particle beams from any direction. Body) and a transport line for transporting charged particle beams emitted from the cyclotron to the irradiation section.

  In addition, the charged particle beam irradiation apparatus described in Patent Document 1 below is disposed on both sides of the irradiated object to be irradiated with the charged particle beam, and detects a pair of annihilation gamma rays generated by the irradiated object. A detection unit is provided. In the rotating gantry of the charged particle beam irradiation apparatus, an irradiation chamber is formed in which an irradiated object is arranged and charged particle beam irradiation is performed. The irradiation chamber includes a back panel (back wall) that partitions the back side.

  In the charged particle beam irradiation apparatus described in Patent Document 1 below, the pair of detection units can be moved in the direction in which the rotation center axis of the rotating gantry extends and can be stored on the back side of the back panel of the irradiation chamber. It is made into the composition.

JP 2008-173297 A

  Generally, a charged particle beam irradiation apparatus is installed in a building having a radiation shielding wall. There is a need to reduce the length of the rotating gantry in the rotation axis direction and to reduce the size of the charged particle beam irradiation device and the building by improving the arrangement of the transportation line for transporting the charged particle beam to the irradiation part. Yes. Thus, the construction cost can be reduced by downsizing the charged particle irradiation apparatus and the building.

  However, in the charged particle beam irradiation apparatus described in Patent Document 1, since the detection unit is moved in the rotation axis direction of the rotating gantry and accommodated on the back side of the back panel, it is transported close to the back panel of the irradiation chamber. The line could not be arranged, and it was difficult to improve the arrangement of the transportation line and reduce the size of the apparatus.

  An object of the present invention is to solve the above problems, and in a charged particle beam irradiation apparatus equipped with a detector for detecting gamma rays generated in an irradiated body, a transport line is arranged on the back side of the irradiation chamber. An object of the present invention is to reduce the size of a charged particle irradiation apparatus.

  The present invention detects a gamma ray generated in an irradiated body in a charged particle beam irradiation apparatus having an irradiation chamber having a charged particle beam irradiation section that can rotate around an irradiated body irradiated with the charged particle beam. A detection unit and a support mechanism that can rotate and move integrally with the charged particle beam irradiation unit while supporting the detection unit, and that can move the detection unit in the irradiation chamber. The detection unit can be retracted in a radial direction on the rotation path of the irradiation unit.

  A charged particle beam irradiation apparatus according to the present invention includes a charged particle beam irradiation unit that can rotate around an irradiated object, and a detection unit that detects gamma rays generated from the irradiated object has an irradiation chamber in which the charged particle beam is irradiated In FIG. 3, the charged particle beam irradiation unit is configured to be capable of moving back and forth in the radial direction of the rotating orbit. Thereby, when a gamma ray is not detected, the detection unit can be retracted radially outward. When the gamma ray is not detected (when not in use), the detection unit that has been retracted is moved to the vicinity of the irradiated object (near the center of rotation) when starting to be used, and after use, it is retracted radially outward again. Can be made. Thereby, it is not necessary to adopt a conventional configuration in which the detection unit is retracted and accommodated along the rotation center axis on the back side of the irradiation chamber. Therefore, it is possible to secure a space for arranging the beam transport line on the back side closest to the irradiated body. As a result, by using the space on the back side closest to the irradiated object, the degree of freedom of arrangement of the beam transport line is improved, and interference between the gamma ray detector and the beam transport line is avoided, and the charged particle beam irradiation apparatus Miniaturization can be achieved.

  Further, the support mechanism may retract the detection unit that does not detect gamma rays to the side of the charged particle beam irradiation unit. Thereby, the detection unit can be retracted to the side of the charged particle beam irradiation unit.

  In addition, a PET camera is provided as a pair of detection units that detect annihilation gamma rays generated in the irradiated body upon irradiation with the charged particle beam, and the pair of PET cameras are disposed on both sides of the irradiated body, The pair of PET cameras may be movable in the radial direction by one drive source that applies a driving force for moving the PET camera. Thus, by driving a pair of PET cameras by one drive source, the apparatus configuration can be simplified.

  The support mechanism includes a support arm that swingably supports the detection unit around a predetermined axis extending in the width direction of the charged particle beam irradiation unit, and a detection unit in the width direction of the charged particle beam irradiation unit. It is good also as a structure provided with the drive part made to approach or space apart with respect to the said to-be-irradiated body. As described above, the movement range of the support mechanism can be suppressed by swinging the support arm with the predetermined axis extending in the width direction of the charged particle beam irradiation unit as a base point. That is, it is possible to support the detection unit movably by arranging the support mechanism in the irradiation chamber while saving space. For example, in the case of a configuration in which the support mechanism moves linearly along the rotation center axis direction of the rotating gantry as in the prior art, the support mechanism protrudes outside the irradiation chamber, but in the support mechanism according to the present invention, Since the support arm swings, it can be installed so that the support mechanism does not protrude outside the irradiation chamber. The “width direction of the charged particle beam irradiation unit” is a horizontal direction when the irradiation direction of the charged particle beam is used as a reference when viewed from the rotation axis direction of the charged particle beam irradiation unit.

  The support mechanism includes a support arm that swingably supports the detection unit around a predetermined axis extending in the width direction of the charged particle beam irradiation unit, and a detection unit in the width direction of the charged particle beam irradiation unit. It is good also as a structure provided with the drive part made to approach or space apart to a to-be-irradiated body. As described above, the detection unit may be advanced and retracted in the radial direction by swinging the support arm around a predetermined axis extending in the width direction of the charged particle beam irradiation unit. Moreover, since the drive part which makes a detection part approach or separate with respect to a to-be-irradiated body is provided, a detection part can be made to approach to a to-be-irradiated body, and a gamma ray can be detected.

  Further, the support mechanism may include a mechanism that converts linear motion into rotational motion, and the support arm may be configured to swing by being applied with the driving force transmitted by the mechanism. As a result, it is not necessary to apply a driving force by a member that reciprocates over a relatively long distance as before, so that the driving mechanism for swinging the support arm can be made compact.

  Further, the support mechanism may be configured to include a trunnion mechanism that is supported by the charged particle beam irradiation unit and swings the support arm with respect to the charged particle beam irradiation unit. Thus, the support arm can be swung with respect to the charged particle beam irradiation unit using the trunnion mechanism supported by the charged particle beam irradiation unit.

  In addition, the support mechanism preferably includes a drive mechanism that causes the PET camera, which is a pair of detection units, to approach or separate from the irradiated object in the width direction of the charged particle beam irradiation unit with one drive source. Thereby, the detection accuracy of gamma rays can be improved by bringing the pair of PET cameras close to the irradiated object.

  According to the present invention, in a charged particle beam irradiation apparatus including a detector that detects gamma rays generated in an irradiated body, the detection unit is retracted to the outside in the radial direction of the rotating orbit of the charged particle beam irradiation unit. Therefore, a space for arranging the beam transport line can be secured on the back side of the irradiation chamber. Therefore, it is possible to reduce the size of the charged particle beam irradiation apparatus including the gamma ray detector.

It is a schematic block diagram of the proton beam treatment system provided with the proton beam treatment apparatus which concerns on embodiment of this invention. It is a front view of the proton beam therapy apparatus which concerns on embodiment of this invention. 1 is a perspective view of a proton beam therapy apparatus according to an embodiment of the present invention. It is the schematic sectional drawing which cut the rotation gantry of the proton beam therapy equipment concerning the embodiment of the present invention in the horizontal direction along the axis of rotation. It is a front view of the beam irradiation nozzle of the proton beam therapy apparatus which concerns on embodiment of this invention. It is a side view of the beam irradiation nozzle of the proton beam therapy apparatus which concerns on embodiment of this invention. It is a perspective view which shows the beam transport line and beam irradiation nozzle which were attached to the rotation gantry. It is a figure which shows each element arrange | positioned in an irradiation nozzle. It is a side view which shows a pair of PET camera and support arm which are arrange | positioned to the side of a to-be-irradiated body. It is a perspective view which shows a pair of PET camera and support arm which are arrange | positioned at the side of a to-be-irradiated body. It is a flowchart which shows the process of the proton beam irradiation method which concerns on embodiment of this invention. It is a side view which shows the PET camera which concerns on other embodiment.

  Hereinafter, a preferred embodiment of a charged particle beam irradiation apparatus according to the present invention will be described with reference to the drawings. In the present embodiment, a proton beam therapy system including a proton beam therapy apparatus (charged particle beam irradiation apparatus) will be described. The proton beam treatment apparatus is applied to cancer treatment, for example, and is an apparatus that irradiates a tumor (irradiated body) in a patient's body with a proton beam (charged particle beam).

  As shown in FIG. 1, a proton beam treatment system 1 is transported by a cyclotron (particle accelerator) 2 that generates a proton beam, a beam transport line 3 that transports a proton beam emitted from the cyclotron 2, and a beam transport line 3. A proton beam treatment apparatus 10 that irradiates a subject with a proton beam is provided. Each device of the proton beam treatment system 1 is accommodated in the building 5.

  The proton beam accelerated by the cyclotron 2 has its path changed along the beam transport line 3 and is transported to the proton beam treatment apparatus 10. The beam transport line 3 is provided with a deflection magnet for deflecting the proton beam, a quadrupole electromagnet for performing beam shaping, and the like.

  As shown in FIGS. 2 to 5, the proton beam treatment apparatus 10 includes a beam introduction line 31 that is introduced by the beam transport line 3 and transports the proton beam to the beam irradiation nozzle 11, and a proton beam transported by the beam introduction line 31. A beam irradiation nozzle 11 that irradiates the irradiated object (see patient 61, see FIGS. 2 and 3), and a rotating gantry 12 that supports the beam introduction line 31 and the beam irradiation nozzle 11 and is rotatable about a predetermined rotation axis P. It has.

  As shown in FIG. 4, the rotating gantry 12 includes a cylindrical main body portion 13, a cone portion 14, and a second cylindrical portion 15 that are arranged in the rotation axis P direction. The cylindrical main body part 13, the cone part 14 and the second cylindrical part 15 are arranged on the same axis (rotation axis P) and connected to each other. The side on which the cylindrical body 13 is disposed is the front side of the rotating gantry 12, and the side on which the second cylindrical portion 15 is disposed is the back side of the rotating gantry 12.

The cylindrical main body portion 13 and the second cylindrical portion 15 are thin-walled cylindrical bodies, and are configured to be lightweight while maintaining rigidity. The second cylindrical portion 15 has a smaller diameter than the cylindrical main body portion 13, and the cone portion 14 is formed in a conical shape so as to connect the cylindrical main body portion 13 and the second cylindrical portion 15. The cone part 14 is formed so that the inner diameter becomes smaller from the front side toward the back side. The length L _{2 of} the rotating gantry 12 in the direction of the rotation axis P (the length from the front side end of the cylindrical main body 13 to the back side end of the second cylindrical portion 15) is, for example, about 4.6 m. It is said that.

  At both ends of the cylindrical main body 13 in the direction of the rotation axis P, ring portions 13a and 13b, which are hollow members having a rectangular cross-sectional shape, for example, are provided. The ring portions 13a and 13b may be solid members. As shown in FIG. 2, the cylindrical main body 13 is rotatably supported by a roller device 20 disposed below the cylindrical main body 13. The roller device 20 functions as a driving device for rotating the rotating gantry 12.

  The front side of the cylindrical main body 13 is open, and it is possible to enter the cylindrical main body 13. On the other hand, a back panel (partition wall) 16 is provided on the back side of the cylindrical main body 13. An area surrounded by the cylindrical main body 13 and the back panel 16 is configured as an irradiation chamber 21. The bed 22 can be moved by a robot arm 23. During normal times when treatment is not performed, the bed 22 is disposed outside the rotating gantry 12 (irradiation chamber 21), and the bed 22 is disposed within the irradiation chamber 21 when treatment is performed. In addition, illustration of the bed 22 is abbreviate | omitted in FIGS.

  The irradiation nozzle (proton beam irradiation unit) 11 is fixed to the inner surface side of the cylindrical main body 13 and rotates around the rotation axis P together with the cylindrical main body 13. The irradiation nozzle 11 moves along with the rotation of the cylindrical main body 13, and the emission direction of the proton beam is changed. The irradiation nozzle 11 is a part that emits a proton beam to the irradiated object in the irradiation chamber 21. The irradiation nozzle 11 has a housing 11a in which a beam line continuous to the beam introduction line 31 is formed. Further, various components (described later) for beam adjustment are arranged in the housing 11a.

  A beam introduction line 31 that is a beam transport line of the proton beam treatment apparatus 10 is connected to the beam transport line 3 that transports the proton beam emitted from the cyclotron 2, and the proton beam transported by the beam transport line 3 is irradiated with the proton nozzle 11. To introduce.

  FIG. 7 is a perspective view showing a beam introduction line and a beam irradiation nozzle attached to the rotating gantry. As shown in FIG. 7, the beam introduction line 31 is provided downstream of the first vent portion 32 and the first vent portion 32 that deflects the proton beam traveling in the direction of the rotation axis P of the rotating gantry 12. Are inclined with respect to the direction of the rotation axis P, the second bent portion 34 is provided downstream of the inclination portion 33 and deflects the proton beam B in the direction perpendicular to the rotation axis P, and the second A third vent part 35 provided downstream of the vent part 34 for turning the traveling direction of the proton beam B in the rotational direction of the rotation axis P, and provided downstream of the third vent part 35, the irradiation nozzle 11 emits the proton beam B. A linear portion 36 that travels upward (in the state shown in FIG. 2), and a fourth vent portion 37 that is provided downstream of the linear portion 36 and curves the proton beam B toward the axial center (rotation axis P side). , 4th vent Provided downstream of 37 comprises a straight portion 38 to advance the proton beam B to the irradiation nozzle 11, a.

  The first vent portion 32 is configured by a 45 degree deflection electromagnet that curves the proton beam B and deflects the traveling direction by 45 degrees. The inclined portion 33 is configured to include optical elements such as a quadrupole electromagnet 41, a steering electromagnet 42, and a profile monitor 43. The quadrupole electromagnet 41 has a function of adjusting the size at the irradiation position of the proton beam B and the optical focal position. The steering electromagnet 42 has a function of translating the beam axis. The profile monitor 43 has a function of detecting the shape and position of the passing proton beam B.

  The second vent portion 34 is configured by a 45 degree deflection electromagnet that curves the proton beam B and deflects the traveling direction by 45 degrees. Further, a profile monitor 43 is disposed between the second vent part 34 and the third vent part 35. The third vent portion 35 is constituted by a 135-degree deflecting electromagnet that curves the proton beam B and deflects the traveling direction by 135 degrees.

  The straight portion 36 includes a quadrupole electromagnet 41, a steering electromagnet 42, and a profile monitor 43. The fourth vent portion 37 is composed of a 135-degree deflecting electromagnet that curves the proton beam B and deflects the traveling direction by 135 degrees. The straight portion 38 includes a quadrupole electromagnet 41 and a profile monitor 43.

  In the proton beam therapy apparatus 10 of this embodiment, a part of the beam introduction line 31 attached to the rotating gantry 12 is in the cylindrical body (cylindrical main body portion 13, cone portion 14, second cylindrical portion 15) of the rotating gantry 12. Is placed through. The proton beam B transported by the beam transport line 3 is introduced into the inside from the back side of the second cylindrical portion 15, passes through the second cylindrical portion 15, the cone portion 14, and the cylindrical main body portion 13, It penetrates through the cylindrical main body 13 and is led out of the cylindrical main body 13.

  As shown in FIG. 4, the beam introduction line 31 is disposed so as to penetrate the back panel 16 and enter the cylindrical main body 13 and pass through the irradiation chamber 21. Further, the irradiation chamber 21 may be configured to include a shielding material (for example, polyethylene, lead, stainless steel, etc.) that shields transmission of radiation such as a neutron beam around the beam introduction line 31.

  Further, on the outer peripheral surface of the cylindrical main body 13, a gantry 17 is provided for supporting the beam introduction line 31 projecting outward from the cylindrical main body 13. The beam introduction line 31 protruding outward from the cylindrical body 13 is referred to as a beam introduction line extension 31a. The 3rd vent part 35, the linear part 36, and the 4th vent part 37 are contained in the introduction line overhang | projection part 31a. The gantry 17 is fixed to the outer surface of the cylindrical main body 13 and projects outward in the radial direction. The gantry 17 supports the beam introduction line projecting portion 31a from the inside in the radial direction. Thereby, a load of an electromagnet (quadrupole electromagnet 41, 135 degree deflection electromagnet) or the like can be received by the cylindrical main body 13.

  A counterweight 18 is provided on the outer peripheral surface of the cylindrical main body 13 so as to be opposed to the rotation axis P. By installing the counterweight 18, a weight balance with respect to the third vent portion 35, the straight portion 36, the fourth vent portion 37, and the mount 17 disposed on the outer surface of the cylindrical main body portion 13 is secured.

  The rotating gantry 12 is rotationally driven by a motor (not shown), and the rotation is stopped by a brake device (not shown).

  Next, the irradiation nozzle 11 will be described. The proton beam therapy apparatus 10 includes an irradiation nozzle 11 that is attached to a rotating gantry 12 and is rotatable around a bed 22.

  FIG. 8 is a diagram showing each element arranged in the irradiation nozzle. As shown in FIG. 8, the irradiation nozzle 11 is arranged in order in the proton beam irradiation direction A, and the scatterer 71 for sequentially passing the proton beam and shaping the beam, a ridge filter unit 72, a fine degrader 73, a block collimator. 74, a bolus 75, a multi-leaf collimator 76, and an irradiation control unit 77 for controlling the driving of each part of the apparatus.

  A proton beam generated by the cyclotron 2 is sent to the irradiation nozzle 11 through beam transport lines 3 and 31. Then, the narrow proton beam that has been sent is passed through a scatterer (beam expanding portion) 71 made of lead having a thickness of, for example, several millimeters, so that the beam spreads in a direction perpendicular to the irradiation direction A, and a wide beam is obtained. Expanding.

  The proton beam from the scatterer 71 has a ridge filter section (peak adjustment filter) for providing a distribution in the energy depth of the proton beam corresponding to the thickness of the tumor 62 in the patient 61 (length in the irradiation direction A). Part) 72. The ridge filter portion 72 has a plurality of filters 72a in which metal rods whose thickness changes stepwise are arranged in a bowl shape, and the plurality of filters 72a have different protons depending on the shape of the metal rods. An extended Bragg peak (hereinafter referred to as “SOBP”) of the line is formed. The ridge filter unit 72 is driven by the control of the irradiation control unit 77, and has a mechanism for inserting a filter appropriately selected from the plurality of filters 72a into the proton beam passage position. With this configuration, the ridge filter unit 72 can selectively change the filter 72a through which the proton beam passes, and can adjust the SOBP peak width of the proton beam.

  The proton beam that has passed through the ridge filter unit 72 adjusts the energy of the proton beam according to the depth of the tumor 62 in the patient 61 to be treated, and a fine degrader (beam) for adjusting the maximum reachable depth. It is incident on an energy adjusting unit 73. The fine degrader 73 is composed of, for example, two wedge-shaped opposing acrylic blocks 73a and 73b. By adjusting the overlapping of the blocks 73a and 73b under the control of the irradiation control unit 77, the proton beam is changed. The thickness of the passing part can be continuously changed. The proton beam loses energy in accordance with the thickness of the substance that has passed through, and the depth that the proton beam reaches within the patient 61 changes. Therefore, by adjusting this fine degrader 73, the position of the SOBP of the proton beam is changed to the tumor in the patient 61. It is possible to match the position in the depth direction 62 (irradiation direction A).

  The proton beam that has passed through the fine degrader 73 is incident on a block collimator 74 for roughly shaping the planar shape (shape viewed from the irradiation direction A) of the proton beam. In addition to the multi-leaf collimator 76 described later, the reason why the block collimator 74 performs shaping is to prevent secondary radiation from being generated by the block collimator 74 near the patient.

  The proton beam that has passed through the block collimator 74 is input to a bolus (compensation filter) 75 that is, for example, a resin-made irregular filter, and correction is performed regarding the cross-sectional shape of the maximum depth of the tumor 62 and the tissue non-uniformity. . The shape of the bolus 75 is calculated based on the outline of the tumor 62 and the electron density of the surrounding tissue obtained from, for example, X-ray CT data. By using such a bolus 75, the three-dimensional shape of the farthest portion of the proton beam (the portion with the maximum reachable depth) is shaped in accordance with the shape of the maximum depth portion of the tumor 62, so dose concentration with respect to the tumor 62 The sex can be further enhanced.

  The proton beam that has passed through the bolus 75 is incident on a multi-leaf collimator (shape variable collimator) 76. The multi-leaf collimator 76 is configured by arranging two shielding portions 76a and 76b made of brass and having a large number of comb teeth having a width of several millimeters so that the tips of the comb teeth are abutted on the center. Then, under the control of the irradiation control unit 77, the shielding units 76a and 76b advance and retract each of the numerous comb teeth in the longitudinal direction, so that the multi-leaf collimator 76 has the position of the opening 76c through which the proton beam passes and The shape can be changed.

  The proton beam that has passed through the multi-leaf collimator 76 is cut to a contour corresponding to the shape of the opening 76c. Therefore, the multi-leaf collimator 76 can change the shape of the opening 76c to change the desired plane position of the incident proton beam. And a planar shape can be cut out. The proton beam thus cut out in a desired planar shape at a desired planar position is irradiated to the patient 61 as a therapeutic proton beam. Then, by changing the planar position and planar shape of the opening 76c of the multi-leaf collimator 76 and moving the irradiation field position sequentially in the horizontal direction (direction orthogonal to the irradiation direction A), the irradiation is repeated over the entire tumor 62. Irradiate a proton beam.

  Further, the irradiation nozzle 11 includes a dose monitor 78 as means for monitoring the irradiation dose irradiated to the irradiation field. The dose monitor 78 is provided between the fine degrader 73 and the block collimator 74 and detects the dose of the proton beam that passes therethrough. The dose monitor 78 transmits the detected dose as the monitor signal s1 to the irradiation control unit 77, and the irradiation control unit 77 can recognize the irradiation dose irradiated to the irradiation field based on the monitor signal s1.

  In addition, as shown in FIG. 6, the proton therapy apparatus 10 is provided with an X-ray imaging apparatus (X-ray fluoroscopic image acquisition means) 80 that acquires an X-ray fluoroscopic image of the patient 61. The X-ray imaging apparatus 80 includes an X-ray generator 81 and an X-ray detector 82 that detects X-rays transmitted through the patient 61. These X-ray generator 81 and X-ray detector 82 are fixed to the rotating gantry 12 and are rotatable around the patient 61. In the present embodiment, two X-ray generators 81 are provided, and these X-ray generators 81 are arranged at positions where the rotation angles about the rotation axis P are different by 90 degrees. Further, an X-ray detector 82 is disposed at a position facing the X-ray generator 81 with the rotation axis P interposed therebetween. The X-ray imaging apparatus 80 can create an X-ray fluoroscopic image of the patient 61 based on the data detected by the X-ray detector 82, detect bones and metal markers, and measure the position of the patient 61. .

  Here, the proton beam treatment apparatus 10 includes a PET apparatus 90 having a pair of PET cameras (detectors) 91 attached to the rotating gantry 12 and capable of rotating around the bed 22. That is, the PET camera 91 can rotate about the rotation axis P integrally with the irradiation nozzle 11 attached to the rotating gantry 12. In addition to the PET camera 91, the PET device 90 includes an image processing unit, a recording unit, a display unit, and the like (not shown). The image processing unit performs image processing based on the image information acquired by the PET camera 91 to generate a PET image. The recording unit records the generated PET image and the like. The generated PET image is displayed by the display unit.

The PET cameras 91 are arranged on both sides of the patient 61 on the bed 22 and detect annihilation γ rays. Specifically, the patient 61 is administered (injected) with a radiopharmaceutical (for example, ¹¹ C methionine) that accumulates in the tumor 62, and the PET camera 91 performs annihilation gamma rays generated from the tumor 62 (position where the radiopharmaceutical reaches). Is detected. The PET apparatus 90 functions as an irradiation target position detection unit that detects the position of the tumor 62 based on the detection result of the annihilation γ rays by the PET camera 91.

  The PET camera 91 can detect annihilation γ rays (gamma rays) from positron emission nuclei generated by the nuclear reaction between the incident proton nuclei of the proton beam irradiated to the patient 61 and the nuclei in the tumor 62. . Further, the PET apparatus 90 functions as a proton beam (charged particle beam) arrival position detection means for detecting the arrival position of the proton beam actually irradiated on the basis of the detection result of the annihilation gamma ray by the PET camera 91 in the body of the patient 61. To do. That is, the PET apparatus 90 measures annihilation gamma rays from the positron emitting nuclides generated in the body by the mutual nuclear reaction between the incident proton nuclei of the proton beam used in the treatment and the nuclei in the body of the patient 61, and generates By measuring the intensity distribution, the actual proton beam arrival position in the patient 61 can be detected.

  In addition, the proton beam therapy apparatus 10 includes a support mechanism 92 that allows the PET camera 91 to move in the irradiation direction A of the proton beam in the irradiation chamber 21. Note that a direction intersecting (orthogonal) with the direction in which the rotation axis P extends (first direction) and the proton beam irradiation direction A (second direction) is the C direction (third direction, charged particle beam irradiation unit). In the width direction). The support mechanism 92 moves (advances and retreats) the PET camera 91 in the proton beam irradiation direction A by swinging the PET camera 91 with respect to the irradiation nozzle 11. Specifically, the PET camera 91 is moved in parallel with the irradiation direction A in front view (viewed from the direction of the rotation axis P). The support mechanism 92 is not limited to one that moves the PET camera 91 in parallel with the irradiation direction A in front view. For example, the moving direction of the PET camera 91 may be inclined with respect to the irradiation direction A. Moreover, it is not limited to what moves linearly, A moving direction may be curvilinear.

  9 and 10 are diagrams showing a pair of PET cameras and a support mechanism. As shown in FIG. 9, the support mechanism 92 includes a bracket (fixed portion) 93 fixed to the irradiation nozzle 11, a trunnion mechanism portion 94 supported by the bracket 93 for swinging the PET camera 91, and a trunnion mechanism portion. 94, connected to the bracket 93 through 94, and a drive unit (third direction drive unit) 95 for moving the PET camera 91 in the direction C shown in the figure, and supports the PET camera 91 and is driven by the drive unit 95 in the C direction. And a pair of support arms 96 that move to each other.

  Two brackets 93 are provided apart in the C direction. The bracket 93 is fixed to, for example, the back side of the casing 11a of the irradiation nozzle 11. The trunnion mechanism portion 94 includes a ball screw (moving screw mechanism) 97 that converts rotational motion into linear motion, and a swing bracket 98 that swings in conjunction with the linear motion converted by the ball screw 97. The trunnion mechanism 94 is an example of a mechanism that converts linear motion into rotational motion.

  The ball screw 97 is swingably supported by the bracket 93. The ball screw 97 includes a screw shaft 99 that rotates and rotates, and a motor 100 that applies a rotational driving force to the screw shaft 99. As shown in FIG. 9, the ball screw 97 is arranged so that the lower end side is positioned behind the upper end side (the back panel 16 side) in a state where the gamma rays are not detected (retracted state). The bracket 93 is provided with an overhang portion 93a that projects rearward. The projecting portion 93a supports a pin 93b extending in the C direction. The ball screw 97 is supported by a pin 93 b and can swing with respect to the bracket 93. The ball screw 97 swings with respect to the pin 93b, and a connecting portion 98c (nut), which will be described later, advances and retreats in the axial direction with respect to the pin 93b.

  The swing bracket 98 is supported so as to be swingable with respect to the bracket 93. The swing bracket 98 is provided with an overhanging portion 98a that projects rearward (back panel side). The projecting portion 98a supports a pin 98b extending in the C direction. A connecting part (nut) 98c is connected to the screw shaft 99, and a pin 98b is supported by the connecting part 98C. Further, the bracket 93 is provided with an overhang portion 93c that projects downward. The projecting portion 93c supports a pin 93d extending in the C direction. The swing bracket 98 is supported by a pin 93 d and is configured to be swingable with respect to the bracket 93. The swing bracket 98 swings with reference to the pin 93d. The connecting portion 98c advances and retreats with respect to the screw shaft 99 in conjunction with the rotational movement of the screw shaft 99, and the overhanging portion 98a swings around the pin 93d as the rotation center in conjunction with the connecting portion 98c. Thereby, the swing bracket 98 swings by the ball screw 97. The connecting portion 98c moves linearly, and the driving force generated by the linear movement causes the support arm 96 to swing.

  The drive unit 95 has a drive mechanism for approaching or separating the pair of PET cameras 91. The drive unit 95 accommodates a ball screw (not shown) extending in the C direction, a drive source (for example, a motor, not shown) for applying a rotational driving force to the ball screw, and the ball screw and the drive source. A housing 95a is provided. For example, when the screw shaft of the ball screw is configured such that the screws are cut in different directions on both sides in the axial direction, the pair of PET cameras 91 can be moved closer to or away from each other by rotating the screw shaft. . Accordingly, the pair of PET cameras 91 can be moved in the C direction using one drive source. In addition, the structure which moves a pair of PET camera 91 by a some drive source may be sufficient.

  The housing 95 a is supported by a pair of swing brackets 98 and is configured to be swingable with respect to the bracket 93. The housing 95a is provided with a guide portion 95b for guiding the movement of the pair of support arms 96 in the C direction. And in the drive part 95, the rotational motion transmitted from the drive source is converted into a linear motion by a ball screw, and a pair of arms 96 and 96 move along the guide part 95b. Thereby, a pair of arms 96 and 96 move to a C direction, and mutually approach or space apart. The PET camera 91 can be brought close to the patient 61. By disposing the PET camera 91 close to the patient 61, the detection accuracy of annihilation gamma rays is improved.

  In addition, the proton therapy apparatus 10 includes a bed position control unit (not shown) that adjusts the position of the bed 22. The treatment table position control unit controls the position of the bed 22 on the basis of the PET image acquired by the PET apparatus 31 and the X-ray fluoroscopic image acquired by the X-ray imaging apparatus. The position of the bed 22 is adjusted by the robot arm 23 so that the proton beam is irradiated to the tumor 62 of the patient 61.

  The irradiation control unit 77 refers to the information stored in the tumor map (target map) 79 created based on the three-dimensional shape of the tumor 62 of the patient 61, in particular, the ridge filter unit 72, the fine degrader 73, And the operation of the multi-leaf collimator 76 is controlled. Here, the bolus 75 prepared in advance is set at a predetermined position so that the shape of the farthest part of the irradiation field is shaped corresponding to the complicated shape of the maximum depth portion of the tumor. Yes.

  Furthermore, the irradiation control unit 77 performs beam adjustment according to the arrival position of the proton beam detected by the PET apparatus 90. That is, the irradiation control unit 77 controls the operations of the ridge filter unit 72, the fine degrader 73, and the multi-leaf collimator 76 so that the actual arrival position of the proton beam in the patient 61 matches the position of the tumor 62. And adjust the proton beam.

  Next, a proton beam irradiation method (charged particle beam irradiation method) using the thus configured proton beam therapy apparatus 10 will be described.

When the proton beam therapy apparatus 10 is not used, the pair of PET cameras 91 are retracted to the side of the irradiation nozzle 11 (see FIG. 2). Here, as an example, proton beam therapy for a patient with a brain tumor will be described. First, the patient 61 is laid on the bed 22 in the rotating gantry 13. The longitudinal direction of the patient 61 is arranged along the direction in which the rotation axis P extends. Next, ¹¹ C methionine is administered to the patient 61 (S1), and waiting for ¹¹ C methionine to accumulate in the brain tumor (S2). Subsequently, annihilation gamma rays released from ¹¹ C methionine accumulated in the brain tumor are measured by the PET camera 91 (first detection step, S3). At this time, the motor 100 of the trunnion mechanism 94 is driven to swing the PET camera 91 and move in the irradiation direction A (downward in the drawing) from the retracted position beside the irradiation nozzle 11. That is, the PET cameras 91 are arranged on both sides of the patient 61. And the motor of the drive part 95 is driven, the PET camera 91 is moved to a C direction, and the space | interval of PET cameras 91 is adjusted. For example, when performing three-dimensional image measurement, the rotating gantry 12 is rotated to measure annihilation gamma rays.

  Next, based on the measurement result by the PET camera 91, a PET image is created to detect the position of the brain tumor (irradiation target position detection step, S4). Subsequently, fluoroscopic imaging is performed by the X-ray imaging apparatus to create an X-ray image of the patient 61 (X-ray fluoroscopic image acquisition step), and the positions of the bone and the metal marker are confirmed. Note that the order of PET imaging and X-ray imaging may be interchanged, and imaging may be performed multiple times alternately. Further, if necessary, the rotary gantry 12 is rotated to change the positions of the X-ray generator 81 and the X-ray detector 82.

  Next, an irradiation plan is made based on the PET image and the X-ray image (S6). Here, for example, the absolute dose, the dose distribution, the position of the patient 61, etc. are determined as the irradiation plan. Subsequently, based on the determined irradiation plan, the position of the bed 22 is adjusted (placement position adjustment step, S7), and the patient 61 is placed at an appropriate position.

  Next, beam adjustment is performed according to the determined irradiation plan, the rotating gantry 12 is rotated as necessary, the position of the irradiation nozzle 11 is changed, and a proton beam is irradiated once toward the tumor (S8). Then, annihilation gamma rays from the positron emission nuclei generated by the nuclear reaction between the irradiated proton beam and the nuclei in the patient 61 are measured by the PET camera 91 (second detection step, S9). At this time, the PET camera 91 is moved in the C direction so as to approach each other, and the PET camera 91 is brought close to the patient 61 to detect annihilation gamma rays. Further, the measurement may be performed by swinging the PET camera 91 with respect to the irradiation nozzle 11 or rotating around the rotation axis P. Subsequently, based on the measurement result by the PET camera 91, a PET image is created, the arrival position of the proton beam in the body of the patient 61 is detected, and the actual irradiation field is confirmed (charged particle beam arrival position detection step, S10). .

  According to such a proton beam therapy apparatus 10, the rotating gantry 12 is provided with the PET camera 91, which is generated by the nuclear reaction between the incident proton nucleus of the irradiated proton beam and the nucleus in the tumor. The annihilation gamma rays from the positron emitting nuclei can be measured, so that the arrival position of the actually irradiated proton beam can be confirmed. That is, the arrival position of the proton beam can be detected while irradiating the proton beam during treatment. Since the PET camera 91 is fixed to the irradiation nozzle 11 of the rotating gantry 12, the PET camera 91 can be rotated around the patient 61 in accordance with the rotation of the rotating gantry 12 and the irradiation nozzle 11, and the proton beam is An annihilation gamma ray can be measured immediately after irradiation. Further, the degree of freedom of movement of the PET camera 91 is improved, and three-dimensional measurement can be performed using the miniaturized PET camera 91, and there is no need to provide a separate rotation driving unit for the PET camera 91. . Further, since the PET camera 91 rotates in synchronization with the irradiation nozzle 11, it is possible to detect annihilation gamma rays while maintaining the positional relationship between the PET camera 91 and the irradiation nozzle 11 in the rotation direction.

  The PET camera 91 can move in the C direction and can be retracted to the side of the irradiation nozzle 11 (both sides in the C direction). Further, by appropriately moving the PET camera 91, the PET camera 91 does not hinder the rotation of the irradiation nozzle 11. Furthermore, the PET camera 91 does not get in the way when the patient 61 is brought into and out of the rotating gantry 12. Further, since the PET camera 91 can be moved in accordance with the size of the irradiated object, it is easy to confirm the irradiation position of a desired part.

  In addition, since the pair of PET cameras 91 can move in the C direction with the patient 61 interposed therebetween, and the distance between them can be arbitrarily changed, the PET camera 91 disappears when the PET camera 91 approaches the patient 61 in the C direction. The detection accuracy of gamma rays can be improved.

  Conventionally, for example, in radiotherapy for brain tumors, the head of the patient 61 has been fixed using a fixing tool in order to realize the positioning of the patient 61 with high accuracy, which has been a heavy burden on the patient 61. In the proton beam irradiation apparatus 10 and the proton beam irradiation method according to the present invention, the position of the tumor 62 can be confirmed using the PET camera 91 while the patient 61 is laid on the bed 22 in the irradiation chamber 21. And the position of the patient 61 can be positioned at an appropriate position. Thereby, since positioning of the patient 61 can be performed with high accuracy, simplification of fixing of the patient is achieved, and the burden on the patient can be reduced.

  In addition, the proton beam treatment apparatus 10 according to the present embodiment, the irradiation nozzle 11 that can rotate around the irradiated body, and a PET camera 91 that detects gamma rays generated from the irradiated body are radially arranged in the irradiation chamber 21. It is set as the structure which can evacuate to the outer side (parallel to the irradiation direction A). In the proton beam therapy apparatus 10, the PET camera 91 detection unit is moved to the vicinity of the irradiated object (near the rotation center) at the time of use, and retracted to the outside in the radial direction after use. Thereby, it is not necessary to adopt a conventional configuration in which the detection unit is retracted and accommodated along the rotation center axis P on the back side of the irradiation chamber 21. Therefore, the arrangement space of the beam introduction line 31 can be ensured on the back side closest to the irradiated body. As a result, in the proton beam treatment apparatus 10, the beam introduction line 31 is disposed in the space on the back side closest to the irradiated object, and therefore, interference between the PET camera 91 and the beam introduction line 31 is avoided and the proton beam treatment is performed. The apparatus 10 can be downsized.

In the proton beam therapy apparatus 10, a part of the beam introduction line 31 for transporting the proton beam is formed so as to pass through the second cylindrical portion 15, the cone portion 14, and the cylindrical main body portion 13 of the rotating gantry 12. Yes. In particular, the inclined portion 33 of the beam introduction line 31 is disposed obliquely so as to pass through the irradiation chamber 21 (cylindrical main body portion 13), and the beam introduction line 31 introduced from the back side of the rotating gantry 12 is connected to the rotating gantry. It can be derived from 12 sides. Therefore, compared with the conventional apparatus which does not arrange | position the beam transport line in the irradiation chamber 21, the projection amount (maximum outer diameter from an axial center) of a beam line can be made small. Thereby, size reduction of the proton beam therapy apparatus 10 can be achieved, and the installation space where the proton beam therapy apparatus 10 is installed can be made small. As a result, it is possible to reduce the size of the building 5 that houses the proton beam therapy apparatus 10. By downsizing the building, for example, the amount of concrete used for the radiation shielding wall of the building can be reduced, so that the construction cost of the building can be reduced. In addition, as shown in FIG. 2, the maximum rotation outer diameter of the proton beam therapy apparatus 10 can be 10.6 m (L ₁ × 2).

  The present invention is not limited to the above embodiment. In the above embodiment, the support arm 96 is swung using a ball screw, but may be swung using another driving device. For example, as shown in FIG. 12, the support arm 96 and the PET camera 91 may be swung by swinging the swing bracket 95 by the air cylinder 101.

  Further, as shown in FIG. 10, the proton therapy apparatus 10 is configured to swing the PET camera 91 by two motors 100. For example, as a drive source for moving the PET camera 91 in the radial direction, It is good also as a structure provided with the one motor 100. FIG. Thereby, simplification of an apparatus structure can be achieved.

  The support mechanism 92 is not limited to moving the PET camera 91 in the irradiation direction A by swinging the support arm 96, and is configured to move by moving the PET camera 91 linearly without swinging. But you can. The support mechanism 92 is capable of rotating around the rotation center axis P integrally with the irradiation nozzle 11 (charged particle beam irradiation unit) while supporting the PET camera 91 (detection unit), and also within the irradiation chamber 21. 11 is movable, and the PET camera 91 only needs to be able to advance and retreat in the radial direction in the rotation trajectory of the irradiation nozzle 11.

  The detection unit for detecting gamma rays is not limited to the PET camera 91, and may be other detectors. The number of detectors installed is not limited to two, and may be one or three or more.

  In the above embodiment, an X-ray apparatus is provided and X-ray imaging is performed. However, X-ray imaging may be omitted. In the above embodiment, the radiopharmaceutical is methionine, but other radiopharmaceuticals may be applied depending on the irradiation target. Moreover, in the said embodiment, although PET test | inspection using a radiopharmaceutical is implemented in an irradiation chamber, you may position a to-be-irradiated body using the data implemented in another place. Moreover, although the said embodiment demonstrated the brain tumor, you may apply with respect to another tumor.

  Moreover, the arrangement | positioning and number of each element arrange | positioned in the irradiation nozzle 11 can be changed suitably according to desired beam design.

  The particle accelerator is not limited to a cyclotron, and may be a synchrotron or a synchrocyclotron. The charged particle gland is not limited to a proton beam, and may be a carbon beam (heavy particle beam) or the like. Further, the cylindrical body of the rotating gantry 12 is not limited to a cylindrical shape, and may be another cylindrical shape. Further, the cylindrical body of the rotating gantry 12 may have the same shape in the rotation axis P direction.

  The rotating gantry 12 is not limited to one that rotates (oscillates) 360 °, and may rotate less than 360 °.

  In addition, the drive mechanism that moves the PET camera, which is a pair of detection units, closer to or away from the irradiated object in the width direction (C direction in the drawing) of the charged particle beam irradiation unit is not limited to a mechanism including a ball screw. Other moving screw mechanisms using trapezoidal screws, metric screws or the like may be used. By adopting a configuration including such a moving screw mechanism, a pair of PET cameras can be approached or separated by a single drive source.

  In the above embodiment, the trunnion mechanism is exemplified as the mechanism for converting the linear motion into the rotational motion, but a mechanism having another configuration may be used. In short, any configuration is possible as long as the linear motion is converted into the rotational motion and the support arm can be swung by the converted rotational motion. For example, as shown in FIG. 12, using a mechanism having a pin 103 provided at the tip of the output shaft 102 of the cylinder 101, the expansion / contraction motion (linear motion) of the output shaft 102 is transmitted to the bracket 95, and the bracket 93 Alternatively, the support arm 96 may be swung (rotated).

  DESCRIPTION OF SYMBOLS 1 ... Proton beam treatment system, 2 ... Cyclotron, 3 ... Beam transport line, 5 ... Building, 10 ... Proton beam treatment device (charged particle beam irradiation device), 11 ... Irradiation nozzle (irradiation part), 12 ... Rotating gantry, 13 ... Cylinder body part, 14 ... cone part, 15 ... second cylindrical part, 16 ... back panel, 21 ... irradiation chamber, 31 ... beam introduction line (beam transport line of rotating gantry), 61 ... patient, 62 ... tumor (subject) Irradiation body), 91 ... PET camera (detector), 92 ... PET camera support mechanism, 95 ... Drive unit (third direction drive unit), 96 ... Support arm, A ... Irradiation direction (second direction), B ... proton beam, C ... C direction (third direction), P ... central axis of rotation (first direction).

Claims (7)

In a charged particle beam irradiation apparatus including an irradiation chamber having a charged particle beam irradiation unit that can rotate around an irradiation object irradiated with a charged particle beam,
A detection unit for detecting gamma rays generated in the irradiated body;
A support mechanism capable of rotating and moving integrally with the charged particle beam irradiation unit while supporting the detection unit, and capable of moving the detection unit in the irradiation chamber;
The charged particle beam irradiation apparatus according to claim 1, wherein the support mechanism is capable of moving the detection unit back and forth in a radial direction in a rotation orbit of the charged particle beam irradiation unit.   The charged particle beam irradiation apparatus according to claim 1, wherein the support mechanism retracts the detection unit in a state where the gamma ray is not detected to a side of the charged particle beam irradiation unit. A PET camera that is a pair of the detection units that detect annihilation gamma rays generated in the irradiated body upon irradiation with the charged particle beam,
The pair of PET cameras are arranged on both sides of the irradiated body,
3. The charged particle beam irradiation apparatus according to claim 1, wherein the pair of PET cameras is movable in the radial direction by a single driving source that applies a driving force for moving the pair of PET cameras. The support mechanism includes a support arm that swingably supports the detection unit around a predetermined axis extending in the width direction of the charged particle beam irradiation unit,
The drive part which makes the said detection part approach or leave | separate with respect to the said to-be-irradiated body in the said width direction of the said charged particle beam irradiation part is provided. Charged particle beam irradiation equipment. The support mechanism has a mechanism for converting linear motion into rotational motion,
The charged particle beam irradiation apparatus according to claim 4, wherein the support arm swings when applied with the driving force transmitted by the mechanism.   The charged particle beam irradiation apparatus according to claim 5, wherein the support mechanism includes a trunnion mechanism that is supported by the charged particle beam irradiation unit and swings the support arm with respect to the charged particle beam irradiation unit.   The support mechanism includes a drive mechanism that causes a pair of the detection units, a PET camera, to approach or separate from the irradiated body in the width direction of the charged particle beam irradiation unit with a single drive source. The charged particle beam irradiation apparatus according to any one of claims 1 to 6.

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