JP2008173185A - Radiation treatment system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation treatment system for controlling the dose of radiation for treatment with higher precision. <P>SOLUTION: The radiation treatment system includes a waveguide tube 8 for forming a waveguide to transmit a high frequency from a high frequency source 5 to an acceleration tube 64, and a cooler for cooling the waveguide 8. The acceleration tube 64 accelerates charged particles 57 for generating the radiation 23 for the treatment by using the high frequency. The waveguide 8 sometimes generates heat, is deformed and varies transmission efficiency when transmitting the high frequency. The radiation treatment system reduces the deformation and reduces the variation of the transmission efficiency by cooling the waveguide 8. The radiation treatment system can reduce the variation of the energy (energy distribution) of the radiation 23 for the treatment, and control the dose of the radiation 23 for the treatment with higher precision. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radiotherapy system, and more particularly to a radiotherapy system used when treating a patient by irradiating an affected area with radiation.

  Radiotherapy is known in which a patient is treated by irradiating the affected part (tumor) with therapeutic radiation. The therapeutic radiation is exemplified by radiation generated by bremsstrahlung. The radiotherapy is desired to have a high therapeutic effect, and it is desired that the radiation dose to normal cells be smaller than the dose to the affected cells. There is known a radiotherapy apparatus that tracks the position of the affected area and irradiates the position with therapeutic radiation. It is desired to control the dose of therapeutic radiation with higher accuracy.

  Japanese Patent Laid-Open No. 2005-033463 eliminates the need for a choke structure that requires mechanical accuracy, thereby suppressing the attenuation of electromagnetic waves in the circular waveguide and also causing a risk of discharge from the circular waveguide. A waveguide rotary joint that can be reduced is disclosed. The waveguide rotary joint is a waveguide rotary joint in which a rectangular waveguide is joined to each end of a circular waveguide having a rotational coupling portion and both ends relatively rotatable about an axis. The electromagnetic wave transmitted in the TE10 mode in the input side rectangular waveguide is converted into the TE01 mode at the junction between the input side rectangular waveguide and the circular waveguide, and transmitted in the circular waveguide. The electromagnetic wave is again converted from the TE01 mode to the TE10 mode at the junction between the waveguide and the output side rectangular waveguide, and output to the output side rectangular waveguide.

  Japanese Patent No. 3746744 discloses a radiotherapy apparatus having excellent therapeutic performance. The radiotherapy apparatus includes an irradiation head having a therapeutic radiation generation unit including an electron gun, a linear accelerator, and a target, and a gimbal mechanism for swinging the therapeutic radiation generation unit, and the irradiation head on a predetermined spherical coordinate. A supporting and moving mechanism for supporting and moving; a microwave oscillator disposed at a stationary position for generating a microwave to be supplied to the irradiation head; and one end portion electromagnetically connected to the microwave oscillator and the other end A radiotherapy apparatus comprising: a waveguide unit electromagnetically connected to the linear accelerator; and the waveguide of the waveguide unit mounted on the gimbal mechanism, and the microwave oscillator It is characterized in that the waveguide of the waveguide section is connected by a flexible waveguide.

  Japanese Patent Application Laid-Open No. 62-206798 discloses a small and inexpensive linear accelerator with a small size and a light weight that are mounted on the accelerator body and joined to a microwave source with a flexible waveguide. Is disclosed. The linear accelerator is characterized in that the linear accelerator body and its microwave source are joined freely and vertically up and down by a waveguide that can be expanded and contracted.

  Japanese Examined Patent Publication No. 51-7389 discloses a rotary waveguide connector that reduces the overall configuration of the connector, makes it easy to align the axis and further increases the rotation angle range. The rotary waveguide connector includes a plurality of annular concave grooves concentrically opposed to the rotation axis on the surfaces of the fixed-side disk and the rotating-side disk overlapping with the fixed-side disk. Forming a plurality of annular waveguide paths, providing a waveguide connection port through which electromagnetic waves enter and exit from a part of each annular groove of both disks, and a wall surface adjacent to the waveguide connection port of each annular groove A partition for blocking the waveguide is provided to restrict the traveling direction of the electromagnetic wave in the pipeline.

  Japanese Utility Model Laid-Open No. 52-18073 discloses a rotary radiation therapy apparatus that performs treatment while rotating a radioisotope source container such as cobalt 60 around a patient. The rotary radiation therapy apparatus includes a mechanism for rotating a source container around a patient, a mechanism for rotating the container forward and backward, left and right on an axis parallel to the rotation center axis, and a radiation therapy apparatus having a rotation mechanism for an irradiation field. In the above, a cam for detecting whether or not the rotating body is in a specific steady position is provided in one of the rotating body and the stationary body with respect to each movement of the container, and two switches operated thereby are provided. In addition, this switch is added to the control circuit of each mechanism drive motor M, and each control circuit regulates the rotational direction when the rotating bodies are returned according to the operating state of the switches, and each rotating body is It is configured to automatically stop at this position when returning to its normal position.

JP 2005-033463 A Japanese Patent No. 3746744 Japanese Patent Laid-Open No. 62-206798 Japanese Patent Publication No.51-7389 Japanese Utility Model Publication No. 52-18073

An object of the present invention is to provide a radiotherapy system that controls the dose of therapeutic radiation with higher accuracy.
Another object of the present invention is to provide a radiotherapy system for controlling the dose of therapeutic radiation with higher accuracy when a waveguide for transmitting high frequency used for generation of therapeutic radiation includes a rotary joint. There is.
Still another object of the present invention is to provide a rotary joint that reduces fluctuations in transmission efficiency for transmitting high frequencies.

  In the following, means for solving the problems will be described using the reference numerals used in the best modes and embodiments for carrying out the invention in parentheses. This reference numeral is added to clarify the correspondence between the description of the claims and the description of the best mode for carrying out the invention / example, and is described in the claims. It should not be used to interpret the technical scope of the invention.

  The radiotherapy system according to the present invention comprises a waveguide (8) that forms a waveguide for transmitting a high frequency from a high frequency source (5) to an acceleration tube (64), and a cooler that cools the waveguide (8). I have. The acceleration tube (64) accelerates the charged particles (57) for generating therapeutic radiation (23) using high frequency. When transmitting a high frequency, the waveguide (8) may be deformed due to heat generation to change the transmission efficiency. The radiation therapy system can reduce the deformation by cooling the waveguide (8), and can reduce the fluctuation of the transmission efficiency. As a result, the radiotherapy system can reduce fluctuations in the energy of the charged particles (57) generated by the acceleration tube (64) and reduce fluctuations in the energy (energy distribution) of the therapeutic radiation (23). The dose of therapeutic radiation (23) can be controlled with higher accuracy.

  The waveguide (8) includes a rotary joint (75) whose other end is rotatable with respect to one end. The cooler cools the rotary joint (75). In the rotary joint (75), the transmission efficiency varies more greatly with respect to the deformation than the fixed waveguides (72, 73) that do not deform. The radiation therapy system can reduce the deformation by cooling the rotary joint (75) and reduce the fluctuation of the transmission efficiency. As a result, the radiotherapy system can reduce fluctuations in the energy of the charged particles (57) generated by the acceleration tube (64) and reduce fluctuations in the energy (energy distribution) of the therapeutic radiation (23). The dose of therapeutic radiation (23) can be controlled with higher accuracy.

  The waveguide (8) further includes a fixed waveguide (72, 73) adjacent to the rotary joint (75). The cooler preferably further cools the fixed waveguides (72, 73).

  The radiotherapy system according to the present invention further includes a nonreciprocal circuit element (77) interposed between the rotary joint (75) of the waveguide and the acceleration tube (64). The rotary joint (75) reflects the high frequency more than the fixed waveguide (72, 73). In the radiotherapy system, the non-reciprocal circuit element (77) is connected to the waveguide from the accelerator tube (64) to the high-frequency source in comparison with the high-frequency progression of the waveguide traveling from the high-frequency source (5) toward the accelerator tube (64). When the high-frequency reflection that travels toward (5) is attenuated, it is possible to prevent the cancellation of the high-frequency waves and the occurrence of waveform distortion, and to reduce fluctuations in transmission efficiency. As a result, the radiotherapy system can reduce fluctuations in the energy of the charged particles (57) generated by the acceleration tube (64) and reduce fluctuations in the energy (energy distribution) of the therapeutic radiation (23). The dose of therapeutic radiation (23) can be controlled with higher accuracy.

  The radiotherapy system according to the present invention includes a device (2, 6) that outputs a state of a waveguide, and a high frequency source (based on the state so that predetermined power is supplied to the acceleration tube (64) using high frequency. And a control device (7) for controlling 5). The radiotherapy system reduces the variation in energy of the charged particles (58) generated by the acceleration tube (64) when the transmission efficiency at which the waveguide (8) transmits high frequency changes depending on the state of the waveguide. It is possible to reduce variation in energy (energy distribution) of the therapeutic radiation (23). As a result, the radiation therapy system can control the dose of the therapeutic radiation (23) with higher accuracy.

  The rotary joint (75) according to the present invention forms a waveguide for transmitting a high frequency, and the rotary joint body (91, 92) in which the other end of the waveguide is rotatable with respect to one end of the waveguide; And a cooler for cooling the joint body (91, 92). When transmitting a high frequency, the rotary joint (75) may be deformed due to heat generation to change the transmission efficiency. Such a rotary joint (75) can reduce the deformation | transformation by cooling a rotary joint main body (91, 92), and can reduce the fluctuation | variation of the transmission efficiency.

  The radiotherapy system according to the present invention can control the dose of the therapeutic radiation with higher accuracy when the therapeutic radiation is generated using the high frequency transmitted through the waveguide. The rotary joint according to the present invention can reduce fluctuations in transmission efficiency for transmitting high frequencies.

  An embodiment of a radiation therapy system according to the present invention will be described with reference to the drawings. As shown in FIG. 1, the radiotherapy system 1 includes a radiotherapy device control device 2, a radiotherapy device 3, a klystron 5, a sensor 6, and a control device 7. The radiation therapy apparatus control apparatus 2 is a computer exemplified by a personal computer. The radiotherapy apparatus control apparatus 2 is connected to the radiotherapy apparatus 3 so that information can be transmitted bidirectionally. The klystron 5 controls the oscillation RF intensity, the klystron acceleration voltage, or the klystron current by the control device 7 to generate a high frequency with a predetermined power, and outputs the high frequency to the radiotherapy device 3 through the waveguide 8. Note that the control target need not be all three items, and only a part of them may be used. The same applies to each control target described below unless otherwise specified. The sensor 6 is formed from a device that measures the state of the waveguide 8. The apparatus includes a turning angle sensor 6-1, a traveling angle sensor 6-2, a pan angle sensor 6-3, a tilt angle sensor 6-4, and a transmission efficiency sensor 6-5. The control device 7 controls the klystron 5 based on the state measured by the sensor 6.

  FIG. 2 shows the radiation therapy apparatus 3. The radiotherapy device 3 includes a turning drive device 11, an O-ring 12, a traveling gantry 14, a swing mechanism 15, and a therapeutic radiation irradiation device 16. The swivel drive device 11 supports an O-ring 12 on a base so as to be rotatable about a rotation shaft 17, and is controlled by the radiotherapy device control device 2 to rotate the O-ring 12 around the rotation shaft 17, thereby The turning angle of the ring 12 is output. The rotating shaft 17 is parallel to the vertical direction. The O-ring 12 is formed in a ring shape with the rotation shaft 18 as a center, and supports the traveling gantry 14 so as to be rotatable about the rotation shaft 18. The rotating shaft 18 is perpendicular to the vertical direction and passes through an isocenter 19 included in the rotating shaft 17. The rotating shaft 18 is further fixed to the O-ring 12, that is, rotates around the rotating shaft 17 together with the O-ring 12. The traveling gantry 14 is formed in a ring shape centered on the rotation shaft 18, and is disposed so as to be concentric with the ring of the O-ring 12. The radiation therapy apparatus 3 further includes a travel drive device (not shown). The travel drive device is controlled by the radiotherapy device control device 2 to rotate the travel gantry 14 around the rotation shaft 18 and outputs the travel angle of the travel gantry 14 with respect to the O-ring 12.

  The swing mechanism 15 is fixed to the inside of the ring of the traveling gantry 14 and supports the therapeutic radiation irradiation device 16 on the traveling gantry 14 so that the therapeutic radiation irradiation device 16 is disposed inside the traveling gantry 14. Yes. The head swing mechanism 15 has a pan axis 21 and a tilt axis 22. The tilt shaft 22 is fixed to the traveling gantry 14 and is parallel to the rotation axis 18 without intersecting the rotation axis 18. The pan axis 21 is orthogonal to the pan axis 21. The head swing mechanism 15 is controlled by the radiation therapy apparatus control apparatus 2 to rotate the treatment radiation irradiation apparatus 16 about the pan axis 21 and rotate the treatment radiation irradiation apparatus 16 about the tilt axis 22.

  The therapeutic radiation irradiation device 16 is controlled by the radiotherapy device control device 2 to emit therapeutic radiation 23. The therapeutic radiation 23 is radiated substantially along a straight line passing through an intersection where the pan axis 21 and the tilt axis 22 intersect. The therapeutic radiation 23 is formed to have a uniform intensity distribution. The therapeutic radiation 23 is further partially shielded, and the shape of the irradiation field when the therapeutic radiation 23 is irradiated to the patient is controlled.

  The therapeutic radiation 23 is once adjusted so that the therapeutic radiation irradiation device 16 is directed to the isocenter 19 by the swing mechanism 15 by the therapeutic radiation irradiation device 16 being supported by the traveling gantry 14 in this manner. Even if the O-ring 12 is rotated by the turning drive device 11 or the traveling gantry 14 is rotated by the traveling drive device, the O-ring 12 always passes through the isocenter 19 at all times. In other words, the therapeutic radiation 23 can be irradiated from any direction toward the isocenter 19 by running and turning.

  The radiotherapy apparatus 3 further includes a plurality of imager systems. That is, the radiotherapy apparatus 3 includes diagnostic X-ray sources 24 and 25 and sensor arrays 32 and 33. The diagnostic X-ray source 24 is supported by the traveling gantry 14. The diagnostic X-ray source 24 is disposed inside the ring of the traveling gantry 14, and an angle formed by a line segment connecting the diagnostic X-ray source 24 from the isocenter 19 and a line segment connecting the therapeutic radiation irradiation device 16 from the isocenter 19. Is arranged at a position that makes an acute angle. The diagnostic X-ray source 24 is controlled by the radiotherapy apparatus controller 2 and emits diagnostic X-rays 35 toward the isocenter 19. The diagnostic X-ray 35 is a conical cone beam which is emitted from one point of the diagnostic X-ray source 24 and has the one point as a vertex. The diagnostic X-ray source 25 is supported by the traveling gantry 14. The diagnostic X-ray source 25 is disposed inside the ring of the traveling gantry 14, and an angle formed by a line segment connecting the diagnostic X-ray source 25 from the isocenter 19 and a line segment connecting the therapeutic radiation irradiation device 16 from the isocenter 19. Is arranged at a position that makes an acute angle. The diagnostic X-ray source 25 is controlled by the radiotherapy apparatus controller 2 and emits diagnostic X-rays 36 toward the isocenter 19. The diagnostic X-ray 36 is a cone-shaped cone beam emitted from one point of the diagnostic X-ray source 25 and having the one point as a vertex.

  The sensor array 32 is supported by the traveling gantry 14. The sensor array 32 receives the diagnostic X-ray 35 emitted from the diagnostic X-ray source 24 and transmitted through the subject around the isocenter 19 and generates a transmission image of the subject. The sensor array 33 is supported by the traveling gantry 14. The sensor array 33 receives the diagnostic X-ray 36 emitted from the diagnostic X-ray source 25 and transmitted through the subject around the isocenter 19 and generates a transmission image of the subject. Examples of the sensor arrays 32 and 33 include FPD (Flat Panel Detector) and X-ray II (Image Intensifier).

  According to such an imager system, a transmission image centered on the isocenter 19 can be generated based on the image signals obtained by the sensor arrays 32 and 33.

  The radiation therapy apparatus 3 further includes a sensor array 31. The sensor array 31 is arranged so that a line segment connecting the sensor array 31 and the therapeutic radiation irradiation device 16 passes through the isocenter 19 and is fixed inside the ring of the traveling gantry 14. The sensor array 31 receives the therapeutic radiation 23 emitted from the therapeutic radiation irradiation device 16 and transmitted through the subject around the isocenter 19, and generates a transmission image of the subject. Examples of the sensor array 31 include FPD (Flat Panel Detector) and X-ray II (Image Intensifier).

  The radiation therapy apparatus 3 further includes a couch 41 and a couch driving device 42. The couch 41 is used when a patient 43 to be treated by the radiation therapy system 1 lies down. The couch 41 includes a fixture not shown. The fixture secures the patient to the couch 41 so that the patient does not move. The couch driving device 42 supports the couch 41 on the base and moves the couch 41 under the control of the radiation therapy device control device 2.

  FIG. 3 shows the therapeutic radiation irradiation device 16. The therapeutic radiation irradiation device 16 includes an electron beam accelerator 51, an X-ray target 52, a primary collimator 53, a flattening filter 54, a dosimeter 61, a secondary collimator 55, and a multi-leaf collimator 56. The electron beam accelerator 51 irradiates the X-ray target 52 with an electron beam 57 generated by accelerating electrons. The X-ray target 52 is formed of a high atomic number material (tungsten, tungsten alloy, etc.), and emits radiation 59 generated by bremsstrahlung when the electron beam 57 is irradiated. The radiation 59 is radiated substantially along a straight line passing through a virtual point source 58, which is a point inside the X-ray target 52. The primary collimator 53 is made of a high atomic number material (lead, tungsten, etc.), and shields the radiation 59 so that the radiation 59 is not irradiated to other than the desired part. The flattening filter 54 is formed of aluminum or the like, and is formed on a plate on which a generally conical protrusion is formed. The flattening filter 54 is disposed so that its protrusion faces the X-ray target side. The flattening filter shape is formed so that the dose in a predetermined region on a plane perpendicular to the radiation direction is distributed substantially uniformly after passing through the flattening filter. The secondary collimator 55 is formed from a high atomic number material (lead, tungsten, etc.), and shields the radiation 60 so that the radiation 60 is not irradiated to other than a desired part. The radiation 60 having a uniform intensity distribution formed in this way is partially shielded by the multi-leaf collimator 56 controlled by the radiation therapy apparatus control apparatus 2 and has a property based on a separately constructed treatment plan. A certain therapeutic radiation 23 is generated. That is, the multi-leaf collimator 56 is controlled by the radiation therapy apparatus control apparatus 2 to control a shape of an irradiation field when the patient is irradiated with the therapeutic radiation 23 by shielding a part of the radiation 60.

  The dosimeter 61 is a transmission ionization chamber that measures the intensity of transmitted radiation, and is disposed between the primary collimator 53 and the secondary collimator 55 so that the radiation 60 is transmitted. The dosimeter 61 measures the dose of the transmitted radiation 60 and outputs the intensity to the radiation therapy apparatus control apparatus 2. Such a dosimeter 61 is preferable in that non-destructive verification is possible. The X-ray intensity detector other than the transmission ionization chamber can be applied to the dosimeter 61. Examples of the X-ray intensity detector include a semiconductor detector and a scintillation detector. The semiconductor detector or the scintillation detector is preferably disposed outside the orbit because it is difficult to substitute the radiation detector on the radiation orbit like a transmission ionization chamber. For example, the therapeutic radiation is separated from the isocenter 19. The traveling gantry 14 is fixed so as to be disposed at a position facing the irradiation device 16. An ionization chamber generally has a time constant of about several seconds and has poor responsiveness. The semiconductor detector or the scintillation detector has a disadvantage that the signal intensity is lower than that of the ionization chamber when placed outside the orbit, but it is preferable because it has better response than the ionization chamber.

  The electron beam accelerator 51 includes an electron beam generator 63 and an acceleration tube 64. The electron beam generator 63 includes a cathode 66 and a grid 67. The acceleration tube 64 is formed in a cylindrical shape, and includes a plurality of electrodes 68 arranged at appropriate intervals inside the cylinder. The radiotherapy apparatus 3 further includes a cathode power supply 70, a grid power supply 69, and a klystron 5. The cathode power supply 70 is controlled by the radiotherapy device controller 2 so that the cathode 66 is heated and a predetermined amount of electrons are emitted from the cathode 66 (that is, the cathode 66 is maintained at a predetermined temperature). ), Power is supplied to the cathode 66. The grid power supply 69 is controlled by the radiotherapy apparatus control device 2 to apply a predetermined voltage between the grid 67 and the cathode 66 so that only a predetermined amount of electrons are emitted from the electron beam generator 63. . The klystron 5 is connected to the acceleration tube 64 via the waveguide 8. The klystron 5 is controlled by the radiotherapy device controller 2 and is accelerated through the waveguide 8 so that the accelerator tube 64 accelerates electrons emitted from the electron beam generator 63 until it has a predetermined energy. A microwave is incident on 64. The klystron 5 can be replaced with another high-frequency source. Examples of the high frequency source include a magnetron and a multipolar tube.

  As shown in FIG. 4, the klystron 5 is supported by a base on which the radiation therapy apparatus 3 is supported. The waveguide 8 forms a waveguide through which the high frequency generated by the klystron 5 propagates. The waveguide 8 includes fixed waveguides 71, 72, 73, a flexible waveguide 74, and a rotary joint 75. The fixed waveguide 71 forms a waveguide that does not deform, and is supported by the base. The fixed waveguide 72 forms a waveguide that does not deform, and is supported by the turntable 76. The turntable 76 is supported by the turning drive device 11 so as to be rotatable about the rotation shaft 17, and is rotated about the rotation shaft 17 in the same body as the O-ring 12. For this reason, the fixed waveguide 72 rotates around the rotation axis 17 in the same body as the O-ring 12. The fixed waveguide 73 forms a waveguide that does not deform, is supported by the traveling gantry 14, and moves together with the traveling gantry 14.

  The flexible waveguide 74 is formed in a bellows structure and forms a waveguide that can be bent and stretched. The flexible waveguide 74 has one end connected to the fixed waveguide 71 and the other end connected to the fixed waveguide 72. The flexible waveguide 74 is deformed by the rotation of the O-ring 12 with respect to the base, and the shape of the flexible waveguide 74 generally corresponds to the turning angle of the O-ring 12 with respect to the base. That is, the turning angle at which the O-ring 12 rotates about the rotation axis 17 with respect to the base is limited by the range in which the flexible waveguide 74 can be deformed.

  The rotary joint 75 forms a deformable waveguide and is disposed so as to overlap the rotation shaft 18. The rotary joint 75 has one end connected to the fixed waveguide 72 and the other end connected to the fixed waveguide 73.

  As shown in FIG. 5, the fixed waveguide 73 has an end opposite to the end connected to the rotary joint 75 in the vicinity of the swing mechanism 15. The waveguide 8 further includes a circulator 77 as shown in FIG. The circulator 77 is disposed in the middle of the fixed waveguide 73. The circulator 77 attenuates the reflected wave traveling from the acceleration tube 64 toward the klystron 5 as compared with the high frequency traveling through the fixed waveguide 73 from the klystron 5 toward the acceleration tube 64. A part of the microwave incident on the acceleration tube 64 is reflected. This reflectance is constant depending on the resonance degree of the acceleration tube. In addition, a part of the microwave is reflected by a free waveguide such as the rotary joint 75. For this reason, a part of the reflected wave from the accelerating tube 64 travels toward the accelerating tube 64 after being reflected again by the free waveguide. However, since the circulator 77 is provided, it is possible to distribute the reflected wave from the accelerating tube outside the system. As a result, the microwave supplied from the klystron 5 is superimposed on the reflected microwave. It is possible to suppress cancellation and distortion.

  FIG. 6 shows the swing mechanism 15. The head swing mechanism 15 includes an irradiation device support 81 and an intermediate body 82. The irradiation device support 81 is supported by the traveling gantry 14 and moves in the same body as the traveling gantry 14. The tilt shaft 22 is fixed with respect to the irradiation device support 81. The intermediate body 82 is supported by the irradiation apparatus support body 81 so as to be rotatable about the tilt shaft 22. The intermediate body 82 is supported by the irradiation apparatus support body 81 so as to be rotatable about the tilt shaft 22. Further, when the intermediate body 82 rotates around the tilt shaft 22, the range in which the intermediate body 82 can rotate by contacting a part of the irradiation device support 81 is limited. The pan shaft 21 is fixed with respect to the intermediate body 82. The therapeutic radiation irradiation device 16 is supported by the intermediate body 82 so as to be rotatable about the pan shaft 21. Further, when the therapeutic radiation irradiation device 16 rotates about the pan axis 21, the range in which the therapeutic radiation irradiation device 16 can rotate by contacting a part of the intermediate body 82 is limited. Such a limitation makes the range in which the therapeutic radiation irradiation device 16 moves by the swing mechanism 15 smaller than the range in which the therapeutic radiation irradiation device 16 moves by the turning drive device 11 and the traveling drive device.

  The swing mechanism 15 further includes a pan axis driving device and a tilt axis driving device which are not shown. The pan axis driving apparatus is controlled by the radiotherapy apparatus control apparatus 2 to rotate the therapeutic radiation irradiation apparatus 16 about the pan axis 21. The tilt axis driving device is controlled by the radiation therapy apparatus control device 2 to rotate the intermediate body 82 about the tilt axis 22.

  The waveguide 8 further includes a fixed waveguide 84, a fixed waveguide 85, a flexible waveguide 86, and a flexible waveguide 87. The fixed waveguide 84 forms a waveguide that does not deform, is supported by the intermediate body 82, and moves in the same body as the intermediate body 82. The fixed waveguide 85 forms a waveguide that does not deform, is supported by the therapeutic radiation irradiation device 16, and moves in the same body as the therapeutic radiation irradiation device 16. One end of the fixed waveguide 85 is connected to the acceleration tube 64. The flexible waveguide 86 and the flexible waveguide 87 are formed in a bellows structure (bellows), and form a waveguide that can be bent and stretched. The flexible waveguide 86 is arranged so that its longitudinal direction is perpendicular to the tilt axis 22 and overlaps the tilt axis 22. The flexible waveguide 86 has one end connected to the fixed waveguide 73 and the other end connected to the fixed waveguide 84. The flexible waveguide 86 is deformed by the rotation of the therapeutic radiation irradiation device 16 with respect to the intermediate body 82, and the shape of the flexible waveguide 86 is set to the tilt angle of the therapeutic radiation irradiation device 16 with respect to the intermediate body 82. Mostly supported. The flexible waveguide 87 is disposed so that the longitudinal direction is perpendicular to the pan axis 21 and overlaps the pan axis 21. The flexible waveguide 87 has one end connected to the fixed waveguide 84 and the other end connected to the acceleration tube 64 of the therapeutic radiation irradiation device 16. The flexible waveguide 87 is deformed by rotating the intermediate body 82 with respect to the irradiation apparatus support 81, and the shape of the flexible waveguide 87 substantially corresponds to the pan angle of the intermediate body 82 with respect to the irradiation apparatus support 81. is doing. Such an arrangement is preferable in that the bending absorbability of the flexible waveguide 86 and the flexible waveguide 87 is utilized.

  FIG. 7 shows the rotary joint 75. The rotary joint 75 includes a first cylinder portion 91 and a second cylinder portion 92. The first cylinder portion 91 is formed in a cylindrical shape centered on the rotation shaft 93. The second cylinder portion 92 is formed in a cylindrical shape centered on the rotation shaft 93 and is supported by the first cylinder portion 91 so as to be rotatable about the rotation shaft 93. The first cylinder portion 91 has a part of the side surface of the cylinder connected to one end of the fixed waveguide 72. The second cylinder portion 92 has a part of the side surface of the cylinder connected to one end of the fixed waveguide 73. The rotary joint 75 is arranged in the radiation therapy apparatus 3 so that the rotation shaft 93 overlaps the rotation shaft 18. That is, in the rotary joint 75, the second cylinder portion 92 rotates with respect to the first cylinder portion 91 when the traveling gantry 14 rotates with respect to the O-ring 12. At this time, the angle of the second cylinder portion 92 with respect to the first cylinder portion 91 corresponds to the traveling angle of the traveling gantry 14 with respect to the O-ring 12.

  The rotary joint 75 rotatably connects the fixed waveguide 72 and the fixed waveguide 73, and connects the fixed waveguide 72 and the fixed waveguide 73 so that a high frequency can be transmitted. Such a rotary joint 75 is well known and is disclosed in, for example, Japanese Patent Application Laid-Open No. 2005-033463.

  As shown in FIG. 8, the rotary joint 75 includes a bearing 94. The bearing 94 is disposed in a gap 99 between the first cylinder portion 91 and the second cylinder portion 92. The bearing 94 supports the second cylinder portion 92 on the first cylinder portion 91 so as to be rotatable about the rotation shaft 93.

  The rotary joint 75 further includes water-cooled tubes 95, 96, and 97. Each of the water-cooled tubes 95, 96, and 97 includes a tube (not shown) therein. The water-cooled tube 95 is in contact with the end of the fixed waveguide 72 on the side connected to the rotary joint 75 so as to conduct heat. The water-cooled tube 95 cools the end of the fixed waveguide 72 on the side connected to the rotary joint 75 by flowing cold water through the internal tube. The water-cooled tube 96 is in contact with the end of the fixed waveguide 73 on the side connected to the rotary joint 75 so as to conduct heat. The water-cooled tube 96 cools the end of the fixed waveguide 73 on the side connected to the rotary joint 75 by flowing cold water through the internal tube. The water-cooled tube 97 is in contact with the first tube portion 91 so as to be able to conduct heat. The water-cooled pipe 96 cools the rotary joint 75 by flowing cold water through the internal pipe. The water cooling tubes 95, 96, and 97 can be replaced with other coolers. Examples of the cooler include a cooler using another refrigerant different from water and an electronic cooler using a Peltier element.

  The rotary joint 75 is deformed due to temperature changes such as heat generated by high-frequency transmission including ambient temperature and leakage from the gap 99 in addition to the effects of processing / assembly accuracy of each component and external force. Such deformation increases or decreases the size of the gap 99, and changes the transmission efficiency at which the rotary joint 75 transmits high frequency. For this reason, the fluctuation | variation of the transmission efficiency accompanying a temperature change can be suppressed by hold | maintaining the rotary joint 75 at fixed temperature with a cooling means.

Here, the turning angle sensor 6-1 measures the rotation angle at which the O-ring 12 rotates about the rotation shaft 17 with respect to the base, and outputs the rotation angle to the control device 7. The traveling angle sensor 6-2 measures a rotation angle at which the second cylinder portion 92 rotates about the rotation axis 93 with respect to the first cylinder portion 91, and outputs the rotation angle to the control device 7. The pan angle sensor 6-3 measures the rotation angle at which the therapeutic radiation irradiation device 16 rotates about the pan axis 21 with respect to the intermediate body 82, and outputs the rotation angle to the control device 7. The tilt angle sensor 6-4 measures a rotation angle at which the intermediate body 82 rotates about the tilt axis 22 with respect to the irradiation device support 81, and outputs the rotation angle to the control device 7. The transmission efficiency sensor 6-5 is disposed in a portion of the waveguide 8 close to the acceleration tube 64 (for example, in the middle of the fixed waveguide 85), and the electric power of the high frequency travel transmitted by the waveguide 8 is transmitted. And the reflected power are measured, and the transmission efficiency for the waveguide 8 to transmit a high frequency is generated. Such a transmission efficiency sensor 6-5 is well known, for example, a sensor using a directional coupler.
If the resonance degree of the accelerating tube can be considered to be constant, the transmission efficiency sensor 6-5 measures only the high-frequency progressing power transmitted by the waveguide 8, thereby the waveguide 8 Indirect evaluation of physical quantities corresponding to transmission efficiency for transmitting high frequencies is also possible.
In general, a flexible waveguide has a smaller change in reflectance with respect to a state than a rotary joint, and a flexible / expandable range, that is, a state changeable range is small. For this reason, if the flexible waveguide has negligible state dependency of the reflectance under the usage conditions, the measurement target may be only the rotary joint part. In the present embodiment, the following description will be made in the case where the state of the flexible waveguide portion is also measured.

  FIG. 9 shows the control device 7. The control device 7 is a computer, and includes a CPU, a storage device, an input device, an output device, and an interface (not shown). The CPU executes a computer program installed in the control device 7 to control the storage device, the input device, the output device, and the interface. The storage device records the computer program, records information used by the CPU, and records information generated by the CPU. The input device outputs information generated by being operated by the user to the CPU. Examples of the input device include a keyboard and a mouse. The output device outputs the information generated by the CPU so that the user can recognize it. Examples of the output device include a display that displays a screen generated by the CPU. The interface outputs information generated by an external device connected to the control device 7 to the CPU, and outputs information generated by the CPU to the external device. The external device includes a klystron 5 and a sensor 6.

  The control device 7 includes a control database 101 that is a computer program, a state collection unit 102, and a control unit 103.

  The control database 101 records a control table indicating the relationship between the measurement value measured by the sensor 6 and the control value for controlling the klystron 5 in a storage device so as to be searchable by other computer programs.

  The state collection unit 102 collects measurement values measured by the sensor 6 from the sensor 6. That is, the state collection unit 102 collects the turning angle at which the O-ring 12 rotates about the rotation shaft 17 with respect to the base from the turning angle sensor 6-1. The state collection unit 102 further collects, from the travel angle sensor 6-2, the travel angle at which the second tube portion 92 rotates about the rotation shaft 93 with respect to the first tube portion 91. The state collection unit 102 further collects, from the pan angle sensor 6-3, the pan angle at which the therapeutic radiation irradiation device 16 rotates about the pan axis 21 with respect to the intermediate body 82. The state collection unit 102 further collects from the tilt angle sensor 6-4 the tilt angle at which the intermediate body 82 rotates about the tilt axis 22 with respect to the irradiation device support 81. The state collection unit 102 further collects the high frequency traveling power and the reflected power transmitted by the waveguide 8 from the transmission efficiency sensor 6-5.

  The control unit 103 refers to the control table recorded by the control database 101 and controls the klystron 5 based on the measurement values collected by the state collection unit 102.

  FIG. 10 shows a control table recorded by the control database 101. In the control table 104, the turning angle 105, the traveling angle 106, the pan angle 107, and the tilt angle 108 are associated with the control amount 109. That is, a combination of an arbitrary element of the turning angle 105, an arbitrary element of the traveling angle 106, an arbitrary element of the pan angle 107, and an arbitrary element of the tilt angle 108 Corresponds to one of these elements. A swivel angle 105 indicates the shape of the flexible waveguide 74 and indicates a rotation angle at which the O-ring 12 rotates about the rotation axis 17 with respect to the base. The travel angle 106 indicates the shape of the rotary joint 75 and indicates the rotation angle at which the second cylinder portion 92 rotates about the rotation axis 93 with respect to the first cylinder portion 91. A pan angle 107 indicates the shape of the flexible waveguide 87 and indicates a rotation angle at which the therapeutic radiation irradiation device 16 rotates about the pan axis 21 with respect to the intermediate body 82. The tilt angle 108 indicates the shape of the flexible waveguide 86 and indicates the rotation angle at which the intermediate body 82 rotates about the tilt axis 22 with respect to the irradiation apparatus support 81. The control amount 109 indicates a control amount used when controlling the klystron 5 when the turning angle, the running angle, the pan angle, and the tilt angle are measured by the sensor 6, and the oscillation RF intensity, the klystron acceleration voltage, or the klystron current. Is shown.

  At this time, the control unit 103 refers to the control table 104, calculates a control amount corresponding to the combination of the turning angle, the traveling angle, the pan angle, and the tilt angle collected by the state collection unit 102, and the klystron 5 The klystron 5 is controlled so that the oscillation RF intensity, the klystron acceleration voltage, or the klystron current respectively matches the oscillation RF intensity, the klystron acceleration voltage, or the klystron current indicated by the control amount. The control unit 103 further controls the oscillation RF intensity or the klystron so that predetermined power is supplied to the acceleration tube 64 based on the high-frequency traveling power and the reflected power collected by the state collecting unit 102. Feedback control of acceleration voltage or klystron current.

  That is, the control table 104 accelerates when the controller 7 controls the klystron 5 based on the control amount corresponding to the combination of the turning angle, the traveling angle, the pan angle, and the tilt angle collected by the state collection unit 102. It is created so that constant power is supplied to the tube 64.

  In radiation therapy using the radiation therapy system 1, a user first creates a treatment plan using the radiation therapy apparatus control device 2. The treatment plan shows an irradiation angle at which the affected part of the patient 43 is irradiated with the therapeutic radiation 23 and a dose and a property of the therapeutic radiation 23 irradiated from each irradiation angle. The radiotherapy device control apparatus 2 repeatedly executes the tracking operation and the irradiation operation. In the tracking operation, the radiation therapy apparatus control device 2 calculates the affected part position based on the image captured by the imager system of the radiation therapy apparatus 3. The affected part position calculation may be based on the position of a landmark different from the affected part. Examples of the landmark include an organ and an object that move in conjunction with the affected part. Examples of the organ include bone (radius), diaphragm and bladder. The object is formed from the material detected by the imager system and is implanted in the patient's body to move in conjunction with the affected area. As the object, a gold marker which is a sphere formed from gold is exemplified. The radiotherapy device control apparatus 2 moves the therapeutic radiation irradiation device 16 using the swing mechanism 15 so that the therapeutic radiation 23 passes through the affected area. In the irradiation operation, the radiotherapy device control apparatus 2 irradiates the affected area with the therapeutic radiation 23 using the therapeutic radiation irradiation device 16 immediately after the therapeutic radiation irradiation device 16 is moved by the tracking operation.

  The control device 7 operates in parallel with the irradiation operation. First, the control device 7 collects the turning angle at which the O-ring 12 rotates about the rotation shaft 17 with respect to the base from the turning angle sensor 6-1. The control device 7 further collects a traveling angle at which the second cylinder portion 92 rotates about the rotation shaft 93 with respect to the first cylinder portion 91 from the traveling angle sensor 6-2. The control device 7 further collects, from the pan angle sensor 6-3, the pan angle at which the therapeutic radiation irradiation device 16 rotates about the pan axis 21 with respect to the intermediate body 82. The control device 7 further collects from the tilt angle sensor 6-4 the tilt angle at which the intermediate body 82 rotates about the tilt axis 22 with respect to the irradiation device support 81. The control device 7 further collects the power of the high frequency traveling and the power of reflection transmitted from the waveguide 8 from the transmission efficiency sensor 6-5.

  The control device 7 refers to the control table 104 and calculates a control amount corresponding to the combination of the turning angle, the traveling angle, the pan angle, and the tilt angle measured by the sensor 6. The control device 7 controls the klystron 5 such that the oscillation RF intensity, the klystron acceleration voltage, or the klystron current of the klystron 5 matches the oscillation RF intensity, the klystron acceleration voltage, or the klystron current indicated by the control amount. Further, the control device 7 oscillates RF intensity so that predetermined power is supplied to the acceleration tube 64 based on the high frequency power and the reflected power measured by the transmission efficiency sensor 6-5. Alternatively, the klystron acceleration voltage or the klystron current is feedback controlled. The control device 7 periodically repeats such an operation.

  In general, the waveguide 8 generates heat and deforms by transmitting a high frequency, and the transmission efficiency for transmitting the high frequency varies. In particular, the size of the gap 99 increases or decreases in the rotary joint 75 due to the deformation thereof, and the transmission efficiency varies more greatly than the fixed waveguides 71, 72, 73, 84, and 85. Further, the waveguide 8 is also deformed by a change in ambient temperature. The radiation therapy system 1 according to the present invention cools the rotary joint 75 and the fixed waveguides 72 and 73 to reduce the temperature fluctuation of the waveguide 8 (particularly, the rotary joint 75) and reduce its deformation. Thus, fluctuations in the transmission efficiency can be reduced. As a result, the radiotherapy system 1 according to the present invention can reduce fluctuations in the energy (energy distribution) of the therapeutic radiation 23 and can control the dose of the therapeutic radiation 23 with higher accuracy.

  Note that the rotary joint 75 may include only some water cooling tubes selected from the water cooling tubes 95, 96, and 97. At this time as well, the radiotherapy system 1 according to the present invention can similarly reduce the variation in the temperature of the rotary joint 75, reduce its deformation, and reduce the variation in its transmission efficiency. The radiotherapy system 1 according to the present invention can further include other water-cooled tubes. The water-cooled tube is in thermal contact with several waveguides selected from the fixed waveguides 71, 72, 73, 84, 85 and the flexible waveguides 74, 86, 87. At this time, the radiotherapy system 1 according to the present invention further reduces the fluctuation of the temperature of the waveguide 8 and further reduces the deformation of the waveguide 8 to further reduce the fluctuation of the transmission efficiency of the waveguide 8. Can be reduced.

  FIG. 11 shows the relationship between the rotation angle of the second cylinder portion 92 relative to the first cylinder portion 91 of the rotary joint 75 and the high-frequency transmission efficiency. The relation 111 indicates that the transmission efficiency corresponding to the rotation angle θ is equal to the transmission efficiency corresponding to the rotation angle θ + 2πn using an arbitrary integer n, and other different rotation angles θ ′ (θ ′ ≠ θ + 2πn). It is shown that the transmission efficiency may differ from that in FIG. That is, the relationship 111 indicates that the transmission efficiency changes as the first cylinder portion 91 and the second cylinder portion 92 of the rotary joint 75 rotate. Further, the absolute value of the fluctuation amount is not necessarily the same even in the opposite phase, and generally Δa and Δb are different. Although such a change in transmission efficiency cannot theoretically occur, a part of the rotary joint 75 (for example, the first cylinder portion 91 and the second cylinder) is rotated by the rotation due to the mechanical accuracy and assembly accuracy of the components. This is caused by a change in the degree of the clearance between the portion 92 and the coupling coefficient between the two cylindrical portions. As described above, this change further increases due to the temperature change of the rotary joint 75.

  Note that the flexible waveguides 74, 86, and 87 also change the transmission efficiency in accordance with the deformation in the same manner as the rotary joint 75. That is, the transmission efficiency of the flexible waveguide 74 changes as the O-ring 12 rotates about the rotation axis 17 with respect to the base, and the transmission efficiency corresponds to the turning angle. The transmission efficiency of the flexible waveguide 86 changes as the intermediate body 82 rotates about the tilt axis 22 with respect to the irradiation device support 81, and the transmission efficiency corresponds to the tilt angle. The flexible waveguide 87 changes its transmission efficiency as the therapeutic radiation irradiation device 16 rotates about the pan axis 21 with respect to the intermediate body 82, and the transmission efficiency corresponds to the pan angle.

  FIG. 12 shows the relationship between the rotation angle of the second cylindrical portion 92 relative to the first cylindrical portion 91 of the rotary joint 75 and the high-frequency transmission efficiency when the waveguide 8 does not include the circulator 77. The transmission efficiency of the waveguide 8 is a portion closer to the acceleration tube 64 than the free waveguide (flexible waveguides 74, 86, 87, rotary joint 75) (for example, in the middle of the fixed waveguide 85). It is measured. The relationship 121 indicates that the transmission efficiency corresponding to the rotation angle θ is equal to the transmission efficiency corresponding to the rotation angle θ + 2πn, and is different from the transmission efficiency corresponding to another different rotation angle θ ′ (θ ′ ≠ θ + 2πn). It shows that there is. That is, the relationship 121 indicates that the transmission efficiency changes as the first cylinder portion 91 and the second cylinder portion 92 of the rotary joint 75 rotate. Such a change in transmission efficiency cannot theoretically occur. However, due to the mechanical accuracy and assembly accuracy of the components, a part of the rotary joint 75 (for example, the first tube portion 91 and the second tube portion) is rotated by the rotation. This occurs due to a change in the degree of clearance between the cylinder portion 92 and the coupling coefficient between the cylinder portions.

  FIG. 12 further shows the relationship between the rotation angle of the second cylindrical portion 92 relative to the first cylindrical portion 91 of the rotary joint 75 and the high-frequency transmission efficiency when the waveguide 8 includes the circulator 77. The relationship 122 indicates that the transmission efficiency corresponding to the rotation angle θ is equal to the transmission efficiency corresponding to the rotation angle θ + 2πn, and is different from the transmission efficiency corresponding to another different rotation angle θ ′ (θ ′ ≠ θ + 2πn). Further, it is shown that the magnitude of the fluctuation in transmission efficiency is smaller than the magnitude of the transmission efficiency indicated by the relation 121. That is, FIG. 12 shows that the waveguide 8 includes the circulator 77, so that the magnitude of fluctuations in high-frequency transmission efficiency transmitted by the waveguide 8 can be reduced. Originally, it is also necessary to further correct the transmission efficiency variation due to the temperature change of the rotary joint 75. However, in the present invention, the influence of the change is suppressed by providing the rotary joint 75 with the cooling means, so it is simpler. In addition, the magnitude of fluctuation can be reduced stably.

  FIG. 13 shows the relationship between the rotation angle of the rotary joint 75 and the high-frequency power output from the klystron 5 when the control device 7 does not control the klystron 5 based on the measurement value of the sensor 6. The relationship 112 indicates that the high-frequency power is independent of the rotation angle, and indicates that the high-frequency power is constant. FIG. 13 further shows the rotation angle of the rotary joint 75 and the output from the klystron 5 when the control device 7 controls the klystron 5 based on the measurement value of the sensor 6 when the flexible waveguides 74, 86 and 87 are not deformed. It shows the relationship with the high frequency power. The relationship 113 indicates that the high-frequency power corresponds to the rotation angle, and that the high-frequency power corresponding to the rotation angle θ is equal to the high-frequency power corresponding to the rotation angle θ + 2πn. That is, the control device 7 controls the klystron 5 so that the high frequency power corresponds to the rotation angle and the high frequency power corresponding to the rotation angle θ corresponds to the rotation angle θ + 2πn.

  FIG. 14 shows the relationship between the rotation angle of the rotary joint 75 and the power input to the acceleration tube 64 when the klystron 5 outputs a high frequency as shown in the relationship 112. The relationship 114 indicates that the power corresponding to the rotation angle θ is equal to the power corresponding to the rotation angle θ + 2πn, and may be different from the power corresponding to another different rotation angle θ ′ (θ ′ ≠ θ + 2πn). Show. FIG. 12 further shows the relationship between the rotation angle of the rotary joint 75 and the power input to the acceleration tube 64 when the klystron 5 outputs a high frequency as shown in the relationship 113. The relationship 115 indicates that the power is independent of the rotation angle, and indicates that the power is constant.

  Further, the radiotherapy system 1 according to the present invention can supply a high frequency with small fluctuations in power to the acceleration tube 64 even when the acceleration tube 64 moves relative to the klystron 5. The fluctuation of the energy of the electron beam 57 can be reduced, and the fluctuation of the energy (energy distribution) of the therapeutic radiation 23 can be reduced. That is, the operation of the control device 7 is performed when the variation in transmission efficiency due to the movement of the therapeutic radiation irradiation device 16 is greater than the variation in transmission efficiency due to the variation in the temperature of the waveguide 8 (particularly, the rotary joint 75). Therefore, it is more necessary and useful for reducing fluctuations in transmission efficiency. As a result, the radiotherapy system 1 according to the present invention can control the dose of the therapeutic radiation 23 with higher accuracy.

  In another embodiment of the radiotherapy system according to the present invention, the control unit 103 in the above-described embodiment is replaced with another control unit. The control unit calculates a control amount corresponding to the combination of the turning angle, the traveling angle, the pan angle, and the tilt angle collected by the state collection unit 102 with reference to the control table 104, and the oscillation RF intensity of the klystron 5. Alternatively, the klystron 5 is controlled so that the klystron acceleration voltage or the klystron current matches the oscillation RF intensity or the klystron acceleration voltage or the klystron current indicated by the control amount.

  At this time, the operation of the control device 7 is when the variation in transmission efficiency due to the movement of the therapeutic radiation irradiation device 16 is greater than the variation in transmission efficiency due to the variation in the temperature of the waveguide 8 (particularly the rotary joint 75). Furthermore, it is useful for further reducing fluctuations in the transmission efficiency of the waveguide 8. Similar to the radiotherapy system 1, such a radiotherapy system can supply a high frequency with small power fluctuations to the accelerating tube 64, and the fluctuation in energy of the electron beam 57 generated by the accelerating tube 64 can be reduced. And the fluctuation of the energy (energy distribution) of the therapeutic radiation 23 can be reduced. Such a radiotherapy system does not need to include the transmission efficiency sensor 6-5, and can be manufactured at a lower cost.

  In still another embodiment of the radiotherapy system according to the present invention, the state collection unit 102 in the above-described embodiment is replaced with another state collection unit, and the control unit 103 is replaced with another control unit. The state collection unit collects state control signals transmitted from the radiotherapy apparatus control apparatus 2 to the turning drive apparatus 11, the travel drive apparatus, the pan axis drive apparatus, and the tilt axis drive apparatus from the radiotherapy apparatus control apparatus 2, Based on the control signal, the state of the waveguide 8 is calculated. That is, the state collection unit calculates a turning angle at which the O-ring 12 rotates about the rotation shaft 17 with respect to the base based on the state control signal. Based on the state control signal, the state collection unit further calculates a running angle at which the second cylinder portion 92 rotates about the rotation shaft 93 with respect to the first cylinder portion 91. The state collection unit further calculates a pan angle at which the therapeutic radiation irradiation device 16 rotates about the pan axis 21 with respect to the intermediate body 82 based on the state control signal. The state collection unit further calculates a tilt angle at which the intermediate body 82 rotates about the tilt axis 22 with respect to the irradiation apparatus support 81 based on the state control signal. The control unit refers to the control table 104, calculates a control amount corresponding to the combination of the turning angle, the traveling angle, the pan angle, and the tilt angle calculated by the state collection unit 102, and oscillates the RF intensity of the klystron 5. Alternatively, the klystron 5 is controlled so that the klystron acceleration voltage or the klystron current matches the oscillation RF intensity or the klystron acceleration voltage or the klystron current indicated by the control amount.

  At this time, the operation of the control device 7 is when the variation in transmission efficiency due to the movement of the therapeutic radiation irradiation device 16 is greater than the variation in transmission efficiency due to the variation in the temperature of the waveguide 8 (particularly the rotary joint 75). This is more necessary, and is useful for further reducing fluctuations in the transmission efficiency of the waveguide 8. Similar to the radiotherapy system 1, such a radiotherapy system can supply a high frequency with small power fluctuations to the accelerating tube 64, and the fluctuation in energy of the electron beam 57 generated by the accelerating tube 64 can be reduced. And the fluctuation of the energy (energy distribution) of the therapeutic radiation 23 can be reduced. Such a radiation therapy system does not need to further include a turning angle sensor 6-1, a traveling angle sensor 6-2, a pan angle sensor 6-3, a tilt angle sensor 6-4, and a transmission efficiency sensor 6-5. Can be manufactured at a lower cost.

  The klystron 5 can be replaced with another high-frequency source. Examples of the high frequency source include a magnetron and a multipolar tube. The magnetron generates a high frequency with a predetermined power by controlling a magnetron current. At this time, the control device 7 can reduce the fluctuation of the energy of the electron beam 57 and the fluctuation of the energy (energy distribution) of the therapeutic radiation 23 by controlling the magnetron current. In the multipolar tube, the oscillation RF intensity, the multipolar tube acceleration voltage, or the multipolar tube current is controlled to generate a high frequency of a predetermined power. At this time, the control device 7 controls the oscillation RF intensity, the multipolar tube acceleration voltage, or the multipolar tube current, thereby reducing the fluctuation of the energy of the electron beam 57 and the energy (energy distribution) of the therapeutic radiation 23. Variations can be reduced.

  The control table 104 can further associate a set of other states different from the shape of the waveguide by the waveguide 8 with the control amount 109. As the state, the temperature of each part of the waveguide 8 is exemplified. At this time, the control device 7 can control the klystron 5 based on the shape of the waveguide and its state to supply the acceleration tube 64 with a high frequency with less fluctuation in power than the radiation treatment system 1. The fluctuation of the energy of the electron beam 57 generated by the acceleration tube 64 can be reduced, and the fluctuation of the energy (energy distribution) of the therapeutic radiation 23 can be reduced.

  Note that the control table 104 can further associate only the set of rotation angles of the rotary joint 75 with the control amount 109 independently of the deformation of the flexible waveguides 74, 86, and 87. In general, a flexible waveguide has a sufficiently small variation in transmission efficiency due to deformation compared to a rotary joint. For this reason, the control device 7 controls the klystron 5 on the basis of the shape of the waveguide, so that the performance is slightly inferior to that of the radiotherapy system 1, but a high frequency with small fluctuations in power is supplied to the acceleration tube 64. The fluctuation of the energy of the electron beam 57 generated by the acceleration tube 64 can be reduced, and the fluctuation of the energy (energy distribution) of the therapeutic radiation 23 can be reduced.

  Still another embodiment of the radiotherapy system according to the present invention does not include the control device 7 in the above-described embodiment. In such a radiation therapy system, the fluctuation in transmission efficiency due to movement of the therapeutic radiation irradiation device 16 is sufficiently small, and the degree of fluctuation in transmission efficiency is sufficiently reduced by cooling the waveguide 8. It is preferable.

  The circulator 77 attenuates the high-frequency reflection that travels the waveguide 8 from the acceleration tube 64 toward the klystron 5 as compared to the high-frequency travel that travels the waveguide 8 from the klystron 5 toward the acceleration tube 64. The nonreciprocal circuit element can be replaced. As the non-reciprocal circuit element, an isolator is exemplified. The isolator can reduce the degree of fluctuation in transmission efficiency in the same manner as the circulator. Since the circulator has a larger heat removal capability than that of the isolator, it is preferable to apply the circulator to the radiotherapy system 1 according to the present invention.

  The rotary joint 75 can also be applied to an apparatus different from the radiation therapy system 1. Examples of the apparatus include a synchrotron radiation facility that emits synchrotron radiation, a nondestructive inspection apparatus, a sterilization apparatus, and a plasma processing apparatus that processes the surface of a substrate such as a semiconductor substrate or a liquid crystal substrate with plasma.

FIG. 1 is a block diagram showing an embodiment of a radiation therapy system according to the present invention. FIG. 2 is a perspective view showing the radiation therapy apparatus. FIG. 3 is a cross-sectional view showing a therapeutic radiation irradiation apparatus. FIG. 4 is a side view showing the waveguide. FIG. 5 is a front view showing the waveguide. FIG. 6 is a perspective view showing a swing mechanism and a waveguide. FIG. 7 is a perspective view showing the rotary joint. FIG. 8 is a cross-sectional view showing the rotary joint. FIG. 9 is a block diagram illustrating the control device. FIG. 10 is a diagram illustrating a control table. FIG. 11 is a graph showing the relationship between the rotation angle of the rotary joint and high-frequency transmission efficiency. FIG. 12 shows the relationship between the rotation angle of the rotary joint and the high-frequency transmission efficiency when the waveguide does not include a circulator, and the rotation angle and high-frequency of the rotary joint when the waveguide includes a circulator. It is a graph which shows the relationship with transmission efficiency. FIG. 13 is a graph showing the relationship between the rotation angle of the rotary joint and the high-frequency power output from the klystron. FIG. 14 is a graph showing the relationship between the rotation angle of the rotary joint and the electric power input to the acceleration tube.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1: Radiation therapy system 2: Radiation therapy apparatus control apparatus 3: Radiation therapy apparatus 5: Klystron 6: Sensor 6-1: Turning angle sensor 6-2: Running angle sensor 6-3: Pan angle sensor 6-4: Tilt angle Sensor 6-5: Transmission efficiency sensor 7: Control device 8: Waveguide 11: Turning drive device 12: O-ring 14: Traveling gantry 15: Swing mechanism 16: Radiation irradiation device for treatment 17: Rotating shaft 18: Rotating shaft 19: Isocenter 21: Pan axis 22: Tilt axis 23: Radiation for treatment 24: X-ray source for diagnosis 25: X-ray source for diagnosis 31: Sensor array 32: Sensor array 33: Sensor array 35: X-ray for diagnosis 36: Diagnostic X-ray 41: Couch 42: Couch drive device 43: Patient 51: Electron beam accelerator 52: X-ray target 53: Primary collimator 54: Flat Toning filter 55: Secondary collimator 56: Multi-leaf collimator 57: Electron beam 58: Virtual point source which is a point in the inside 59: Radiation 60: Radiation 61: Dosimeter 63: Electron beam generator 64: Acceleration tube 66 : Cathode 67: Grid 68: Multiple electrodes 69: Grid power supply 70: Cathode power supply 71: Fixed waveguide 72: Fixed waveguide 73: Fixed waveguide 74: Flexible waveguide 75: Rotary joint 76: Turntable 77: Circulator 81: Irradiation device support 82: Intermediate 84: Fixed waveguide 85: Fixed waveguide 86: Flexible waveguide 87: Flexible waveguide 91: First tube portion 92: Second tube portion 93 : Rotary shaft 95: Water-cooled tube 96: Water-cooled tube 97: Water-cooled tube 99: Clearance 101: Control database 102: Status collection unit 1 03: Control unit 104: Control table 105: Turning angle 106: Traveling angle 107: Pan angle 108: Tilt angle 109: Control amount

Claims (6)

A waveguide forming a waveguide for transmitting a high frequency from a high frequency source to an acceleration tube;
A cooler for cooling the waveguide,
The acceleration tube accelerates charged particles for generating therapeutic radiation using the high frequency. In claim 1,
The waveguide includes a rotary joint whose other end is rotatable with respect to one end;
The cooler is a radiotherapy system that cools the rotary joint. In claim 2,
The waveguide further includes a fixed waveguide adjacent to the rotary joint;
The cooler further cools the fixed waveguide. In either claim 2 or claim 3,
The radiotherapy system which further comprises the nonreciprocal circuit element interposed between the said rotary joint of the said waveguide, and the said acceleration tube. In any one of Claims 1-4,
A device for outputting the state of the waveguide;
A radiotherapy system further comprising: a control device that controls the high-frequency source based on the state so that predetermined power is supplied to the acceleration tube using the high-frequency. Forming a waveguide for transmitting a high frequency, and a rotary joint body in which the other end of the waveguide is rotatable with respect to one end of the waveguide;
A rotary joint comprising: a cooler for cooling the rotary joint body.

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