JP2009039219A - Charged particle beam irradiation system and charged particle beam irradiation method - Google Patents

Abstract

A charged particle beam irradiation system and a charged particle beam irradiation method capable of reducing the accuracy of the beam irradiation position while ensuring safety and shortening the adjustment time of an accelerator and a beam transport system. provide.
A charged particle beam generator 3 and an irradiation device 5 having scanning electromagnets 21A and 21B for deflecting the charged particle beam emitted from the charged particle beam generator 3 and scanning the scanning surface are provided. In the charged particle beam irradiation system, the second dose monitor 27 for detecting the irradiation amount in each of a plurality of divided areas obtained by dividing the scanning plane to be smaller than the beam cross-sectional area, and a beam having the same range on the scanning plane When the integrated dose is calculated for each of the divided areas when it is moved and the calculated integrated dose exceeds the allowable value stored in advance, the charged particle beam generator 3 applies the irradiation device. And an irradiation control device 6 for stopping the beam emission to 5.
[Selection] Figure 9

Description

  The present invention relates to a charged particle beam irradiation system and a charged particle beam irradiation method, and more particularly to a charged particle suitable for application to a particle beam therapy system that irradiates an affected area with a charged particle beam such as protons or carbon ions. The present invention relates to a beam irradiation system and a charged particle beam irradiation method.

  Radiotherapy is performed by a method of necrotizing tumor cells by irradiating the target tumor cells with radiation. X-rays and particle beams are used for this radiation. In the case of X-rays, the dose given near the body surface is the largest, and the dose given inside the body is attenuated. On the other hand, the particle beam is excellent in that the dose given immediately before stopping is the largest and the dose can be concentrated on the tumor region. Therefore, in recent years, particle beam therapy systems that use particle beams are becoming widespread.

  In particle beam therapy systems, in general, an accelerator that accelerates and emits a charged particle beam (particle beam) such as a proton beam or a carbon beam, a beam transport system that transports a charged particle beam emitted from the accelerator, and the beam And an irradiation device that is connected to a transport system and irradiates the affected area of a target patient with a charged particle beam. The irradiation apparatus must irradiate the beam so that the dose given to the affected area is higher than the surrounding area, and the influence on the normal tissue around the target must be minimized. That is, the charged particle beam emitted from the accelerator usually has a Gaussian dose distribution with a diameter of about 1 to 5 mm, and it is necessary to shape the irradiation region and dose distribution to match the target shape. is there. As an irradiation method for achieving such an object, a scatterer method and a scanning method are known (for example, see Non-Patent Document 1). The scatterer method is a method of shaping an irradiation region by expanding a beam in a radial direction with a scatterer and making a dose distribution uniform, and then cutting it with a collimator. The scanning method is a method of shaping an irradiation region having a uniform dose distribution by scanning a beam on a scanning plane perpendicular to the traveling direction with a scanning electromagnet.

  In the scanning type irradiation apparatus, the excitation current of the scanning electromagnet is changed to control the position on the scanning surface (irradiation position) of the beam. However, the position of the beam may be shifted due to various factors such as hysteresis of the electromagnet. Therefore, in order to cope with this, a beam position monitor for detecting the position of the beam, a storage device for storing the set position of the beam, a detection position of the beam detected by the beam position monitor, and a beam stored in the storage device. A configuration is proposed that includes an abnormality determination device that compares a set position and determines whether the error is within a predetermined allowable range (see, for example, Patent Document 1). In this prior art, for example, when the error of the beam position is larger than a predetermined allowable range, it is determined as abnormal and an interlock signal is output, which is provided between the synchrotron emission device (high frequency application device) and the high frequency power source. The opened / closed switch is opened to stop the beam emission from the synchrotron.

“REVIEW OF SCIENTIFIC INSTRUMENTS”, August 1993, Vol. 64, p. 2084-2089 2005-296162 (paragraph [0049] etc.)

However, there are the following problems in the above-described prior art.
The abnormality determination device compares the detected position of the beam detected by the beam position monitor with the set position of the beam stored in the storage device. Is output and the open / close switch is opened to stop the beam emission from the synchrotron. Thereby, erroneous irradiation is surely prevented and safety is ensured. However, on the other hand, if the beam position is strictly managed (in other words, if the predetermined allowable range is reduced), there is a problem that the adjustment time of the accelerator, the beam transport system, and the like becomes long.

  An object of the present invention is to provide a charged particle beam irradiation system and a charged particle beam that can relax the accuracy of the irradiation position of the beam while ensuring safety, and can shorten the adjustment time of the accelerator and the beam transport system. It is to provide an irradiation method.

  (1) In order to achieve the above object, the present invention provides a charged particle beam generator for accelerating and emitting a charged particle beam, and a scanning surface by deflecting the charged particle beam emitted from the charged particle beam generator. In a charged particle beam irradiation system comprising a scanning electromagnet that scans above and an irradiation device that irradiates an irradiation target with a charged particle beam that has passed through the scanning electromagnet so that the scanning plane is smaller than a beam cross-sectional area A detector for detecting an irradiation amount in each of the plurality of partitioned regions, and an integrated irradiation amount in each of the plurality of partitioned regions when a beam having the same range is irradiated while moving the position on the scanning plane. , Integrated dose calculation means for calculating based on the detection result of the detector, first storage means for storing a preset allowable value of the integrated dose, and the integrated dose When the integrated irradiation amount calculated by the calculating means is compared with the allowable value stored in the first storage means, and it is determined that the integrated irradiation amount exceeds the allowable value, the irradiation from the charged particle beam generator is performed. First interlocking means for stopping beam emission to the apparatus.

  (2) In the above (1), preferably, the first storage means stores an allowable value obtained by multiplying a target value of the integrated dose by a different allowable coefficient depending on the range of the beam.

  (3) In the above (1), preferably, the first storage means assumes a case where the same position on the scanning surface is irradiated with a beam having the same range divided into a plurality of times, An allowable value obtained by multiplying a target value of the integrated dose by a different allowable coefficient depending on the stage is stored.

  (4) To achieve the above object, the present invention provides a charged particle beam generator for accelerating and emitting a charged particle beam, and a scanning surface by deflecting the charged particle beam emitted from the charged particle beam generator. In a charged particle beam irradiation system comprising a scanning electromagnet that scans above and an irradiation device that irradiates an irradiation target with a charged particle beam that has passed through the scanning electromagnet so that the scanning plane is smaller than a beam cross-sectional area A detector for detecting an irradiation amount in each of the plurality of partitioned regions, and an integrated irradiation amount in each of the plurality of partitioned regions when a beam having the same range is irradiated while moving the position on the scanning plane. The integrated dose calculation means for calculating based on the detection result of the detector, and the dose in the same dose area composed of a plurality of divided areas having the same target value of the cumulative dose Uniformity calculation means for calculating the uniformity of the calculated dose based on the calculation result of the integrated dose calculation means, and a second memory for storing a preset allowable value of the uniformity of the integrated dose And the uniformity of the integrated dose calculated by the uniformity calculating means and the allowable value stored in the second storage means, and the uniformity of the integrated dose exceeds the allowable value And a second interlock means for stopping the emission of the beam from the charged particle beam generator to the irradiation device when it is determined that the charged particle beam generator has determined.

  (5) In the above (4), preferably, the second storage means stores an allowable value of the uniformity of the integrated dose that varies depending on the range of the beam.

  (6) In the above (4), preferably, the second storage means assumes a case where a beam having the same range is irradiated to the same irradiation position in a plurality of times, and different integrations are performed depending on the irradiation stage. An allowable value of the uniformity of the dose is stored.

  (7) In order to achieve the above object, the present invention irradiates a charged particle beam with an irradiation device having a scanning electromagnet that deflects the charged particle beam emitted from the charged particle beam generator and scans it on the scanning surface. In a charged particle beam irradiation method for irradiating a target, a beam having the same range is based on a detection result of a detector that detects an irradiation amount in each of a plurality of partitioned regions in which the scanning plane is partitioned to be smaller than a beam cross-sectional area. Is calculated by calculating the integrated dose in each of the plurality of divided areas when the position is irradiated on the scanning plane, and the calculated integrated dose is compared with the allowable value preset and stored in the storage means. When it is determined that the integrated irradiation amount exceeds the allowable value, the beam emission from the charged particle beam generator to the irradiation device is stopped.

  (8) In order to achieve the above object, the present invention irradiates a charged particle beam by an irradiation device having a scanning electromagnet that deflects the charged particle beam emitted from the charged particle beam generator and scans it on the scanning surface. In a charged particle beam irradiation method for irradiating a target, a beam having the same range is based on a detection result of a detector that detects an irradiation amount in each of a plurality of partitioned regions in which the scanning plane is partitioned to be smaller than a beam cross-sectional area. Is calculated by calculating the integrated dose in each of the plurality of partitioned areas when the position on the scanning plane is moved, and based on the calculation result, the plurality of partitioned areas having the same target value of the integrated dose Calculating the uniformity of the integrated dose in the same region of the dose, and comparing the calculated uniformity of the integrated dose with the allowable value preset and stored in the storage means, If the uniformity of the calculation dose is determined to have exceeded the allowable value, it stops the emission of the beam to the irradiation device from said charged particle beam generator.

  According to the present invention, the accuracy of the beam irradiation position can be relaxed while ensuring safety, and the adjustment time of the accelerator and the beam transport system can be shortened.

  Hereinafter, a particle beam therapy system according to a preferred embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram showing the overall configuration of the particle beam therapy system according to the first embodiment of the present invention.

  In FIG. 1, the particle beam therapy system irradiates an affected part 2a (see FIG. 2 described later) of a patient 2 fixed to a treatment bed 1 with a charged particle beam (particle beam) such as a proton beam or a carbon beam. A charged particle beam generator 3, a beam transport system 4 for transporting a charged particle beam emitted from the charged particle beam generator 3, and a charged particle beam connected to the beam transport system 4. Is irradiated to the affected area 2a of the patient 2. Also, an acceleration / transport control device (not shown) for controlling the charged particle beam generator 3 and the beam transport system 4, an irradiation control device 6 for controlling the irradiation device 5, and treatment plan data (details will be described later) are created. A treatment planning device 7, a central control device 8 that controls the acceleration / transport control device and the irradiation control device 6, and a display device 9 connected to the irradiation control device 6 and the central control device 8. .

  The charged particle beam generator 3 includes an ion source 10, a pre-accelerator 11 (for example, a linear accelerator) that accelerates charged particles generated from the ion source 10, and a synchrotron that further accelerates the charged particle beam from the pre-accelerator 11. 12 (in place of this synchrotron, another accelerator such as a cyclotron may be used). The synchrotron 12 includes a plurality of deflection electromagnets 13 and a plurality of quadrupole electromagnets (not shown) for rotating the charged particle beam, an acceleration device 14 for accelerating the rotating charged particle beam, and a deflector 15 for emitting the charged particle beam. And an emission device 16 for emitting light from the light source. The acceleration device 14 generates a high-frequency electromagnetic field in a high-frequency accelerating cavity (not shown) in synchronization with the circulation cycle of the beam, and accelerates the charged particle beam. As a result, the beam energy is increased to a set value (for example, about 70 to 250 MeV).

  The emission device 16 includes, for example, a high frequency application electrode (not shown), and the high frequency application electrode is connected to a high frequency power source 19 via an interlock switch 17 and an emission switch 18. The interlock switch 17 is normally in a closed state. For example, when the extraction switch 18 is switched to a closed state in response to a beam extraction start signal from the irradiation control device 6, the extraction device 16 receives the high-frequency power from the high-frequency power source 19. Is applied to apply a high frequency to the charged particle beam. As a result, the charged particle beam leaves the circular orbit and is emitted from the extraction deflector 15. On the other hand, when the interlock switch 17 or the emission switch 18 is in the open state, the charged particle beam is not emitted.

  The beam transport system 4 has a plurality of deflection electromagnets and a plurality of quadrupole electromagnets, and transports the charged particle beam emitted from the synchrotron 12 to the irradiation device 5.

  The irradiation device 5 is installed in a rotating gantry (not shown) together with a beam path 20 that is a part of the beam transport system 4, and the rotating gantry rotates around the patient 2 to irradiate the beam from an arbitrary direction. It is possible. Further, the irradiation device 5 in the present embodiment is a method of irradiating a charged particle beam with a scatterer while expanding a radial dimension while scanning a charged particle beam on a scanning plane perpendicular to the traveling direction, in other words, scanning. An irradiation method (called a uniform scanning method) located between the method and the scatterer method is employed. The configuration of such an irradiation apparatus 5 will be described with reference to FIG.

  FIG. 2 is a schematic diagram showing the configuration of the irradiation device 5 in this embodiment together with the irradiation control device 6.

  In FIG. 2, the irradiation device 5 includes scanning electromagnets 21A and 21B, a scatterer 22, a ridge filter 23, a range shifter 24, a position monitor 25, a first dose in the order along the beam traveling direction (downward in FIG. 2). A monitor 26, a second dose monitor 27, a collimator 28, and a bolus 29 are provided.

  The scanning electromagnets 21A and 21B are connected to the scanning electromagnet power supplies 30A and 30B, respectively, and a power supply control device 31 that controls the supply current from the scanning electromagnet power supplies 30A and 30B to the scanning electromagnets 21A and 21B is provided. . The power supply control device 31 controls the supply currents of the scanning electromagnets 21A and 21B in accordance with the command signal from the irradiation control device 6, thereby controlling the excitation magnetic fields of the scanning electromagnets 21A and 21B, respectively. By the excitation magnetic fields of the scanning electromagnets 21A and 21B controlled in this way, the charged particle beam is perpendicular to the traveling direction and orthogonal to each other in the X direction (left and right direction in FIG. 2) and Y direction (perpendicular to the paper surface in FIG. 2). Are deflected in the direction) and scanned.

  The scatterer 22 is composed of a plate member made of a material with a small energy loss with respect to the amount of beam scattering (specifically, a substance having a large atomic number such as tungsten), and the dose distribution in the radial direction of the beam is a Gaussian distribution. However, the beam is expanded in the radial direction. Since the amount of beam scattering by the scatterer 24 depends on the beam energy, the diameter of the beam cannot be made substantially the same unless the thickness of the scatterer 24 is changed according to the beam energy. Therefore, although not shown in FIG. 2 for the sake of convenience, a turntable on which a plurality of scatterers 22 having different thicknesses are mounted is provided, and the turntable is driven to rotate in response to a command signal from the irradiation control device 6. A scatterer 22 selected in accordance with the energy is arranged at a beam passing position.

  The ridge filter 23 is a so-called enlarged Bragg peak forming device that expands the energy distribution width of the beam and uniformly expands the dose distribution in the depth direction (vertical direction in FIG. 2) of the affected part 2a in the beam. The ridge filter 23 has a plurality of wedge-shaped structures, and the thickness dimension through which the beam is transmitted differs depending on the beam incident position. Thereby, since the amount of energy loss differs according to the beam incident position, a beam having a plurality of energy components is formed. As a result, when the affected part 2a is irradiated, a plurality of Bragg peaks having different depths are formed, and as a whole, a uniform dose distribution is formed in the depth direction of the affected part 2a.

  The range shifter 24 is composed of a plurality of absorbers made of a material having a small beam scattering amount with respect to energy loss (specifically, a substance having a small atomic number such as a resin) having different thicknesses, and an absorber drive for moving these absorbers. It consists of a device. Then, an absorber is selected in accordance with a command signal from the irradiation control device 6 and moved to a beam passing position, so that the beam energy is attenuated to adjust the range (depth of arrival).

  The collimator 28 is constituted by a shield that shields the charged particle beam, and a through-hole corresponding to the shape of the affected part 2a in the lateral direction (in other words, the direction perpendicular to the beam traveling direction) is formed in the shield. . Thereby, the irradiation range of the charged particle beam is shaped according to the shape in the lateral direction of the affected part 2a.

  The bolus 29 is formed by excavating a block body made of, for example, a resin, and the thickness dimension changes according to the beam incident position. Thereby, the beam range is adjusted for each beam incident position, and the arrival depth of the charged particle beam is adjusted to the depth shape of the affected part 2a.

  Returning to FIG. 1 described above, the treatment planning apparatus 7 treats treatment plan data (specifically, for example, the shape of the affected part 2a, the irradiation direction, a plurality of layers obtained by dividing the affected part 2a in the depth direction, and the shape of each layer (irradiation field). ) Etc. are created and output to the central control unit 8. In the particle beam therapy system of this embodiment, spot irradiation control of a beam (specifically, spot irradiation with a fixed irradiation position is performed, and spot irradiation is stopped when the beam irradiation amount at the irradiation position reaches a target value. Thereafter, control for moving the irradiation position in a state where the beam irradiation is interrupted) is performed. Therefore, the treatment plan data also includes information such as the spot irradiation position in each layer, the irradiation order, and the target value of the beam irradiation amount at each spot irradiation position. Details of such a treatment plan will be described with reference to FIGS.

  First, a method for forming a uniform dose distribution in the depth direction will be described. In addition to the method using the ridge filter described above, the uniform distribution can be formed by dividing the affected part 2a in the depth direction and sequentially irradiating a beam having a Bragg peak at a position corresponding to each depth. There are ways to go. In this case, irradiation with beams having different Bragg peak depths is realized by adjusting the energy of the accelerator and the thickness of the range shifter described below. In the uniform scanning method, which is the irradiation method of the present embodiment, either method is possible, but in the future, the description will proceed based on the latter method. However, the present invention can be similarly applied to the case where a uniform dose distribution is formed in the depth direction by the ridge filter.

  FIG. 3 is a diagram schematically showing a dose distribution in the depth direction of the affected part 2a in the beam. As shown by the solid line in FIG. 3, the dose distribution in the depth direction of the affected part 2a in the beam forms a Bragg peak at a depth position corresponding to the range of the beam (in other words, beam energy). Therefore, when a plurality of charged particle beams having different ranges (six examples are shown in FIG. 3) are superimposed, a distribution (illustrated by a dotted line in FIG. 3) in which the dose becomes uniform in the depth direction of the affected part 2a is formed. It is possible. Based on such a viewpoint, the treatment planning device 7 sets a beam range interval (preferably about twice the Bragg peak width), and based on this, a plurality of layers that divide the affected part 2a in the depth direction. Set.

  In addition, since the charged particle beam gives a dose to a position shallower than the Bragg peak position, the irradiation order is usually set so that irradiation is performed from a deep layer. Further, in order to form a distribution in which the dose is uniform in the depth direction of the affected area 2a, as shown in FIG. 3, the irradiation amount of the beam having the short range must be made smaller than the irradiation amount of the beam having the long range. I must. Based on such a viewpoint, the irradiation amount of the beam is set.

  FIG. 4 is a diagram schematically showing a dose distribution in the radial direction of the beam. As shown by the solid line in FIG. 4, the dose distribution in the radial direction of the beam is a Gaussian distribution. Therefore, by superimposing a plurality of charged particle beams having different spot irradiation positions (four examples in FIG. 4), it is possible to form a distribution (shown by a dotted line in FIG. 4) in which the dose becomes uniform. Based on such a viewpoint, the treatment planning device 7 sets the beam diameter and the position interval of the spot irradiation (preferably between about 1 to 2 times the standard deviation of the Gaussian distribution) and based on this. A spot irradiation position (in other words, a center position of spot irradiation) in each layer is set. Specifically, the spot irradiation positions Si (i = 1, 2,...) May be arranged in a lattice pattern, for example, as shown in FIG. For example, as shown in FIG. 5B, the spot irradiation positions Sj (j = 1, 2,...) May be arranged in a triangular shape. Alternatively, although not shown, the spot irradiation positions may be arranged without making the spot irradiation position interval constant. Thereafter, the irradiation order and the target value of the irradiation amount at each spot irradiation position are set.

  Returning to FIG. 1, the central control device 8 stores the treatment plan data input from the treatment plan device 7 in the memory 32, and creates operation control data based on the treatment plan data and stores it in the memory 32. . The operation control data includes not only information calculated based on information included in the treatment plan data but also information previously set and stored in the memory 32. The central control device 8 outputs the operation control data stored in the memory 32 to the acceleration / transport control device and the irradiation control device 6 in response to a treatment start command from the operator, and the acceleration / transport control device and The irradiation control device 6 is controlled in an integrated manner.

  The acceleration / transport control device operates the operation control data input from the central control device 8 (specifically, a set value of the beam energy corresponding to each layer obtained by dividing the affected part 2a in the depth direction, and a setting value for this beam energy). Data including control parameters such as the excitation current of the electromagnet are stored in an internal memory, and the charged particle beam generator 3 and the beam transport system 4 are controlled based on the operation control data.

  The irradiation control device 6 receives the operation control data input from the central control device 8 (specifically, the combination of the absorber of the range shifter 24 corresponding to each layer obtained by dividing the affected part 2a in the depth direction and the scatterer corresponding to the beam energy. 22 types, excitation current patterns of the scanning electromagnets 21A and 21B corresponding to the spot irradiation position and irradiation order in each layer, target values of the irradiation dose at each spot irradiation position, and information on the irradiation position and allowable dose value, etc. Is stored in a memory 33 (see FIG. 6 described later), and the irradiation device 5 and the like are controlled based on the operation control data.

  More specifically, as a first function (spot irradiation control function), the irradiation control device 6 first controls the excitation magnetic field of the operation electromagnets 21A and 21B via the power supply control device 31 to fix the beam irradiation position. Thereafter, a beam extraction start signal is output to switch the extraction switch 18 to the closed state, and the charged particle beam is emitted from the charged particle beam generation device 3 to the irradiation device 5 to start spot irradiation to the affected part 2a. Then, it is determined whether or not the beam irradiation amount in the single spot irradiation detected by the first dose monitor 26 has reached the target value, and when the beam irradiation amount has reached the target value, a beam extraction stop signal is output. The extraction switch 18 is switched to the open state, the beam emission from the charged particle beam generator 3 to the irradiation device 5 is interrupted, and the spot irradiation to the affected part 2a is stopped. Thereafter, the spot irradiation position is changed in a state where the beam irradiation to the affected part 2a is interrupted.

  Further, the irradiation control device 6 outputs an interlock signal according to the detection results of the position monitor 25, the first dose monitor 26, and the second dose monitor 27 as the second function (interlock control function). It has become.

  FIG. 6 is a block diagram showing a functional configuration related to the interlock control of the irradiation control device 6.

  In FIG. 6, the irradiation control device 6 includes a memory 33 that stores the above-described operation control data and the like, and an input unit 34 that inputs detection signals from the position monitor 25, the first dose monitor 26, and the second dose monitor 27. And an arithmetic control unit 35 for performing predetermined arithmetic processing based on detection signals from the position monitor 25, the first dose monitor 26, and the second dose monitor 27, and an interlock signal generated by the arithmetic control unit 35. An output unit 37 that outputs to the interlock device 36 and outputs a display signal to the display device 9 is provided. The interlock device 36 switches the interlock switch 17 to an open state in response to an interlock signal from the irradiation control device 6, and interrupts beam emission from the charged particle beam generator 3 to the irradiation device 5. (See FIG. 1 above).

  The calculation control unit 35 of the irradiation controller 6 calculates a beam irradiation position deviation (difference from the target value) based on the detection signal from the position monitor 25, and the calculated irradiation position deviation is stored in the memory 33. For example, when it is determined that the deviation of the irradiation position exceeds the allowable value, an interlock signal and a display signal are output from the output unit 37.

  The first dose monitor 26 can continuously detect the irradiation amount of the entire beam and outputs the detection signal. Then, the calculation control unit 35 calculates the beam irradiation amount in the single spot irradiation based on the detection signal from the first dose monitor 26, and whether the calculated beam irradiation amount exceeds the allowable value stored in the memory 33. For example, when it is determined that the beam irradiation amount has exceeded the allowable value, an interlock signal and a display signal are output from the output unit 37.

  The second dose monitor 27, which is the main part of the present invention, has a plurality of partitioned areas Pi (i = 1, 1) partitioned by the scanning electromagnets 21A and 21B so that the scanning surface A of the beam is smaller than the cross-sectional area B of the beam. 2,... Can be continuously detected (see FIG. 7), and the detection signal is output. Then, the calculation control unit 35 detects from the second dose monitor 27 while irradiating the same layer of the affected area 2a (in other words, while irradiating the same range of the beam while moving the position on the scanning surface). Based on the signal, the integrated dose in each of the plurality of partitioned areas Pi corresponding to the irradiation field is calculated. Specifically, a plurality of corresponding partitioned areas are set with reference to the irradiation field stored in the memory 33, and detection values (count values) are respectively integrated in the set partitioned areas. Since the dose distribution in the radial direction of the beam is a Gaussian distribution, the detected value is relatively large in the partitioned area located near the center of the beam, and the detected value is relatively small in the partitioned area far from the center of the beam. It has become. Then, the calculation control unit 35 determines whether or not the calculated integrated dose exceeds the allowable value stored in the memory 33. For example, when it is determined that the integrated dose exceeds the allowable value, an interlock signal and a display are displayed. A signal is output from the output unit 37.

  FIG. 8 is a flowchart showing the control processing content of spot irradiation control in the particle beam therapy system of this embodiment. FIG. 9 is a flowchart showing a detailed procedure of the interlock control process in step 130 in FIG.

  First, in step 100, the range of the beam corresponding to the first layer obtained by dividing the affected area 2 in the depth direction is set. The acceleration / transport control device controls the charged particle beam generator 3 to accelerate the charged particle beam to increase the beam energy to a set value, and prepares a beam transport system 4 corresponding to the set value of the beam energy. . In addition, the irradiation control device 6 selects the type of the scatterer 22 in the irradiation device 5 to adjust the beam size, and controls the combination of the absorbers of the range shifter 24 to adjust the range of the beam. Yes. Thereafter, the process proceeds to step 110, where the irradiation control device 6 controls the excitation magnetic fields of the scanning electromagnets 21A, 21B via the power supply control device 31 to fix the first spot irradiation position.

  Then, the process proceeds to step 120, where the irradiation control device 6 outputs a beam extraction start signal to switch the extraction switch 18 to the closed state, and emits a charged particle beam from the charged particle beam generator 3 to the irradiation device 5, Spot irradiation to the affected part 2a is started. At this time, the irradiation control device 6 calculates the deviation of the irradiation position of the beam based on the detection signal from the position monitor 25, and calculates the beam irradiation amount in a single spot irradiation based on the detection signal from the first dose monitor 26. Based on the detection signal from the second dose monitor 27, the integrated dose in each of the plurality of partitioned areas Pi is calculated. And it progresses to step 130 and the irradiation control apparatus 6 transfers to an interlock control process based on those calculation results.

  In the interlock control process, in step 131, it is determined whether or not the calculated deviation of the beam irradiation position exceeds the allowable value stored in the memory 33. For example, when the deviation of the beam irradiation position exceeds the allowable value, the determination at step 131 is satisfied, and the routine proceeds to step 132. In step 132, an interlock signal is output to the interlock device 36, the interlock switch 17 is switched to the open state, beam emission from the charged particle beam generator 3 to the irradiation device 5 is interrupted, and the affected part 2a is output. Stop beam irradiation. In addition, a display signal is output to the display device 9, and a display for notifying that the beam irradiation has been stopped is performed. On the other hand, for example, when the deviation of the beam irradiation position is less than the allowable value, the determination in step 131 is not satisfied, and the routine proceeds to step 133.

  In step 133, it is determined whether or not the integrated dose in each of the calculated plurality of partitioned areas Pi exceeds the allowable value stored in the memory 33. For example, when the integrated irradiation dose exceeds the allowable value, the determination in step 133 is satisfied, the process proceeds to step 132 described above, the same procedure is performed, and the beam irradiation to the affected area 2a is stopped. On the other hand, for example, when the integrated dose is less than the allowable value, the determination at step 133 is not satisfied, and the routine proceeds to step 134.

  In step 134, it is determined whether or not the calculated beam irradiation amount in the single spot irradiation exceeds the allowable value stored in the memory 33. For example, when the beam irradiation amount in the single spot irradiation exceeds the allowable value, the determination in step 134 is satisfied, the process proceeds to step 132 described above, and the same procedure is performed to stop the beam irradiation to the affected part 2a. . On the other hand, for example, if the beam irradiation amount in the single spot irradiation is less than the allowable value, the determination in step 134 is not satisfied, the interlock control process in step 130 is terminated, and the process proceeds to step 140.

  In step 140, the irradiation control device 6 determines whether or not the calculated beam irradiation amount in the single spot irradiation has reached the target value stored in the memory 33. For example, when the beam irradiation amount in the single spot irradiation does not reach the target value, the process returns to the above step 120 and the same procedure is repeated. On the other hand, for example, when the beam irradiation amount in the single spot irradiation reaches the target value, the process proceeds to step 150. In step 150, a beam extraction stop signal is output and the extraction switch 18 is switched to the open state, the beam emission from the charged particle beam generator 3 to the irradiation device 5 is interrupted, and the spot irradiation to the affected area 2a is stopped. .

  In step 160, it is determined whether there is another beam to be irradiated with the same range, that is, whether there is another spot irradiation position in the same layer of the affected area 2a. Generally, since there are other spot irradiation positions at first, the determination in step 160 is satisfied, and the process returns to step 110 described above. In step 110, the irradiation control device 6 controls the excitation magnetic fields of the scanning electromagnets 21 </ b> A and 21 </ b> B via the power supply control device 31 and fixes them at the next spot irradiation position. Thereafter, the above-described steps 120 to 150 are performed. At this time, the irradiation controller 6 newly calculates the deviation of the irradiation position of the beam and the beam irradiation amount in the single spot irradiation, and calculates the integrated irradiation amount in each of the plurality of divided areas Pi from the previous integration. Calculate while adding to the dose. Then, the procedures of Steps 110 to 150 are repeated, and when the last irradiation spot is completed in the same layer of the affected part 2a, the determination of Step 160 is not satisfied, and the process proceeds to Step 170.

  In step 170, it is determined whether there is another beam to be irradiated with a different range, that is, whether there is another layer to be irradiated in the affected area 2a. Generally, since there are other layers to be irradiated initially, the determination in step 170 is satisfied and the process returns to step 100 described above. Then, the above-described steps 100 to 160 are repeated, and when the irradiation of the last layer is completed, the determination of step 170 is satisfied, and the irradiation to the affected area 2a is completed.

  Note that, in the above, the second dose monitor 27 constitutes a detector that detects an irradiation amount in each of a plurality of partitioned areas in which the scanning plane described in the claims is partitioned so as to be smaller than the beam cross-sectional area. Further, the irradiation control device 6 calculates the integrated irradiation amount in each of the plurality of partitioned regions when the beam having the same range is irradiated while moving the position on the scanning plane based on the detection result of the detector. The first storage means that constitutes the dose calculating means and that stores the preset allowable value of the accumulated dose, and that is the first dose and the accumulated dose calculated by the accumulated dose calculation means. The first interlock means for stopping the beam emission from the charged particle beam generator to the irradiation apparatus when it is determined that the integrated dose exceeds the allowable value by comparing with the allowable value stored in the means. .

  As described above, in the present embodiment, the second dose monitor 27 that detects the irradiation amount in each of the plurality of partitioned areas Pi partitioned so that the scanning plane is smaller than the beam cross-sectional area is provided. Based on the detection result of the second dose monitor 27, the integrated dose in each of the plurality of partitioned regions Pi when the beam having the same range is irradiated while moving the position on the scanning plane is calculated. Then, the irradiation control device 6 compares the calculated integrated dose with the preset value stored and determines that the integrated dose exceeds the allowable value, and then, from the charged particle beam generator 3 to the irradiation device 5. Stops beam emission to (interlock). As a result, safety can be ensured, and the accuracy of the beam irradiation position, which is another interlock operating condition, can be relaxed. As a result, the adjustment time of the synchrotron 12 and the beam transport system 4 for ensuring the accuracy of the irradiation position can be shortened.

  Although not specifically described in the above-described embodiment, the central controller 8 multiplies the target value of the integrated dose by the allowable value of the integrated dose, for example, a different allowable coefficient depending on the range of the beam. It may be set and stored as a value. That is, for example, as shown in FIG. 3 described above, when the irradiation amount increases as the range of the beam becomes longer, the irradiation amount applied to the affected part 2a is dominated by the beam having a longer range, because the beam having the longer range is dominant. Since the influence becomes low, the above-described tolerance coefficient may be set to increase as the beam range becomes shorter. Also, for example, when irradiating the same spot irradiation position multiple times to the same spot irradiation position, the target value of the integrated dose is multiplied by the allowable value of the integrated dose and the different allowable coefficient depending on the number of times of irradiation. It may be set and stored as a value. That is, since the allowable value for the integrated dose at the initial stage or during the intermediate stage can be set to be relatively larger than the allowable value for the integrated dose at the final stage, the above-described allowable coefficient is increased as the initial stage is reached. It may be set. In these cases, the same effect as described above can be obtained.

  A second embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the degree of uniformity of the integrated dose is calculated, and the interlock is operated based on this. In the present embodiment, illustration and description of parts equivalent to those in the first embodiment are omitted as appropriate.

  In the present embodiment, the central control device 8 plans to irradiate the same spot irradiation position with a beam having the same range in a plurality of times, and sets the target of the beam irradiation amount for each stage of the number of irradiation times at each spot irradiation position. A value and its allowable value are set, and operation control data including such information is stored in the memory 32. The irradiation control device 6A stores the operation control data input from the central control device 8 in the memory 33, and controls the irradiation device 5 and the like based on the operation control data.

  Further, the irradiation control device 6A detects from the second dose monitor 27 while irradiating the same layer of the affected part 2a with a beam (in other words, irradiating a beam having the same range while moving the position on the scanning surface). Based on the signal, the integrated dose in each of the plurality of partitioned areas Pi corresponding to the irradiation field is calculated, and the integrated dose in the same dose range composed of the plurality of partitioned areas having the same target value of the integrated dose is calculated. Uniformity is calculated. Then, it is determined whether or not the calculated uniformity of the integrated dose exceeds the allowable value stored in the memory 33 (this allowable value is included in the operation control data created by the central control device 8). For example, when it is determined that the uniformity of the integrated dose exceeds an allowable value, an interlock signal and a display signal are output from the output unit 37.

  FIG. 10 is a flowchart showing the control processing content of the spot irradiation control in the particle beam therapy system of this embodiment. FIG. 11 is a flowchart showing a detailed procedure of the first interlock control process of step 240 in FIG. 10, and FIG. 12 shows a detailed procedure of the second interlock control process of step 280 in FIG. It is a flowchart.

  First, in step 200, the range of the beam corresponding to the first layer obtained by dividing the affected part 2 in the depth direction is set. The acceleration / transport control device controls the charged particle beam generator 3 to accelerate the charged particle beam to increase the beam energy to a set value, and prepares a beam transport system 4 corresponding to the set value of the beam energy. . Further, the irradiation control device 6A adjusts the beam size by selecting the type of the scatterer 22 in the irradiation device 5, and controls the combination of the absorbers of the range shifter 24 to adjust the range of the beam. Yes. In step 210, the irradiation control device 6A initially sets the irradiation number stage flag to i = 1. In step 220, the excitation magnetic field of the scanning electromagnets 21A and 21B is controlled via the power supply control device 31 to fix the first spot irradiation position.

  Then, in step 230, the irradiation control device 6A outputs a beam extraction start signal to switch the extraction switch 18 to the closed state, and causes the charged particle beam generator 3 to emit the charged particle beam to the irradiation device 5, Spot irradiation to the affected part 2a is started. At this time, the irradiation control device 6A calculates the deviation of the irradiation position of the beam based on the detection signal from the position monitor 25, and calculates the beam irradiation amount in the single spot irradiation based on the detection signal from the first dose monitor 26. Based on the detection signal from the second dose monitor 27, the integrated dose in each of the plurality of partitioned areas Pi is calculated. And it progresses to step 240 and 6 A of irradiation control apparatuses move to a 1st interlock control process.

  In the first interlock control process, in step 241, it is determined whether or not the calculated deviation of the beam irradiation position exceeds the allowable value stored in the memory 33. For example, if the deviation of the beam irradiation position exceeds the allowable value, the determination in step 241 is satisfied, and the routine proceeds to step 242. In step 242, an interlock signal is output to the interlock device 36, the interlock switch 17 is switched to an open state, beam emission from the charged particle beam generator 3 to the irradiation device 5 is interrupted, and Stop beam irradiation. In addition, a display signal is output to the display device 9, and a display for notifying that the beam irradiation has been stopped is performed. On the other hand, for example, when the deviation of the beam irradiation position is less than the allowable value, the determination in step 241 is not satisfied, and the routine proceeds to step 243.

  In step 243, it is determined whether or not the calculated beam irradiation amount in the single spot irradiation exceeds the allowable value stored in the memory 33. For example, when the beam irradiation amount in the single spot irradiation exceeds the allowable value, the determination in step 243 is satisfied, the process proceeds to step 242 described above, and the same procedure is performed to stop the beam irradiation to the affected part 2a. . On the other hand, for example, when the beam irradiation amount in single spot irradiation is less than the allowable value, the determination in step 243 is not satisfied, the interlock control processing in step 240 is terminated, and the routine proceeds to step 250.

  In step 250, the irradiation controller 6 </ b> A determines whether the calculated beam irradiation amount in the single spot irradiation has reached the target value stored in the memory 33. For example, when the beam irradiation amount in the single spot irradiation reaches the target value, the process returns to the above-described step 230 and the same procedure is repeated. On the other hand, for example, when the beam irradiation amount in the single spot irradiation reaches the target value, the process proceeds to step 260. In step 260, a beam extraction stop signal is output and the extraction switch 18 is switched to the open state, the beam emission from the charged particle beam generation device 3 to the irradiation device 5 is interrupted, and the spot irradiation to the affected area 2a is stopped. .

  Then, the process proceeds to step 270. Since i = 1 at first, whether there is another beam to be irradiated for the first time in the same range, that is, another spot irradiation position to be irradiated for the first time in the same layer of the affected area 2a. Determine if there is any. Generally, since there are other spot irradiation positions at first, the determination in step 270 is satisfied, and the process returns to step 220 described above. In step 220, the irradiation control device 6A controls the excitation magnetic field of the scanning electromagnets 21A and 21B via the power supply control device 31, and fixes it to the next spot irradiation position. Thereafter, the steps 230 to 260 described above are performed. At this time, the irradiation control device 6A newly calculates the deviation of the irradiation position of the beam and the beam irradiation amount in the single spot irradiation, and calculates the integrated irradiation amount in each of the plurality of divided areas Pi from the previous integration. Calculate while adding to the dose. Then, when the procedure of steps 220 to 260 is repeatedly performed and the first irradiation spot is completed for the first time in the same layer of the affected part 2a, the determination of step 270 is not satisfied, the process proceeds to step 280, and the irradiation control device 6A Then, the process proceeds to the second interlock control process.

  In the second interlock control process, in step 281, a plurality of corresponding section areas are set with reference to the same irradiation amount area stored in the memory 33, and the integrated irradiation dose is uniform in the set plurality of section areas. The degree (specifically, for example, a value obtained by dividing the difference between the maximum value and the minimum value of the integrated dose by the target value of the integrated dose) is calculated. Then, it is determined whether or not the calculated uniformity of the integrated dose exceeds the allowable value stored in the memory 33. For example, when the uniformity of the integrated dose exceeds the allowable value, the determination at step 281 is satisfied, and the routine proceeds to step 282. In step 282, as in step 242 described above, an interlock signal is output to the interlock device 36, the interlock switch 17 is switched to the open state, and beam emission from the charged particle beam generator 3 to the irradiation device 5 is interrupted. Then, the beam irradiation to the affected part 2a is stopped. In addition, a display signal is output to the display device 9, and a display for notifying that the beam irradiation has been stopped is performed. On the other hand, for example, if the uniformity of the integrated dose exceeds the allowable value, the determination in step 281 is not satisfied, the second interlock control process in step 280 is terminated, and the process proceeds to step 290.

  In step 290, it is determined whether i = n (n: final irradiation frequency stage). Since i = 1 at first, the determination in step 290 is not satisfied, and the routine goes to step 300. In step 300, i = i + 1 is calculated. Then, when the steps 230 to 300 described above are repeated and the last spot irradiation in the final irradiation frequency stage is completed, the determination in step 290 is satisfied, and the routine proceeds to step 310.

  In step 310, it is determined whether there is another beam to be irradiated with a different range, that is, whether there is another layer to be irradiated in the affected area 2a. Generally, because there are other layers to be irradiated initially, the determination of step 310 is satisfied and the process returns to step 200 described above. Then, when the steps 200 to 300 described above are repeated and the irradiation of the last layer is completed, the determination in step 310 is satisfied and the irradiation to the affected area 2a is completed.

  In the above description, the irradiation control device 6A calculates the integrated irradiation amount in each of the plurality of partitioned regions when the beam having the same range as claimed in the claims is irradiated while moving the position on the scanning plane. The integrated dose calculation means for calculating the integrated dose in the same dose range composed of a plurality of divided areas having the same target value for the total dose is configured as the integrated dose calculation means for calculating based on the detection result. Uniformity calculation means for calculating based on the calculation result of the calculation means, and second storage means for storing a preset allowable value of the uniformity of the integrated dose are configured, and uniform When the uniformity of the integrated dose calculated by the degree calculation means is compared with the allowable value stored in the second storage means, and it is determined that the uniformity of the integrated dose exceeds the allowable value, Beam output from particle beam generator to irradiation device Constituting the second interlocking means for stopping the.

  As described above, in the present embodiment, the irradiation control device 6 is based on the detection result of the second dose monitor 27, and a plurality of divided regions when the beam having the same range is irradiated while moving the position on the scanning plane. The integrated dose in each Pi is calculated, and the uniformity of the integrated dose in the same dose range composed of a plurality of partitioned regions having the same target value of the calculated dose is calculated. Then, the irradiation control device 6 compares the calculated uniformity of the integrated dose with an allowable value that is set and stored in advance, and determines that the uniformity of the integrated dose exceeds the allowable value. Beam emission from the beam generator 3 to the irradiation device 5 is stopped (interlock). As a result, safety can be ensured, and the accuracy of the beam irradiation position, which is another interlock operating condition, can be relaxed. As a result, the adjustment time of the synchrotron 12 and the beam transport system 4 for ensuring the accuracy of the irradiation position can be shortened.

  In the second embodiment, as the degree of uniformity of the integrated dose, a value obtained by dividing the difference between the maximum value and the minimum value of the integrated dose in the same dose range by the target value of the integrated dose is calculated. The case has been described as an example, but is not limited thereto. That is, for example, the standard deviation of the integrated dose in the same dose range may be calculated as the uniformity of the integrated dose. In this case, the same effect as described above can be obtained.

  Although not specifically described in the second embodiment, the central control unit 8 may set and store an allowable value of the uniformity of the integrated dose that varies depending on, for example, the range of the beam. Good. That is, for example, as shown in FIG. 3 described above, when the irradiation amount increases as the range of the beam becomes longer, the irradiation amount applied to the affected part 2a is dominated by the beam with a longer range, which is dominant. Since the influence becomes low, the above-described allowable value may be set to increase as the beam range becomes shorter. In addition, for example, when a beam having the same range is irradiated to the same spot irradiation position in a plurality of times, an allowable value for the uniformity of different integrated doses may be set and stored depending on the stage of the number of times of irradiation. Good. That is, since the allowable value for the integrated dose at the initial stage or during the intermediate stage can be set to be relatively larger than the allowable value for the integrated dose at the final stage, the above-described allowable value is increased as the initial stage is reached. It may be set. In these cases, the same effect as described above can be obtained.

  In the first embodiment, the interlock is activated when the integrated dose of the plurality of partitioned areas Pi exceeds the allowable value. In the second embodiment, the integrated irradiation in the same dose range is used. Although the case where the interlock is operated when the uniformity of the quantity exceeds the allowable value has been described as an example, they may be combined. In this case, the same effect as described above can be obtained.

  In the first and second embodiments, the interlock switch 17 is provided between the emission device 16 and the high-frequency power source 19 in the synchrotron 12 as the interlock means, and the interlock switch 17 is opened. Although the case where the emission of the charged particle beam from the synchrotron 12 is stopped as an example has been described, the present invention is not limited to this. That is, for example, a shutter may be provided in the beam transport system 4, and the shutter may be closed to stop the emission of the charged particle beam to the irradiation device 5. In such a case, the same effect as described above can be obtained.

  In the first and second embodiments described above, the case of spot irradiation control, that is, the case of irradiating a beam with the same range while moving the irradiation position discretely is described as an example. The present invention may be applied to the case of irradiating a beam having the same range while continuously moving the irradiation position (in other words, when irradiating the affected part 2a with the beam while changing the irradiation position). In this case, the same effect as described above can be obtained.

It is the schematic showing the whole structure of the particle beam therapy system in the 1st Embodiment of this invention. It is the schematic showing the structure of the irradiation apparatus in the 1st Embodiment of this invention with an irradiation control apparatus. It is a figure which represents typically the dose distribution of the depth direction of the affected part in a beam. It is a figure which represents typically the dose distribution of the radial direction of a beam. It is a figure showing the example of arrangement | positioning of the spot irradiation position in spot irradiation control. It is a block diagram showing the functional structure regarding the interlock control of the irradiation control apparatus in the 1st Embodiment of this invention. It is a figure for demonstrating the function of the 2nd dose monitor in the 1st Embodiment of this invention. It is a flowchart showing the control processing content of the spot irradiation control in the 1st Embodiment of this invention. It is a flowchart showing the detailed procedure of the interlock control of step 130 in FIG. It is a flowchart showing the control processing content of the spot irradiation control in the 2nd Embodiment of this invention. It is a flowchart showing the detailed procedure of the 1st interlock control of step 240 in FIG. It is a flowchart showing the detailed procedure of the 2nd interlock control of step 280 in FIG.

Explanation of symbols

2a affected part 3 charged particle beam generator 5 irradiation device 6 irradiation control device (integrated irradiation amount calculation means, first storage means, first interlock means)
6A Irradiation control device (integrated dose calculation means, uniformity calculation means, second storage means, second interlock means)
17 Interlock switch (first interlock means, second interlock means)
21A Scanning electromagnet 21B Scanning electromagnet 27 Second dose monitor (detector)

Claims (8)

A charged particle beam generator that accelerates and emits a charged particle beam; and a scanning electromagnet that deflects the charged particle beam emitted from the charged particle beam generator and scans the scanning surface, and passes through the scanning electromagnet. A charged particle beam irradiation system including an irradiation device that irradiates an irradiation target with the charged particle beam.
A detector for detecting an irradiation amount in each of a plurality of partitioned areas partitioned so that the scanning plane is smaller than a beam cross-sectional area;
An integrated dose calculation means for calculating an integrated dose in each of the plurality of partitioned regions when the beam having the same range is irradiated while moving a position on the scanning plane, and based on a detection result of the detector;
First storage means for storing a preset allowable value of integrated dose;
When the integrated dose calculated by the integrated dose calculation means is compared with the allowable value stored in the first storage means, and it is determined that the integrated dose exceeds the allowable value, the charged particle beam is generated. A charged particle beam irradiation system comprising: first interlock means for stopping beam emission from an apparatus to the irradiation apparatus.   2. The charged particle beam irradiation system according to claim 1, wherein the first storage means stores an allowable value obtained by multiplying a target value of the integrated irradiation amount by a different allowable coefficient depending on a range of the beam. Charged particle beam irradiation system.   2. The charged particle beam irradiation system according to claim 1, wherein the first storage unit is assumed to irradiate the same position on the scanning surface with a beam having the same range in a plurality of times. A charged particle beam irradiation system that stores an allowable value obtained by multiplying a target value of an integrated dose by a different allowable coefficient depending on a stage. A charged particle beam generator that accelerates and emits a charged particle beam; and a scanning electromagnet that deflects the charged particle beam emitted from the charged particle beam generator and scans the scanning surface, and passes through the scanning electromagnet. A charged particle beam irradiation system including an irradiation device that irradiates an irradiation target with the charged particle beam.
A detector for detecting an irradiation amount in each of a plurality of partitioned areas partitioned so that the scanning plane is smaller than a beam cross-sectional area;
An integrated dose calculation means for calculating an integrated dose in each of the plurality of partitioned regions when the beam having the same range is irradiated while moving a position on the scanning plane, and based on a detection result of the detector;
Uniformity calculating means for calculating the uniformity of the integrated dose in the same dose area composed of a plurality of divided areas having the same target value of the integrated dose based on the calculation result of the integrated dose calculation means;
A second storage means for storing an allowable value of the uniformity of the preset integrated dose;
The uniformity of the integrated dose calculated by the uniformity calculation means is compared with the allowable value stored in the second storage means, and it is determined that the uniformity of the integrated dose exceeds the allowable value. A charged particle beam irradiation system comprising: a second interlock unit that stops emission of the beam from the charged particle beam generator to the irradiation device.   5. The charged particle beam irradiation system according to claim 4, wherein the second storage means stores an allowable value of uniformity of different integrated irradiation amounts depending on a range of the beam. system.   5. The charged particle beam irradiation system according to claim 4, wherein the second storage unit is assumed to irradiate the same position on the scanning surface with a beam having the same range in a plurality of times, A charged particle beam irradiation system that stores an allowable value of uniformity of different integrated doses depending on a stage. In a charged particle beam irradiation method of irradiating an irradiation target with a charged particle beam by an irradiation device having a scanning electromagnet that deflects the charged particle beam emitted from the charged particle beam generator and scans the scanning surface,
Based on the detection result of the detector that detects the amount of irradiation in each of a plurality of partitioned areas partitioned so that the scanning plane is smaller than the beam cross-sectional area, the beam having the same range is moved on the scanning plane. Calculate the integrated dose in each of the plurality of partitioned areas when irradiated,
The calculated integrated irradiation amount is compared with an allowable value set and stored in advance in the storage means, and when it is determined that the integrated irradiation amount exceeds the allowable value, beam emission from the charged particle beam generator to the irradiation device is performed. A charged particle beam irradiation method characterized by stopping the operation. In a charged particle beam irradiation method of irradiating an irradiation target with a charged particle beam by an irradiation device having a scanning electromagnet that deflects the charged particle beam emitted from the charged particle beam generator and scans the scanning surface,
Based on the detection result of the detector that detects the amount of irradiation in each of a plurality of partitioned areas partitioned so that the scanning plane is smaller than the beam cross-sectional area, the beam having the same range is moved on the scanning plane. Calculate the integrated dose in each of the plurality of partitioned areas when irradiated,
Based on the calculation result, calculate the uniformity of the integrated dose in the same dose area composed of a plurality of divided areas with the same target value of the integrated dose,
When the calculated uniformity of the integrated dose is compared with the allowable value preset and stored in the storage means, and it is determined that the uniformity of the integrated dose exceeds the allowable value, the charged particle beam generator The charged particle beam irradiation method is characterized in that the emission of the beam to the irradiation device is stopped.

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