JP6184544B2 - Treatment planning device and particle beam treatment device - Google Patents

Description

  The present invention relates to a medical device (hereinafter referred to as a “particle beam therapy device”) that performs treatment by irradiating an affected area such as cancer with a charged particle beam (hereinafter referred to as “particle beam”) represented by a heavy particle beam such as carbon or a proton beam. )

  In medical devices that use X-rays and other radiations that were developed prior to particle beam therapy devices, the affected area can be uniformly irradiated at high doses by irradiating radiation with adjusted intensity from multiple directions. Treatments have been proposed to reduce exposure to surrounding tissue. Here, irradiating the affected area from multiple directions is called multi-port irradiation.

  Several methods have been proposed for multi-port irradiation. IMRT (Intensity-Modulated Radiotherapy) (Non-Patent Document 1, Non-Patent Document 2) and ELEKTA are used to perform step and shoot with a focus on Siemens. Examples include IMAT (Intensity-Modulated Arc Therapy) (Non-patent Document 3).

  Patented radiation irradiation device that has multiple compensators that change the spatial pattern of the X-ray intensity distribution for each irradiation direction to give a high absorbed dose only to the affected area, and that automatically changes the compensator for each irradiation direction and performs multi-port irradiation It is proposed in Document 1.

Japanese Patent Laying-Open No. 2005-37214 (FIGS. 17 to 21)

Chui CS, Spirou SV.Inverse planning algorithms for external beam radiation therapy.Med Dosim 2001; 26 (2): 189-197 Keller-Reichenbecher MA, Bortfeld T, Levegrun S, et al. Intensity modulation with the "step and shoot" technique using a commercial MLC: a planning study.Multileaf collimator.Int J Radiat Oncol Biol Phys 1999; 45 (5): 1315 -1324. Yu CX. Intensity-modulated arc therapy with dynamic multileaf collimation: an alternative to tomotherapy.Phys Med Biol. 1995; 40 (9): 1435-1449. Urgent statement on intensity modulated radiation therapy. JASTRO NEWSLETTER 2002; 63 (3): 4-7.

  In radiotherapy equipment such as X-rays, IMRT has been used for many clinical applications in the head and neck region, prostate, etc., and has achieved excellent results, but problems such as over-irradiation have also been pointed out. According to Non-Patent Document 4, depending on the treatment plan contents, IMRT may cause an adverse event in normal tissue due to over-irradiation, regardless of whether or not it increases with a single line amount or total dose consciously, On the contrary, it warns that it becomes conservative and there is a risk of insufficient therapeutic effect due to underdose irradiation.

  One of the causes of this over-irradiation is thought to be due to insufficient degree of freedom of irradiation. The final irradiation field of IMRT by the radiotherapy apparatus such as X-ray shown in Non-Patent Document 1 to Non-Patent Document 4 is (1) irradiation energy, (2) irradiation angle, (3) multi-leaf collimator (hereinafter “ This is realized by superimposing a plurality of irradiations with the irradiation field limitation in the horizontal direction by (MLC)) and the like and (4) irradiation dose (weight) as parameters. There is no irradiation field limiter in the depth direction here.

  A bolus used in a particle beam therapy system is an example of a depth field limiter. The change shape of the affected part in the depth direction is called a distal shape. The bolus is an energy modulator that is processed according to this distal shape, and is made by processing polyethylene or wax for each patient. An irradiation apparatus equipped with a bolus is shown in FIG. 21 of Patent Document 1, for example, and can match the shape of the irradiation field to the distal shape of the affected area.

  However, one bolus cannot be directly applied to multi-port irradiation in the particle beam therapy system. First, in the case of IMRT, a bolus must be prepared for each of a plurality of irradiation directions. Although the radiation irradiation apparatus of Patent Document 1 can automatically move a compensator corresponding to a bolus, there is a problem that labor and cost of bolus processing are high. In addition, in the case of IMAT, it is more difficult, and the shape of the bolus must be changed dynamically according to the irradiation angle that changes every moment. Currently, this dynamic shape change cannot be realized with a bolus.

  Therefore, if the technique of IMRT in a radiotherapy apparatus such as X-ray is applied to a particle beam therapy apparatus having a conventional wobbler system as it is, there is a problem that a plurality of boluses must be used. Since the irradiation field in the depth direction is not limited without using a bolus, that is, the degree of irradiation freedom cannot be increased, the over-irradiation problem cannot be solved without using a bolus.

  The present invention aims to solve these problems. That is, the object is to solve the IMRT over-irradiation problem in the particle beam therapy system. More specifically, the IMRT over-irradiation problem in the particle beam therapy system is solved by increasing the degree of freedom of irradiation in the depth direction without using a bolus.

An X-direction scanning magnet that scans the charged particle beam accelerated by the accelerator in the X-direction and Y-direction perpendicular to the irradiation direction, a scanning irradiation system that scans in the X-direction and Y-direction by the Y-direction scanning magnet, and a charged particle beam Is a treatment planning device that creates a treatment plan for a particle beam therapy system that includes a columnar irradiation field generation device that expands the Bragg peak and generates a columnar irradiation field. The columnar irradiation field is the width of the SOBP in which the height of the columnar irradiation field is the width in the irradiation direction of the charged particle beam, and the length of the cross section perpendicular to the axis in the height direction of the columnar irradiation field is The beam size is the width of the charged particle beam in the X and Y directions, and is the size of the charged particle beam that has not been forcibly expanded after being emitted from the accelerator, and the height of the columnar irradiation field is The irradiation field is longer than the beam size, and the beam size is a single size selected in one treatment irradiation. Depending on the distal shape of the irradiation target irradiated with the charged particle beam, one SOBP The outer columnar irradiation field, which is a columnar irradiation field having a width, is arranged, and the inner columnar irradiation field, which is a columnar irradiation field having a different SOBP width from the outer columnar irradiation field, is arranged on the inner side of the irradiation target. The irradiation dose to the irradiation target is set to a predetermined value with the irradiation field arrangement part arranged so as to overlap with the inner edge and the state where the outer columnar irradiation field and the inner columnar irradiation field are spread by the irradiation field arrangement part as an initial state. And an optimization calculation unit that adjusts the arrangement of the outer columnar irradiation field and the inner columnar irradiation field to fall within the range.

The treatment planning apparatus according to the present invention lays out a columnar irradiation field in which the Bragg peak of the charged particle beam is enlarged according to the distal shape of the irradiation target, so that the irradiation dose to the irradiation target falls within a predetermined range. Since the arrangement of the irradiation field is adjusted, the IMRT over-irradiation problem in the particle beam therapy system can be solved by increasing the degree of freedom of irradiation in the depth direction without using a bolus.

It is a block diagram which shows the particle beam irradiation apparatus by Embodiment 1 of this invention. It is a block diagram which shows the energy change apparatus of FIG. It is a block diagram which shows the depth direction irradiation field expansion apparatus of FIG. It is a flowchart which shows the preparation method of the treatment plan used in the particle beam irradiation apparatus of this invention. It is a figure explaining step ST1 of FIG. It is a schematic diagram which calculates | requires the initial state in the optimal calculation of the treatment plan of this invention. It is a block diagram which shows the energy change apparatus by Embodiment 2 of this invention. It is a block diagram which shows the depth direction irradiation field expansion apparatus by Embodiment 3 of this invention. It is a block diagram which shows the columnar irradiation field production | generation apparatus by Embodiment 4 of this invention. It is an external view which shows RMW by Embodiment 5 of this invention. It is a block diagram which shows the depth direction irradiation field expansion apparatus by Embodiment 5 of this invention. It is a block diagram which shows the depth direction irradiation field expansion apparatus by Embodiment 6 of this invention. It is a block diagram which shows the columnar irradiation field production | generation apparatus by Embodiment 7 of this invention. It is a block diagram which shows the particle beam irradiation apparatus by Embodiment 8 of this invention. It is a block diagram which shows the particle beam therapy apparatus by Embodiment 9 of this invention.

Embodiment 1 FIG.
Consider IMRT with columnar scanning irradiation, which is a feature of the present invention. The general idea of spot scanning is to irradiate an affected area with a spot in a three-dimensional manner as if it were pointed. Spot scanning is an irradiation method with such a high degree of freedom, but on the other hand, it takes a long time to irradiate the entire affected area. Since IMRT is multi-port irradiation, it takes more time. Therefore, a Bragg peak BP is expanded in the depth direction from the spot to generate a columnar irradiation field.

  FIG. 1 is a block diagram showing a particle beam irradiation apparatus according to Embodiment 1 of the present invention. The particle beam irradiation device 58 expands the Bragg peak BP in the depth direction, generates a columnar irradiation field 4, and charges in the X and Y directions that are perpendicular to the charged particle beam 1. X-direction scanning electromagnet 10 and Y-direction scanning electromagnet 11 that scan the particle beam 1, position monitors 12 a and 12 b, dose monitor 13, scanning electromagnet power supply 32, and irradiation control that controls the irradiation system of the particle beam irradiation device 58. Device 33. The X-direction scanning electromagnet 10, the Y-direction scanning electromagnet 11, and the scanning electromagnet power supply 32 are a scanning irradiation system 34 that scans the charged particle beam 1. The traveling direction of the charged particle beam 1 is the Z direction. The columnar irradiation field generating device 4 reduces the energy of the charged particle beam from the near side toward the traveling direction of the charged particle beam and changes it to a desired energy, and the depth direction of the Bragg peak BP in the affected area 40 to be irradiated ( An energy changing device 2 that adjusts the position (range) in the Z direction) and a depth direction irradiation field expanding device 3 that changes the energy width of the charged particle beam 1 and expands the Bragg peak BP in the depth direction. Have. The Bragg peak BP in which the width of the affected part 40 in the depth direction, that is, the width in the irradiation direction is expanded is called an expanded Bragg peak SOBP (Spread-Out Bragg Peak). Here, the width in the irradiation direction of the enlarged Bragg peak SOBP is referred to as the SOBP width.

  The X direction scanning electromagnet 10 is a scanning electromagnet that scans the charged particle beam 1 in the X direction, and the Y direction scanning electromagnet 11 is a scanning electromagnet that scans the charged particle beam 1 in the Y direction. The position monitors 12a and 12b detect passing positions through which the charged particle beam 1 scanned by the X-direction scanning electromagnet 10 and the Y-direction scanning electromagnet 11 passes. The dose monitor 13 detects the dose of the charged particle beam 1. The irradiation control device 33 controls the columnar irradiation field and its irradiation position in the affected part 40 based on the treatment plan data created by the treatment planning device (not shown), and when the dose measured by the dose monitor 13 reaches the target dose. Stop the charged particle beam. The scanning electromagnet power supply 32 changes the set currents of the X-direction scanning electromagnet 10 and the Y-direction scanning electromagnet 11 based on control inputs (commands) to the X-direction scanning electromagnet 10 and the Y-direction scanning electromagnet 11 output from the irradiation control device 33. Let

  FIG. 2 is a block diagram showing the energy changing device. FIG. 3 is a block diagram showing a depth direction irradiation field enlarging apparatus. The energy changing device 2 includes a range shifter 9 whose thickness changes stepwise in the width direction (X direction), a deflection electromagnet 5 constituting an upstream deflection electromagnet pair that moves a position where the charged particle beam 1 passes through the range shifter 9, 6. First deflection electromagnet power source 20 for exciting the upstream deflection electromagnet pair, deflection electromagnets 7, 8 constituting the downstream deflection electromagnet pair for returning the charged particle beam 1 having passed through the range shifter 9 to the original trajectory, downstream Based on the energy command value input from the second deflection magnet power source 21 and the irradiation control device 33 for exciting the deflection magnet pair, the moving amount of the charged particle beam trajectory by the upstream deflection magnet pair is calculated, and the excitation current value is calculated. A change control device 22 for transmitting to the first bending electromagnet power source 20 is provided. The change control device 22 also controls the second bending electromagnet power source 21.

  The charged particle beam 1 is incident on the upstream deflection electromagnet pairs 5 and 6 on the beam axis 14 (Z axis). The trajectory of the charged particle beam 1 is moved in the horizontal direction (X direction) in FIG. The deflection electromagnet 5 is a deflection electromagnet for orbital deflection, and the deflection electromagnet 6 is a deflection electromagnet for orbital parallelism. The trajectory changing deflection electromagnet 5 deflects the trajectory of the incident charged particle beam 1 so as to be inclined by a predetermined angle θ with respect to the Z axis. The trajectory parallel deflecting electromagnet 6 deflects the trajectory tilted with respect to the Z axis by the trajectory changing deflecting electromagnet 5 into a trajectory parallel to the Z axis. On the downstream side of the range shifter 9, the charged particle beam 1 is returned onto the beam axis 14 (Z axis) by the deflecting electromagnet 7 for orbital deflection and the deflecting electromagnet 8 for orbital parallelism. The deflecting electromagnet 7 for changing the trajectory deflects the trajectory of the charged particle beam 1 so as to be inclined by (360 degrees−predetermined angle θ) with respect to the Z axis. The orbit parallel deflecting electromagnet 8 deflects the orbit inclined with respect to the Z axis by the orbit changing deflecting electromagnet 7 to the orbit on the Z axis.

  The operation of the energy changing device 2 will be described. The charged particle beam 1 introduced into the energy changing device 2 travels on a trajectory parallel to the Z axis that is separated from the Z axis by a predetermined distance in the X direction by the upstream deflection magnet pairs 5 and 6. Then, when the charged particle beam 1 passes through the range shifter 9 having a predetermined thickness, the energy is reduced by an amount proportional to the thickness to obtain a desired energy. The charged particle beam 1 thus changed to the desired energy is returned to the extension line of the original trajectory when it is incident on the energy changing device 2 by the downstream deflection electromagnet pairs 7 and 8. The energy changing device 2 has an advantage that the driving sound for driving the range shifter is not generated when changing to energy and changing the range. The trajectory of the charged particle beam 1 deflected by the downstream deflection electromagnet pairs 7 and 8 is not limited to returning on the beam axis 14, but when returning to the beam axis 14 parallel to the beam axis 14, the beam axis Even if it is not parallel to 14, it may return to the beam axis 14.

  FIG. 3 is a block diagram showing a depth direction irradiation field enlarging apparatus. The depth direction irradiation field expanding device 3 is composed of approximately triangular prisms having different heights in the width direction (X direction), that is, a ridge filter 19 and a ridge filter 19 configured to have a plurality of peaks having different thickness distributions. The deflection electromagnets 15 and 16 constituting the upstream deflection electromagnet pair moving the position where the charged particle beam 1 passes, the first deflection electromagnet power source 23 for exciting the upstream deflection electromagnet pair, and the charged particles that have passed through the ridge filter 19 The deflection electromagnets 17 and 18 constituting the downstream deflection electromagnet pair for returning the beam 1 to the original trajectory, the second deflection electromagnet power supply 24 for exciting the downstream deflection electromagnet pair, and the SOBP command value input from the irradiation controller 33 And a change control device 25 for calculating the moving amount of the charged particle beam trajectory by the upstream deflection electromagnet pair and transmitting the excitation current value to the first deflection electromagnet power source 23. That. The change control device 25 also controls the second bending electromagnet power supply 24.

  The charged particle beam 1 is incident on the upstream deflection electromagnet pairs 15 and 16 on the beam axis 14 (Z axis). The trajectory of the charged particle beam 1 is moved in the horizontal direction (X direction) in FIG. The deflection electromagnet 15 is a deflection electromagnet for changing the orbit, and the deflection electromagnet 16 is a deflection electromagnet for orbital parallelism. The trajectory changing deflection electromagnet 15 deflects the trajectory of the incident charged particle beam 1 so as to be inclined by a predetermined angle θ with respect to the Z axis. The orbit parallel deflecting electromagnet 16 deflects the orbit inclined with respect to the Z axis by the orbit changing deflecting electromagnet 15 into an orbit parallel to the Z axis. On the downstream side of the ridge filter 19, the charged particle beam 1 is returned onto the beam axis 14 (Z axis) by the deflecting electromagnet 17 for orbital deflection and the deflecting electromagnet 18 for orbital parallelism. The deflecting electromagnet 17 for changing the trajectory deflects the trajectory of the charged particle beam 1 so as to be inclined by (360 degrees−predetermined angle θ) with respect to the Z axis. The orbit parallel deflecting electromagnet 18 deflects the orbit inclined with respect to the Z axis by the orbit changing deflecting electromagnet 17 to the orbit on the Z axis.

  Operation | movement of the depth direction irradiation field expansion apparatus 3 is demonstrated. The charged particle beam 1 introduced into the depth direction irradiation field expanding device 3 travels on a trajectory parallel to the Z axis, which is separated from the Z axis by a predetermined distance in the X direction by the upstream deflection electromagnet pairs 15 and 16. Then, when the charged particle beam 1 passes through the portion of the ridge filter 19 having a predetermined thickness distribution, the energy is reduced by an amount proportional to the thickness, and as a result, various kinds of energy whose intensity changes are mixed. Become a particle beam. The width of the SOBP can be changed according to the height of the ridge of the ridge filter 19 through which the charged particle beam 1 passes. The charged particle beam 1 thus changed to the desired SOBP width is returned to the extension of the original trajectory when it is incident on the depth direction irradiation field expanding device 3 by the downstream deflection magnet pairs 17 and 18. It is. The depth direction irradiation field expanding device 3 has an advantage that the driving sound for driving the ridge filter is not generated when the width of the SOBP is changed. It should be noted that the trajectory of the charged particle beam 1 deflected by the downstream deflection electromagnet pairs 17 and 18 is not limited to returning on the beam axis 14, but when returning to the beam axis 14 parallel to the beam axis 14, the beam axis Even if it is not parallel to 14, it may return to the beam axis 14.

  By mounting the particle beam irradiation device 58 on the rotating gantry, the irradiation system of the particle beam irradiation device 58 can freely rotate around the patient table, and the affected part 40 can be irradiated from multiple directions. The rotating gantry rotates the irradiation system of the particle beam irradiation device 58 and rotates the irradiation direction. That is, this allows multi-gate irradiation. Further, by using the ridge filter 19 in the particle beam irradiation device 58 so as to expand the irradiation field in the Z direction larger than the XY direction, a columnar dose distribution with respect to the affected area 40 (see FIG. 5). A beam can be irradiated.

  Next, a method for performing IMRT by columnar scanning irradiation will be described. FIG. 4 is a flowchart showing a method for creating a treatment plan used in the particle beam irradiation apparatus of the present invention, FIG. 5 is a diagram for explaining step ST1 in FIG. 4, and FIG. 6 is an initial state in the optimum calculation of the treatment plan. FIG. 5 and 6 show an example in which irradiation is performed at four gates (at intervals of 90 degrees). The treatment planning apparatus for creating a treatment plan arranges a columnar irradiation field according to the distal shape of the affected part (irradiation target) 40 to which the charged particle beam 1 is irradiated, and has a columnar shape inside the affected part (irradiation target) 40. The irradiation field placement unit that lays out the irradiation field and the state where the columnar irradiation field is laid down by the irradiation field placement unit are set as an initial state so that the irradiation dose to the affected part (irradiation target) 40 falls within a predetermined range. An optimization calculation unit for adjusting the arrangement of the columnar irradiation field is provided. The treatment plan includes the operating conditions of the particle beam irradiation device 58 and the rotating gantry, and the particle beam irradiation device 58 and the rotating gantry operate integrally based on the treatment plan.

  First, as shown in FIG. 5, columnar irradiation fields 44a, 44b, 44c, and 44d, which are columnar irradiation fields, are spread in accordance with the distal shape of the affected area 40 (step ST1). This is performed for all gates (irradiation direction). At this time, the columnar irradiation fields may overlap. The overlapping part will be explained later. FIG. 5A shows an example in which the columnar irradiation field 44a is spread according to the distal shape of the affected part 40 in the irradiation from the irradiation direction 43a, and FIG. 5B shows the columnar irradiation when the irradiation direction is the irradiation direction 43b. 5C shows a columnar irradiation field 44c when the irradiation direction is the irradiation direction 43c, and FIG. 5D shows a columnar irradiation field 44d when the irradiation direction is the irradiation direction 43d. FIG. 6A shows an example of the arrangement of the irradiation field when completed in all gates (irradiation direction).

  When all the gates (irradiation directions) are completed, it is determined whether there is a remaining irradiation target region (step ST2). If there is no remaining irradiation target area, the process proceeds to step ST5. If there is a remaining irradiation target area, a second round of laying operation is performed on the remaining irradiation target area so as to match the distal shape of the remaining irradiation target (step ST3). As shown in FIG. 6B, when the irradiation direction is the irradiation direction 43c, the columnar irradiation field 45c is spread. At this time, the columnar irradiation field in the second round may be changed in width between the columnar irradiation field in the first round and the SOBP. An example of the arrangement of the irradiation field when completed at all gates (irradiation direction) is as shown in FIG. In FIG. 6C, the columnar irradiation field 45a is the case where the irradiation direction is the irradiation direction 43a, the columnar irradiation field 45b is the case where the irradiation direction is the irradiation direction 43b, and the columnar irradiation field 45d is the irradiation direction 43d. This is the case.

  When all the gates (irradiation direction) in the second round are completed, it is determined whether there is a remaining irradiation target region (step ST4). If there is a remaining region to be irradiated, the process proceeds to step ST3 and is repeated so that the columnar irradiation field covers the entire affected area. If there is no remaining irradiation target area, the process proceeds to step ST5.

  In step ST5, optimization calculation is performed using an irradiation plan in which columnar irradiation fields are spread as initial values. When the optimization calculation is completed, evaluation is performed using an evaluation function (step ST6). It is determined whether the value of the evaluation function is clinically acceptable. If it is determined that the evaluation function is not acceptable, the process returns to step ST5 and optimization calculation is performed. If the value of the evaluation function is within a clinically acceptable range, the process ends.

  In the optimization of the treatment plan shown in steps ST5 and ST6, in order to prevent overdose (excess dose), the arrangement of columnar irradiation fields is adjusted so that the irradiation dose to the affected area 40 falls within a predetermined range. Since the portion where the columnar irradiation field overlaps becomes overdose (dose excess), the optimization work eliminates or reduces the portion where the columnar irradiation field overlaps. Change the placement of.

  The operations in steps ST1 to ST4 are first performed in the irradiation field arrangement unit of the treatment planning apparatus. Next, the treatment planning apparatus will be described. Regarding the treatment planning device, the operation manual of the radiation treatment planning device for medical safety (Kozo Kumagai, Japan Radiological Engineers Association Publishing) is detailed. Although the treatment planning apparatus has a wide range of roles, it can be said that it is a treatment simulator in simple terms. One of the roles of the treatment planning apparatus is optimization calculation. The optimization of the treatment plan shown in steps ST5 and ST6 is performed by the optimization calculation unit of the treatment plan apparatus. The optimization calculation is used to search for the optimum beam intensity in inverse treatment planning (inverse planning) in IMRT.

  According to the operation manual, the following has been tried for the optimization calculation so far. The filter backprojection method used in the initial IMRT optimization calculation, pseudo-annealing classified into probabilistic methods, genetic algorithm, random search technology, and determinism currently implemented in many treatment planning devices It is a gradient method classified as a general method.

  The gradient method is fast in calculation, but has the property that it cannot escape when captured by a local minimum (minimum). However, the gradient method is currently employed in many treatment planning devices that implement clinical IMRT treatment planning.

  In order to prevent the gradient method from being caught by another local minimum value different from the optimum to be obtained, it is also effective to use it in combination with other genetic algorithms and random search techniques. In addition, it has been empirically known that the initial value of optimization calculation (the value initially given as a solution candidate) should be close to the optimum solution to be obtained.

  Therefore, in the present invention, the irradiation plan created in steps ST1 to ST4 is used as an initial value for optimization calculation. Compared to the conventional IMRT, the irradiation plan in steps ST1 to ST4 is sufficiently close to the optimal irradiation because the degree of freedom of irradiation in the depth direction is high so as to match the distal shape of the affected area.

ここでＤ_ｍｉｎ、Ｄ_ｍａｘは指定した線量制限である。ｕはＤ_ｍｉｎに対する重み係数であり、ｗはＤ_ｍａｘに対する重み係数である。ｂ（数式（１）では矢印付きで示したが、矢印なしで示す。以後、数式（１）関連の説明において同じ。）はビームレットの強度の関数であり、ｄ_ｉ（ｂ）はビームレットの強度の関数ｂとしたボクセルｉの線量である。［ｘ］_＋はｘ＞０ではｘ、それ以外では０となる。Ｎはボクセルの最大数である。 The optimization calculation always calculates a solution that minimizes a certain evaluation function. In the case of the treatment planning apparatus, as shown in the operation manual, the evaluation function that is a reference for physical optimization is shown as follows.

Here, D _min and D _max are specified dose limits. u is a weighting factor for _Dmin , and w is a weighting factor for _Dmax . b (shown with an arrow in Formula (1), but without an arrow. Hereinafter, the same applies to the description related to Formula (1)) is a function of the intensity of the beamlet, and d _i (b) is a beamlet. Is the dose of voxel i as a function of intensity b. [X] ₊ is x when x> 0, and 0 otherwise. N is the maximum number of voxels.

  As described above, since the optimization calculation is performed in the treatment planning apparatus, for example, even if the columnar irradiation fields overlap and become overdose (excess dose) in the initial value, adjustment is made in the obtained treatment plan.

  With the configuration as described above, according to the treatment planning apparatus of the first embodiment, it is possible to increase the degree of freedom in irradiation in the depth direction without using a bolus, and the IMRT over-irradiation problem in the particle beam therapy apparatus Can be solved.

  The effect of irradiating a beam with a columnar dose distribution will be described. In the first place, in the conventional particle beam therapy system premised on irradiation from one direction, the dose distribution in the irradiation system is formed by the following method. The wobbler method will be described as an example. In the XY direction, the irradiation field is uniformly enlarged by a wobbler electromagnet and a scatterer, and limited by MLC based on the XY plane cross-sectional shape (or the shape projected on the XY plane, etc.) of the affected area. . In the Z direction, the irradiation field is uniformly enlarged by a ridge filter, and the bolus is limited so as to match the distal shape (deepest layer shape) of the affected area.

  As mentioned above, multiple portals must be used for multi-port irradiation in a particle beam therapy system, which requires labor and cost for bolus processing, and the shape of the bolus cannot be changed dynamically. There wasn't. If the irradiation field can be limited to match the distal shape (deepest layer shape) of the affected area like a bolus without using a bolus in multi-port irradiation in a particle beam therapy system, the effort and cost of bolus processing This problem can be solved and application to IMAT becomes possible, and the IMRT over-irradiation problem, that is, unnecessary irradiation to normal tissues can be significantly reduced. Thus, the inventors have come up with an invention for irradiating a beam with a columnar dose distribution. One of the greatest effects of irradiating a beam with a columnar dose distribution in the present invention is that the irradiation field can be limited to match the distal shape (deepest layer shape) of the affected area 40 without using a bolus. In other words, unnecessary irradiation to normal tissues can be significantly reduced.

  Another greatest effect of irradiating a beam with a columnar dose distribution in the present invention is that an irradiation field can be formed without intensity modulation used in a radiotherapy apparatus such as an X-ray. Here, the principle of intensity modulation is simply to irradiate an irradiation field with a weak dose distribution from multiple directions, and as a radiation field where a place where more doses finally overlap with each other by applying superposition will exert a therapeutic effect It is to obtain a dose distribution.

  In the present invention, the irradiation field can be formed by combining columnar doses as shown in FIG. Although supplemented here, in the present invention, irradiation may be performed with overlapping irradiation fields. Underdose and overdose are not allowed for each part of the affected area, but there are a range of clinically acceptable doses. An irradiation plan is made by the treatment planning apparatus so that the final dose distribution is acceptable for each part of the affected area. Unlike conventional X-ray and other radiotherapy devices, it is not necessary to modulate the intensity of the final irradiation field so that it matches the distal shape of the affected area. That is, the problem that the time required for the conventional treatment plan is long can be solved. Further, irradiating a beam with a columnar dose distribution has an advantage that the irradiation time is shorter than that of irradiating in a spot shape.

  The particle beam therapy system using the therapy planning apparatus according to the first embodiment has several merits that allow multi-port irradiation, but there are mainly the following two points. One is that when the same affected area is irradiated, the multi-portion irradiation has a larger body surface area through which the particle beam passes, so that damage to the body surface, which is a normal tissue, can be reduced. The other is that it is possible to avoid irradiating a dangerous part (spinal cord, eyeball, etc.) that should not be irradiated.

  As described above, the particle beam irradiation apparatus according to the first embodiment includes the scanning irradiation system 34 that scans the charged particle beam 1 accelerated by the accelerator, and is mounted on the rotating gantry that rotates the irradiation direction of the charged particle beam 1. Since the particle beam irradiation apparatus 58 includes the columnar irradiation field generation apparatus 4 that expands the Bragg peak of the charged particle beam 1 and generates a columnar irradiation field, the charged particle beam irradiation apparatus 58 is provided. A columnar irradiation field with an enlarged Bragg peak can be irradiated to a depth corresponding to the distal shape of the irradiation target to generate this columnar irradiation field, and the degree of freedom of irradiation in the depth direction can be increased without using a bolus. And the IMRT over-irradiation problem in the particle beam therapy system can be solved.

Embodiment 2. FIG.
FIG. 7 is a block diagram showing an energy changing device according to the second embodiment of the present invention. The energy changing device 2a according to the first embodiment uses a plurality of absorbers 26a, 26b, 26c, and 26d to reduce the energy of the charged particle beam 1 to change it to a desired energy, and the affected part 40 that is an irradiation target. Is different in that the position (range) of the Bragg peak BP in the depth direction (Z direction) is adjusted.

  The energy changing device 2b includes a plurality of absorbers 26a, 26b, 26c, and 26d that are driven by the driving devices 27a, 27b, 27c, and 27d. The absorbers 26a, 26b, 26c, and 26d are absorbers having different thicknesses. The total thickness of the absorber can be changed by the combination of the absorbers 26a, 26b, 26c, and 26d. The change control device 22 controls the drive devices 27a, 27b, 27c, and 27d so that the charged particle beam 1 passes through or does not pass through the absorbers 26a, 26b, 26c, and 26d corresponding to the drive devices. To. The charged particle beam 1 is reduced in energy by a proportion proportional to the total thickness of the absorber passing therethrough to become a desired energy.

  The particle beam irradiation apparatus (see FIG. 1) having the energy changing device 2b according to the second embodiment can expand the Bragg peak BP in the depth direction and generate a columnar irradiation field, as in the first embodiment. it can. Since the energy changing device 2b according to the second embodiment does not need to deflect the charged particle beam 1, the deflecting electromagnets 5 to 8 are eliminated and the charged particle beam 1 is irradiated as compared with the energy changing device 2a according to the first embodiment. The length L1 of the device in the direction (Z direction) can be shortened. Since the length L1 of the device can be shortened, the energy changing device can be made compact. 2 is the length from the upstream end of the deflection electromagnet 5 to the downstream end of the deflection electromagnet 8. In FIG.

  The particle beam irradiation apparatus (see FIG. 1) having the energy changing device 2b according to the second embodiment can execute multi-port irradiation based on a treatment plan corresponding to the treatment plan created by the treatment planning apparatus shown in the first embodiment. Therefore, as in the first embodiment, the degree of freedom in irradiation in the depth direction can be increased without using a bolus, and the IMRT over-irradiation problem in the particle beam therapy system can be solved.

Embodiment 3 FIG.
FIG. 8 is a block diagram showing a depth direction irradiation field enlarging apparatus according to Embodiment 3 of the present invention. The depth direction irradiation field expanding device 3a of the first embodiment uses a plurality of ridge filters 28a, 28b, 28c, and 28d to change the energy of a charged particle beam into a state in which various types of energy are mixed, that is, a charged particle beam. The difference is that the width of energy 1 is changed and the Bragg peak BP is expanded in the depth direction.

  The depth direction irradiation field expansion device 3b includes a plurality of ridge filters 28a, 28b, 28c, and 28d driven by driving devices 29a, 29b, 29c, and 29d. The ridge filters 28a, 28b, 28c, and 28d are ridge filters having different thicknesses. The total thickness of the ridge filter can be changed by combining each of the ridge filters 28a, 28b, 28c, and 28d. The change control device 25 controls the drive devices 29a, 29b, 29c, and 29d so that the charged particle beam 1 passes through or does not pass through the ridge filters 28a, 28b, 28c, and 28d corresponding to the drive devices. To. The width of the energy of the charged particle beam 1 is increased by an amount proportional to the total thickness of the ridge filter that passes, and the desired SOBP width is obtained.

  The particle beam irradiation apparatus (see FIG. 1) having the depth direction irradiation field enlargement apparatus 3b of the third embodiment expands the Bragg peak BP in the depth direction in the same manner as in the first embodiment, thereby forming a columnar irradiation field. Can be generated. Since the depth direction irradiation field expanding device 3b according to the third embodiment does not need to deflect the charged particle beam 1, the deflecting electromagnets 15 to 18 are provided as compared with the depth direction irradiation field expanding device 3a according to the first embodiment. The length L2 of the apparatus in the irradiation direction (Z direction) of the charged particle beam 1 can be shortened. Since the length L2 of the device can be shortened, the depth direction irradiation field expanding device can be made compact. The length L2 of the device in FIG. 3 is the length from the upstream end of the deflection electromagnet 15 to the downstream end of the deflection electromagnet 18.

  The particle beam irradiation apparatus (see FIG. 1) having the depth direction irradiation field expanding apparatus 3b of the third embodiment is based on a treatment plan corresponding to the treatment plan created by the treatment planning apparatus shown in the first embodiment. Since irradiation can be executed, the degree of freedom in irradiation in the depth direction can be increased without using a bolus as in the first embodiment, and the IMRT over-irradiation problem in the particle beam therapy system can be solved.

Embodiment 4 FIG.
FIG. 9 is a block diagram showing a columnar irradiation field generating apparatus according to Embodiment 4 of the present invention. The columnar irradiation field generating device 4a of the first embodiment is different in that the energy changing device 2a and the depth direction irradiation field expanding device 3a are integrated.

  The columnar irradiation field generation device 4b includes two range shifters 9a and 9b, two ridge filters 19a and 19b, and upstream deflection that moves the position where the charged particle beam 1 passes through the range shifters 9a and 9b and the ridge filters 19a and 19b. The charged particle beam 1 that has passed through the deflection electromagnets 5 and 6 constituting the electromagnet pair, the first deflection electromagnet power source 20 that excites the upstream deflection electromagnet pair, the range shifters 9a and 9b, and the ridge filters 19a and 19b is put on the original trajectory. Based on the energy command value input from the deflection electromagnets 7 and 8 constituting the returning downstream deflection electromagnet pair, the second deflection electromagnet power source 21 for exciting the downstream deflection electromagnet pair, and the irradiation control device 33, the upstream deflection electromagnet pair. The change control device that calculates the amount of movement of the charged particle beam trajectory by means of and transmits the excitation current value to the first deflection electromagnet power source 20 Equipped with a 2. The change control device 22 also controls the second bending electromagnet power source 21. Since the operation of each device is the same as in the first embodiment, it will not be repeated.

  The range shifters 9a and 9b are of the same shape and material, and the ridge filters 19a and 19b are examples composed of roughly triangular prisms having different heights. Since the height of the approximate triangular prism of the ridge filter 19b is higher than the height of the approximate triangular prism of the ridge filter 19a, the width of the SOBP of the charged particle beam 1 is greater when passing through the ridge filter 19a than when passing through the ridge filter 19b. Can be wider.

  Since the columnar irradiation field generation device 4b according to the fourth embodiment changes the charged particle beam 1 to the desired energy with the widths of the two types of SOBP, the two types of the shot irradiation field can be set to the desired range. . For each of the range shifters 9a and 9b and the ridge filters 19a and 19b, there is no upstream deflection electromagnet pair and downstream deflection electromagnet pair, and only one set of upstream deflection electromagnet pair and downstream deflection electromagnet pair is provided. Therefore, the length of the apparatus in the irradiation direction (Z direction) of the charged particle beam 1 can be shortened as compared with the columnar irradiation field generation apparatus 4a of the first embodiment. Since the upstream deflecting electromagnet pair and the downstream deflecting electromagnet pair are used to change the energy to the desired energy with two types of SOBP width, the driving sound for driving the range shifter and the ridge filter is generated when the SOBP width and range are changed. There is a merit that does not occur. In order to make the widths of many kinds of SOBP more than two kinds uniform, the range shifter 9 and the ridge filter 19 corresponding to the number of kinds may be arranged.

  The particle beam irradiation apparatus (see FIG. 1) having the columnar irradiation field generation apparatus 4b according to the fourth embodiment performs multiple portal irradiation based on the treatment plan corresponding to the treatment plan created by the treatment planning apparatus shown in the first embodiment. Since it can be executed, the degree of freedom in irradiation in the depth direction can be increased without using a bolus as in the first embodiment, and the IMRT over-irradiation problem in the particle beam therapy system can be solved.

Embodiment 5. FIG.
In the first to fourth embodiments, it has been described that the irradiation field is expanded in the Z direction, that is, SOBP is realized by the ridge filters 19 and 28. In the fifth embodiment, a description will be given of an embodiment in which a range modulation wheel RMW (Range Modulation Wheel) is used in order to expand the irradiation field larger in the Z direction than in the XY direction.

  The RMW is an apparatus used in an irradiation system, that is, an apparatus used for a particle beam irradiation apparatus, and expands an irradiation field in the beam traveling direction to generate SOBP. The RMW may be used in a broad beam irradiation method such as a double scatterer method or a wobbler method in which a beam irradiation field is temporarily expanded and the irradiation field is limited using a collimator or a bolus. An example in which RMW is used in the double scatterer method is shown in Japanese Patent Application Laid-Open No. 2007-222433. The RMW according to the fifth embodiment of the present invention will be described with reference to FIGS.

  FIG. 10 is an external view showing an RMW according to a fifth embodiment of the present invention, and FIG. 11 is a block diagram showing a depth direction irradiation field expanding apparatus according to the fifth embodiment of the present invention. The RMW 35 has a configuration in which a plurality of wedge-shaped energy absorbers (blades) whose axial thickness gradually increases or decreases in the circumferential direction are arranged. In the example of FIG. 10, it has three blade | wings 37a, 37b, 37c. Each of the blades 37a, 37b, and 37c has six bases 36a, 36b, 36c, 36d, 36e, and 36f, and the axial thickness gradually increases in the clockwise circumferential direction from the base 36a toward the base 36f. It has a decreasing shape. The RMW 35 can be expressed using the table 36 as follows. The RMW 35 includes an energy absorber 37 in which a plurality of stages 36a to 36f having axially different thicknesses are arranged in a circumferential direction, and the charged particle beam 1 passes through the plurality of stages 36a to 36f. Create a range of energy. The blades 37a, 37b, and 37c are arranged in angular ranges of 0 ° to 120 °, 120 ° to 240 °, and 240 ° to 360 ° (0 °), respectively. The six bases 36a, 36b, 36c, 36d, 36e, and 36f are each arranged in an angle range of 20 ° intervals. The RMW 35 is disposed in the beam path in the particle beam irradiation apparatus and rotates in a plane perpendicular to the beam path. For example, it is arranged upstream of the scanning irradiation system 34 shown in FIG.

  The principle that SOBP is formed by the RMW 35 will be described. For example, in a state where the RMW 35 is rotating, when the charged particle beam 1 passes through a thin portion of the blade (for example, the table 36f), the beam energy is less attenuated and the Bragg peak BP is generated deep inside the body. Further, when the charged particle beam 1 passes through a thick part of the blade (for example, the table 36a), the beam energy is greatly attenuated, and the Bragg peak BP is generated in a shallow part near the patient's body surface. Further, the rotation of the RMW 35 periodically changes the position of the Bragg peak BP. As a result of time integration, a broad flat dose distribution (SOBP) extending from a shallow portion near the body surface to the deep inside of the body. Can be obtained.

  By selecting a plurality of adjacent platforms and allowing the charged particle beam 1 to pass through only the selected platforms, a plurality of SOBP widths can be formed. For example, the SOBP width when the pedestals 36e and 36f are selected is assumed to be the SOBP width 1. Similarly to the SOBP width 1, when the bases 36d to 36f are selected, the bases 36c to 36f are selected, the bases 36b to 36f are selected, and the bases 36a to 36f are selected, the SOBP , The SOBP width 2, the SOBP width 3, the SOBP width 4, and the SOBP width 5. In the example of the RMW 35 shown in FIG. 10, when the base 36f is necessarily included, five SOBP widths can be formed and can be freely changed from the plurality of SOBP widths.

  The RMW 35 according to the present invention is used to expand the Bragg peak BP in the depth direction from the conventional spot and generate the columnar irradiation fields 44 and 45 (see FIG. 6). The particle beam irradiation apparatus according to the fifth embodiment has the configuration shown in FIG. That is, from the upstream side of the charged particle beam 1, the columnar irradiation field generation device 4, a set of scanning electromagnets 10 and 11, position monitors 12 a and 12 b, and a dose monitor 13 are provided and controlled by the irradiation control device 33. However, the columnar irradiation field generation device 4 is the depth direction irradiation field expansion device 3 (3c) provided with the RMW 35.

The columnar irradiation field generating device 4 according to the fifth embodiment includes an energy changing device 2 and a depth direction irradiation field expanding device 3 (3c). The depth direction irradiation field expansion device 3c will be described with reference to FIG. The depth direction irradiation field expansion device 3c includes an RMW 35, a rotation shaft 64 that rotates the RMW 35, a motor (rotation drive device) 62 that drives the rotation shaft 64, and an angle sensor 61 that detects the rotation angle of the rotation shaft 64. The irradiation field expansion control device 65 transmits a control signal Sig1 for controlling the start and stop of extraction of the charged particle beam 1 to the irradiation control device 33 based on the rotation angle detected by the angle sensor 61. The motor 62 and the rotating shaft 64 arranged at positions not interfering with the charged particle beam 1 are connected by bevel gears (connecting devices) 63a and 63b, for example. The irradiation field expansion control device 65 controls the rotation of the motor 62. Here, control is performed so that the RMW 35 continues to rotate at a predetermined constant speed. The RMW 35, the rotating shaft 64, the motor 62, the bevel gears (coupling devices) 63 a and 63 b, and the angle sensor 61 constitute an RMW device 66. The RMW device 66 changes the position of the RMW 35 through which the charged particle beam 1 passes to generate a width in energy. The irradiation field expansion control device 65 controls the charged particle beam 1 so as to pass through the plurality of stands 36a to 36f.

  The operation of the depth direction irradiation field expanding device 3c will be described. The case where the SOBP width in a certain columnar irradiation field 44 designated in the treatment plan is, for example, the SOBP width 4 will be described. The SOBP width 4 is formed when the charged particle beam 1 passes through an angle corresponding to the positions of the platforms 36b to 36f. The columnar irradiation field 44 is irradiated with the charged particle beam 1 in the columnar irradiation field 44 until the dose designated in the treatment plan expires (a target dose is reached). The charged particle beam 1 passes through the blade 37 provided with the platforms 36a to 36f at least once until the dose of the columnar irradiation field 44 expires. The RMW 35 is controlled to rotate in the direction indicated by the rotation direction 68 by the motor 62.

  The emission start of the charged particle beam 1 with respect to the columnar irradiation field 44 is performed by the angle sensor 61 with an angle region start angle of 20 ° (140 °, 260 °) being an emission start angle among the corresponding angles of 20 ° to 40 ° of the table 36b. To be detected. When the emission start angle is detected by the angle sensor 61, the irradiation field expansion control device 65 outputs the control signal Sig1 (for example, the first voltage level). In response to the control signal Sig1, the irradiation control device 33 issues an emission start instruction to the emission device of the accelerator so as to emit the charged particle beam 1 to the particle beam irradiation device 58. In response to the extraction start instruction, the accelerator emission device emits the charged particle beam 1 to the particle beam irradiation device 58 (beam emission procedure). Next, when the emission stop angle (120 °, 240 °, 360 ° (0 °)) is detected by the angle sensor 61, the irradiation field expansion control device 65 stops the control signal Sig1 (for example, to the second voltage level). Change). In response to the stop of the control signal Sig1, the irradiation control device 33 issues an extraction stop instruction to the extraction device of the accelerator so as to stop the charged particle beam 1 to the particle beam irradiation device 58. In response to the extraction stop instruction, the output device of the accelerator stops outputting the charged particle beam 1 to the particle beam irradiation device 58 (beam stop procedure).

  Next, the beam extraction procedure and the beam stop procedure are repeated for the next blade 37 until the dose expiration is detected by the dose monitor. When the expiration of the dose is detected by the dose monitor, the irradiation control device 33 receives the expiration of the dose and issues an extraction stop instruction to the extraction device of the accelerator so as to stop the charged particle beam 1 to the particle beam irradiation device 58. In response to the extraction stop instruction, the extraction device of the accelerator stops emitting the charged particle beam 1 to the particle beam irradiation device 58 (columnar irradiation field stop procedure). Thereafter, the procedure proceeds to the procedure for forming the next columnar irradiation field. The procedure for forming the columnar irradiation field is the above-described beam extraction procedure, beam stopping procedure, and columnar irradiation field stopping procedure.

  The particle beam irradiation apparatus 58 having the depth direction irradiation field expanding apparatus 3c of the fifth embodiment has a columnar irradiation field in which the Bragg peak of the charged particle beam is expanded to a depth corresponding to the distal shape of the irradiation target. Therefore, it is possible to increase the degree of freedom of irradiation in the depth direction without using a bolus, and to solve the IMRT over-irradiation problem in the particle beam therapy system.

  The RMW 35 has an advantageous effect not found in the ridge filter. As shown in FIG. 6, depending on the shape of the affected part 40, the columnar irradiation field 45 in the second round may need to change the width of the columnar irradiation field 44 in the first round and the SOBP. When changing the width of SOBP using a ridge filter, it is necessary to prepare a plurality of ridge filters as shown in FIGS. On the other hand, in the case of RMW, the width of the SOBP can be freely changed by controlling the start and stop of extraction of the charged particle beam 1 based on the rotation angle of the RMW 35. That is, as described above, the width of the SOBP can be freely controlled by one RMW 35 by synchronizing the rotation of the RMW 35 and the beam emission timing. Therefore, when forming the width | variety of several SOBP, the structure of the columnar irradiation field production | generation apparatus 4 can be simplified.

Embodiment 6 FIG.
FIG. 12 is a block diagram showing a depth direction irradiation field enlarging apparatus according to Embodiment 6 of the present invention. It differs from the depth direction irradiation field expansion device 3c of the fifth embodiment in that it has a plurality of RMW devices having different selectable SOPB widths. The depth direction irradiation field expanding device 3d shown in FIG. 12 is an example having two RMW devices 66a and 66b. The RMW 35a of the RMW device 66a is an example in which the number of selectable SOPB widths is larger than that of the RMW 35b of the RMW device 66b. The irradiation field expansion control device 65 selects which of the RMW device 66a and the RMW device 66b is used, and also controls the drive device 67a that drives the RMW device 66a and the drive device 67b that drives the RMW device 66b. The irradiation field expansion control device 65 receives the signal of the angle sensor 61 of the RMW device 66a and the signal of the angle sensor 61 of the RMW device 66b, and outputs or stops the control signal Sig1.

  Increasing the number of selectable SOPB widths can be achieved by increasing the number of blades 36. For example, the RMW 35a has two blades 37a and 37b, and each blade 37a and 37b has nine bases 36a to 36i. In this case, the angle range of each blade is 180 °, and the angle range of each stand is 20 ° as in the fifth embodiment. Note that only one blade 37 may be used, and the thicknesses of the bases 36 of the RMW 35 may all be different. Also in the embodiment to which the RMW 35 is applied, all the thicknesses of the bases 36 of the RMW 35 may be different.

  Since the depth direction irradiation field expansion device 3d of the sixth embodiment includes a plurality of RMW devices 66a and 66b having different selectable SOPB widths, it is wider than the depth direction irradiation field expansion device 3c of the fifth embodiment. A range of SOPB widths can be formed. Therefore, the particle beam irradiation apparatus 58 having the depth direction irradiation field expanding apparatus 3d can form and irradiate more types of columnar irradiation fields than the particle beam irradiation apparatus 58 of the fifth embodiment, and can efficiently irradiate the affected part 40. Multi-gate irradiation can be performed.

Embodiment 7 FIG.
FIG. 13: is a block diagram which shows the columnar irradiation field production | generation apparatus by Embodiment 7 of this invention. The columnar irradiation field generation device 4a having the depth direction irradiation field expansion device 3c according to the fifth embodiment is different in that the energy changing device 2 (2a) and the depth direction irradiation field expansion device 3c are integrated.

  The columnar irradiation field generation device 4c includes two range shifters 9a and 9b, two RMW devices 66a and 66b, and upstream deflection that moves the position where the charged particle beam 1 passes through the range shifters 9a and 9b and the RMW devices 66a and 66b. The charged particle beam 1 that has passed through the deflection electromagnets 5 and 6 constituting the electromagnet pair, the first deflection electromagnet power source 20 that excites the upstream side deflection electromagnet pair, the range shifters 9a and 9b, and the RMW devices 66a and 66b is placed on the original trajectory. Based on the energy command value input from the deflection electromagnets 7 and 8 constituting the returning downstream deflection electromagnet pair, the second deflection electromagnet power source 21 for exciting the downstream deflection electromagnet pair, and the irradiation control device 33, the upstream deflection electromagnet pair. A change control device 30 is provided that calculates the amount of movement of the charged particle beam trajectory by means of and transmits the exciting current value to the first deflection electromagnet power source 20.The change control device 30 also controls the second bending electromagnet power source 21. The change control device 30 also has the function of the irradiation field expansion control device 65 of the fifth embodiment. The range shifter 9a is arranged on the upstream side of the RMW device 66a so as to be located in a range from the rotation shaft 64a of the RMW 35a to the outer periphery of the RMW 35a. The range shifter 9b is disposed on the upstream side of the RMW device 66b so as to be located in a range from the rotation shaft 64b of the RMW 35b to the outer periphery of the RMW 35b. Since the operation of each device is the same as in the first and fifth embodiments, it will not be repeated.

  The range shifters 9a and 9b are of the same shape and material, and the RMW 35a of the RMW device 66a and the RMW 35b of the RMW device 66b are examples in which the widths of selectable SOPBs are different. As described in Embodiment 6, the RMW 35a of the RMW device 66a can have a larger number of selectable SOPB widths than the RMW 35b of the RMW device 66b.

  Since the columnar irradiation field generation device 4c according to the seventh embodiment includes a plurality of RMW devices 66a and 66b having different selectable SOPB widths, the columnar irradiation field generation device 4c has a wider range than the depth direction irradiation field expansion device 3c according to the fifth embodiment. The width of SOPB can be formed. Therefore, the particle beam irradiation apparatus 58 having the columnar irradiation field generation device 4c can form and irradiate more types of columnar irradiation fields than the particle beam irradiation apparatus 58 of the fifth embodiment, and can efficiently irradiate the affected area 40. Multi-gate irradiation can be performed.

  The columnar irradiation field generation device 4c according to the seventh embodiment can be controlled not to repeat the emission and stop of the charged particle beam 1 when forming the columnar irradiation fields 44 and 45. For convenience, the columnar irradiation field generation device of this example will be referred to as a columnar irradiation field generation device 4d in order to distinguish it from the columnar irradiation field generation device 4c described above. By not repeating the emission and stop of the charged particle beam 1 when forming the columnar irradiation fields 44 and 45, it is possible to perform the irradiation of the charged particle beam 1 suitable for respiratory synchronization irradiation. For example, the number of the bases 36 of the RMW 35a is the same as that described in the sixth embodiment, and the number of the bases 36 of the RMW 35b is the same as that described in the fifth embodiment. When the columnar irradiation fields 44 and 45 are formed, the charged particle beam 1 is allowed to pass through the platform 36 of the RMW 35a or RMW 35b until the dose has expired. Thus, there is one kind of SOBP width (SOBP width a) when the charged particle beam 1 passes through the RMW 35a, and one kind of SOBP width (SOBP width b) when the charged particle beam 1 passes through the RMW 35b. is there. Moreover, the SOBP width b can be wider than the SOBP width a. When the columnar irradiation fields 44 and 45 are formed without necessarily repeating the emission and stop of the charged particle beam 1, the change control device 30 does not need to generate the control signal Sig1, and therefore the change control device 30. The configuration can be simplified.

  Since the columnar irradiation field generation device 4d according to the seventh embodiment changes the charged particle beam 1 to the desired energy with the widths of the two types of SOBP, the two types of the shot irradiation field can be set to the desired range. . By not repeating the emission and stop of the charged particle beam 1 when forming the columnar irradiation fields 44 and 45, it is possible to perform the irradiation of the charged particle beam 1 suitable for respiratory synchronization irradiation. In order to make the widths of many types of SOBP more than two types uniform, the range shifter 9 and the RMW device 66 corresponding to the number of types may be arranged.

  The columnar irradiation field generation devices 4c and 4d according to the seventh embodiment do not provide upstream deflection electromagnet pairs and downstream deflection electromagnet pairs for the range shifters 9a and 9b and the RMW devices 66a and 66b, respectively. Since only one set of electromagnet pair and downstream deflection electromagnet pair is provided, the length of the apparatus in the irradiation direction (Z direction) of the charged particle beam 1 is shorter than that of the columnar irradiation field generation apparatus 4a of the first embodiment. it can.

  The particle beam irradiation apparatus (see FIG. 1) having the columnar irradiation field generation apparatuses 4c and 4d according to the seventh embodiment is based on a treatment plan corresponding to the treatment plan created by the treatment planning apparatus shown in the first embodiment. Since irradiation can be executed, the degree of freedom in irradiation in the depth direction can be increased without using a bolus as in the first embodiment, and the IMRT over-irradiation problem in the particle beam therapy system can be solved.

Embodiment 8 FIG.
Up to now, the particle beam irradiation apparatus described in the first to seventh embodiments has been described with an example in which the energy of the charged particle beam 1 is changed in the columnar irradiation field generation apparatus 4. However, the change of the energy of the charged particle beam 1 can also be realized by changing the parameters of the synchrotron 54. Here, an example in which the columnar irradiation fields 44 and 45 are generated by combining the parameters of the synchrotron 54 and the depth direction irradiation field expanding device 3 will be described. FIG. 14 is a block diagram showing a particle beam irradiation apparatus according to Embodiment 8 of the present invention. The particle beam irradiation apparatus 60 of the eighth embodiment differs from the particle beam irradiation apparatus shown in the first to seventh embodiments in the synchrotron 54 even if the columnar irradiation field generating apparatus 4 is not provided with the energy changing device 2. The difference is that the energy of the charged particle beam 1 is changed to generate the columnar irradiation fields 44 and 45.

  The columnar irradiation field generation device 4 (4e) of the particle beam irradiation device 60 includes a depth direction irradiation field expansion device 3. The depth direction irradiation field expansion device 3 is one of the above-described depth direction irradiation field expansion devices 3a, 3b, 3c, and 3d. When forming the columnar irradiation fields 44 and 45, the irradiation control device 33 sets the energy command value to the synchrotron as an accelerator so that the columnar irradiation fields 44 and 45 planned in the treatment plan are positioned in the depth direction. Output to TRON 54. The synchrotron 54 receives the energy command value and changes the energy of the charged particle beam 1 according to the energy command value. The charged particle beam 1 having a predetermined energy enters the particle beam irradiation apparatus 60 through the ion beam transport system 59. In the columnar irradiation field generation device 4 (4e), the width of the energy of the charged particle beam 1 is changed so as to have a predetermined SOBP width planned in the treatment plan, and a predetermined position of the affected part 40 is set at a predetermined position. Columnar irradiation fields 44 and 45 are formed.

  Since the particle beam irradiation apparatus 60 of the eighth embodiment can execute multi-port irradiation based on the treatment plan corresponding to the treatment plan created by the treatment planning apparatus shown in the first embodiment, as in the first embodiment, The degree of freedom of irradiation in the depth direction can be increased without using a bolus, and the IMRT over-irradiation problem in the particle beam therapy system can be solved. Moreover, the particle beam irradiation apparatus 60 has the effect of the depth direction irradiation field expansion apparatuses 3a, 3b, 3c, and 3d applied to the columnar irradiation field generation apparatus 4 (4e).

Embodiment 9 FIG.
The ninth embodiment of the present invention is a particle beam therapy system provided with the particle beam irradiation apparatus described in the first to eighth embodiments. FIG. 15 is a schematic configuration diagram of a particle beam therapy system according to Embodiment 9 of the present invention. The particle beam treatment apparatus 51 includes an ion beam generation apparatus 52, an ion beam transport system 59, and particle beam irradiation apparatuses 58a and 58b (60a and 60b). The ion beam generator 52 includes an ion source (not shown), a pre-accelerator 53, and a synchrotron 54. The particle beam irradiation device 58b is installed in a rotating gantry (not shown). The particle beam irradiation device 58a is installed in a treatment room having no rotating gantry. The role of the ion beam transport system 59 is in communication between the synchrotron 54 and the particle beam irradiation devices 58a and 58b. A part of the ion beam transport system 59 is installed in a rotating gantry (not shown), and the part has a plurality of deflection electromagnets 55a, 55b, and 55c.

  A charged particle beam, which is a particle beam such as a proton beam generated by an ion source, is accelerated by the pre-stage accelerator 53 and is incident on the synchrotron 54. The charged particle beam is accelerated to a predetermined energy. The charged particle beam emitted from the synchrotron 54 is transported to the particle beam irradiation devices 58a and 58b (60a and 60b) through the ion beam transport system 59. The particle beam irradiation devices 58a and 58b (60a and 60b) irradiate a patient's affected part (not shown) with a charged particle beam.

  The particle beam treatment apparatus 51 of the ninth embodiment operates the particle beam irradiation apparatus 58 (60) based on the treatment plan created by the treatment planning apparatus shown in the first embodiment, and applies the charged particle beam to the affected area of the patient. Therefore, the IMRT over-irradiation problem in the particle beam therapy system can be solved by increasing the degree of freedom of irradiation in the depth direction without using a bolus.

  The particle beam therapy system 51 according to the ninth embodiment irradiates the beam with a columnar dose distribution, and therefore has an advantage that the irradiation time is shorter than that in the point irradiation. In addition, since multiportal irradiation is possible, when the same affected area is irradiated, damage to the body surface, which is a normal tissue, can be reduced, and irradiation to a dangerous site (spinal cord, eyeball, etc.) that should not be irradiated can be avoided.

  Furthermore, the particle beam therapy system 51 of the ninth embodiment has an advantage that multi-port irradiation can be performed remotely. Remote multi-port irradiation means that a technician or the like does not need to enter a treatment room and operate a rotating gantry, and remotely irradiates a particle beam by changing the irradiation direction to an affected area in multiple directions from outside the treatment room. As described above, the particle beam therapy system according to the present invention is a simple irradiation system that does not require an MLC or a bolus, so that a bolus replacement operation and an MLC shape confirmation operation are not required. As a result, remote multi-port irradiation can be performed, and the effect that treatment time is significantly shortened can be obtained.

  In the columnar irradiation field generating device 4 having the energy changing device 2 and the depth direction irradiation field expanding device 3, the columnar irradiation field generating device 4 is shown in the energy changing device 2b and the third embodiment shown in the second embodiment. The depth direction irradiation field expanding device 3b can also be used.

  Up to now, in the fifth to seventh embodiments, the depth direction irradiation field enlarging apparatus rotates the RMW 35 at a predetermined constant speed, and emits the charged particle beam 1 so that only the selected stage passes the charged particle beam 1. In the example described above, the emission stop is repeated to form a plurality of SOBP widths. There are other methods for forming a plurality of SOBP widths using the RMW 35. For example, the case where the bases 36e and 36f form the SOBP width 1 that is the width of the selected SOBP will be described. As the motor 62, a servo motor or a stepping motor is used. Irradiation of the charged particle beam 1 is started at a position where the charged particle beam 1 passes through the table 36f. After a certain period of time, the charged particle beam 1 is moved to a position where the motor passes through the table 36e. After a certain period of time, the charged particle beam 1 is set to a position where it passes through the table 36f. The SOBP width 1 can be formed by changing the positions of the bases 36e and 36f so as to reciprocate every predetermined time. When the bases 36a to 36f form the SOBP width 5 that is the width of the selected SOBP, the positions of the bases 36a to 36f may be changed so as to reciprocate every predetermined time. Alternatively, the charged particle beam 1 may be stopped every time a certain time elapses, and then the position of the table 36 through which the charged particle beam 1 passes may be changed, and the charged particle beam 1 may be emitted after this change. When changing so that the position of the bases 36a-36f can reciprocate without stopping the charged particle beam 1, it is applicable also to respiration synchronous irradiation.

  The particle beam irradiation apparatus and particle beam therapy apparatus according to the present invention can be suitably used in medicine. In particular, it can solve the problem of IMRT that causes excessive irradiation and contributes to the development of the medical industry.

DESCRIPTION OF SYMBOLS 1 ... Charged particle beam, 2, 2a, 2b ... Energy change device 3, 3a, 3b, 3c, 3d ... Depth direction irradiation field expansion device 4, 4a, 4b, 4c, 4d, 4e ... Columnar irradiation field production | generation Device 5, 6, 7, 8 ... deflection magnet 9, 9, 9a, 9b ... range shifter, 14 ... beam axis, 15, 16, 17, 18 ... deflection magnet, 19, 19a, 19b ... ridge filter, 22 ... change control Device, 25 ... Irradiation field expansion control device, 26a, 26b, 26c, 26d ... Absorber, 27a, 27b, 27c, 27d ... Drive device, 28a, 28b, 28c, 28d ... Ridge filter, 29a, 29b, 29c, 29d ... drive device, 30 ... change control device, 34 ... scanning irradiation system, 35 ... RMW (range modulation wheel), 36a, 36b, 36c, 36d, 36e, 36f ... stand, 7a, 37b, 37c ... blades (energy absorber), 40 ... affected part, 44a, 44b, 44c, 44d, 45a, 45b, 45c, 45d ... columnar irradiation field, 52 ... ion beam generator, 54 ... synchrotron, 58 58a, 58b ... particle beam irradiation device, 59 ... ion beam transport system, 60, 60a, 60b ... particle beam irradiation device, 61 ... angle sensor, 62 ... motor, 65 ... irradiation field expansion control device, 66, 66a, 66b ... RMW devices, 67a, 67b ... Drive devices

Claims (11)

An X-direction scanning magnet that scans the charged particle beam accelerated by the accelerator in the X-direction and Y-direction perpendicular to the irradiation direction, and a scanning irradiation system that scans in the X-direction and the Y-direction by the Y-direction scanning magnet, and A treatment planning apparatus for creating a treatment plan for a particle beam therapy apparatus including a columnar irradiation field generation device that expands a Bragg peak of a charged particle beam and generates a columnar irradiation field,
The columnar irradiation field is the width of the SOBP in which the height of the columnar irradiation field is the width in the irradiation direction of the charged particle beam, and the length of the cross section perpendicular to the axis in the height direction of the columnar irradiation field. Is the beam size that is the width of the charged particle beam in the X direction and the Y direction, and is the beam size of the charged particle beam that has not been forcibly expanded since being emitted from the accelerator , The height of the columnar irradiation field is an irradiation field longer than the beam size,
The beam size is a single size selected in a single treatment irradiation,
According to the distal shape of the irradiation target irradiated with the charged particle beam, the outer columnar irradiation field that is the columnar irradiation field having the width of one SOBP is arranged, and the outer columnar shape is disposed inside the irradiation target. An irradiation field arrangement part that lays out and arranges an inner columnar irradiation field that is the columnar irradiation field having a width of the SOBP different from the irradiation field so as to overlap an inner end of the outer columnar irradiation field;
The state where the outer columnar irradiation field and the inner columnar irradiation field are spread by the irradiation field arrangement unit is set as an initial state, and the outer columnar irradiation field and the inner side are set so that the irradiation dose to the irradiation target falls within a predetermined range. A treatment planning apparatus having an optimization calculation unit for adjusting the arrangement of columnar irradiation fields. An X-direction scanning magnet that scans the charged particle beam accelerated by the accelerator in the X-direction and Y-direction perpendicular to the irradiation direction, and a scanning irradiation system that scans in the X-direction and the Y-direction by the Y-direction scanning magnet, and A treatment planning apparatus for creating a treatment plan for a particle beam therapy apparatus including a columnar irradiation field generation device that expands a Bragg peak of a charged particle beam and generates a columnar irradiation field,
The columnar irradiation field is the width of the SOBP in which the height of the columnar irradiation field is the width in the irradiation direction of the charged particle beam, and the length of the cross section perpendicular to the axis in the height direction of the columnar irradiation field. Is the beam size that is the width of the charged particle beam in the X direction and the Y direction, and is the beam size of the charged particle beam that has not been forcibly expanded since being emitted from the accelerator. Thus, the height of the columnar irradiation field is longer than the beam size,
The beam size is a single size selected in a single treatment irradiation,
According to the distal shape of the irradiation target irradiated with the charged particle beam, the outer columnar irradiation field that is the columnar irradiation field having the width of one SOBP is arranged, and the outer columnar shape is disposed inside the irradiation target. An irradiation field arrangement section for arranging and arranging an inner columnar irradiation field that is the columnar irradiation field having a width of the other SOBP smaller than the irradiation field so as to overlap an inner end of the outer columnar irradiation field;
The state where the outer columnar irradiation field and the inner columnar irradiation field are spread by the irradiation field arrangement unit is set as an initial state, and the outer columnar irradiation field and the inner side are set so that the irradiation dose to the irradiation target falls within a predetermined range. A treatment planning apparatus having an optimization calculation unit for adjusting the arrangement of columnar irradiation fields.   The irradiation field arrangement unit arranges the outer columnar irradiation field in accordance with the distal shape of the irradiation target, and then performs the inner columnar irradiation in accordance with an inner shape in which the outer columnar irradiation field in the irradiation target is not disposed. The treatment planning apparatus according to claim 1, wherein a field is arranged. An ion beam generator for generating a charged particle beam and accelerating it to a predetermined energy by an accelerator, an ion beam transport system for transporting a charged particle beam accelerated by the ion beam generator, and transported by the ion beam transport system A particle beam treatment apparatus comprising: a particle beam irradiation apparatus that irradiates an irradiation target with the charged particle beam; and a rotating gantry that rotates an irradiation direction of the particle beam irradiation apparatus,
The particle beam irradiation apparatus includes an X-direction scanning magnet and a Y-direction scanning magnet that scan a charged particle beam accelerated by the accelerator in an X direction and a Y direction perpendicular to the irradiation direction, respectively, in the X direction and the Y direction. A scanning irradiation system for scanning, and a columnar irradiation field generating device for expanding a Bragg peak of the charged particle beam and generating a columnar irradiation field,
4. A particle beam therapy apparatus according to claim 1, wherein a therapy planning apparatus for creating a therapy plan for the particle beam therapy apparatus is the therapy planning apparatus according to claim 1. An ion beam generator for generating a charged particle beam and accelerating it to a predetermined energy by an accelerator, an ion beam transport system for transporting a charged particle beam accelerated by the ion beam generator, and transported by the ion beam transport system A particle beam treatment apparatus comprising: a particle beam irradiation apparatus that irradiates an irradiation target with the charged particle beam; and a rotating gantry that rotates an irradiation direction of the particle beam irradiation apparatus,
The particle beam irradiation apparatus includes an X-direction scanning magnet and a Y-direction scanning magnet that scan a charged particle beam accelerated by the accelerator in an X direction and a Y direction perpendicular to the irradiation direction, respectively, in the X direction and the Y direction. A scanning irradiation system for scanning, and a columnar irradiation field generating device for expanding a Bragg peak of the charged particle beam and generating a columnar irradiation field,
The scanning irradiation system includes:
1st irradiation which irradiates so that the said outside columnar irradiation field may be arrange | positioned according to the distal shape of the said irradiation object based on the treatment plan created by the treatment plan apparatus of any one of Claim 1 to 3 And a second irradiation for irradiating the inner columnar irradiation field so as to be arranged inside the outer columnar irradiation field.   6. The particle beam therapy system according to claim 5, wherein the scanning irradiation system performs the first irradiation and performs the second irradiation after the first irradiation. The columnar irradiation field generation device includes: an energy changing device that changes energy of the charged particle beam; and a depth direction irradiation field expanding device that expands a Bragg peak of the charged particle beam. The particle beam therapy apparatus according to any one of 4 to 6. The energy changing device is:
A range shifter in which the thickness in the direction in which the charged particle beam passes varies depending on the location and reduces the energy of the charged particle beam passing through the thickness, and an upstream side that moves the passing position of the charged particle beam in the range shifter A deflection electromagnet pair, a downstream deflection electromagnet pair for returning the trajectory of the charged particle beam toward the beam axis incident on the energy changing device, and the charged particle beam so as to pass a predetermined thickness of the range shifter The particle beam therapy system according to claim 7, further comprising an upstream deflection electromagnet pair and a change control device that controls the downstream deflection electromagnet pair. The depth direction irradiation field expanding device is:
A ridge filter having a thickness distribution in which energy lost depending on a position through which the charged particle beam passes, an upstream deflection electromagnet pair that moves a passing position of the charged particle beam in the ridge filter, and a trajectory of the charged particle beam A downstream deflecting electromagnet pair returning toward the beam axis incident on the depth direction irradiation field enlarging device, the upstream deflecting electromagnet pair so that the charged particle beam passes through a predetermined thickness distribution of the ridge filter, and The particle beam therapy system according to claim 7, further comprising an irradiation field expansion control device that controls the downstream deflection electromagnet pair. The energy changing device is:
A plurality of absorbers whose energy is reduced by the thickness through which the charged particle beam passes; a plurality of drive devices for driving each of the absorbers; and the absorption through which the charged particle beam passes by driving the drive device The particle beam therapy system according to claim 7, further comprising a change control device that controls a total thickness of the body. The depth direction irradiation field expanding device is:
A plurality of ridge filters that change the width of energy according to the thickness through which the charged particle beam passes, a plurality of drive devices that drive each of the ridge filters, and the charged particle beam that passes through the drive device. The particle beam therapy system according to claim 7, further comprising an irradiation field expansion control device that controls a total thickness of the ridge filter.

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