JP2019136167A - Particle beam irradiation device - Google Patents

Abstract

To provide a particle beam irradiation device capable of expanding a Bragg peak width smoothly even when a Bragg peak is extremely thin and sharp, and forming uniform total dose distribution easily.SOLUTION: A particle beam irradiation device 50 includes an irradiation system 6 for irradiating an irradiation object 11 with a particle beam 10 transported from a particle beam generation and transport device 1. The irradiation system 6 includes a Bragg peak expansion filter 17 for decomposing the particle beam 10 into a plurality of particle beam components with different energies, and expanding the width in a depth direction of the Bragg peak in the irradiation object 11 by the decomposed particle beam components. The Bragg peak expansion filter 17 includes a first material part 18 having a thickness in a direction parallel to a beam axis 9, and a plurality of hole parts 19 disposed on a surface of the first material part 18 perpendicular to the beam axis 9, which penetrate in a direction parallel to the beam axis 9 or are recessed in a direction parallel to the beam axis 9.SELECTED DRAWING: Figure 1

Description

  The present application relates to a particle beam irradiation apparatus that performs particle beam therapy by irradiating an affected area such as a tumor with a particle beam (charged particle beam).

  Particle beam therapy uses a device such as an accelerator to accelerate charged particles such as protons or carbon ions to several hundred mega-electron volts, and irradiates the patient with a dose to the tumor (affected area) that is the target of irradiation in the body. It is a method of giving and treating cancer. At this time, it is important to form a dose distribution instructed by the doctor, that is, a dose distribution as close as possible to the target distribution for the tumor. In many cases, the target distribution is such that the dose is uniform within the tumor and is as low as possible outside the tumor than inside the tumor.

  In general, when an object (including a human body) is irradiated with a particle beam accelerated by an accelerator, the three-dimensional dose distribution in the object has a characteristic that has a maximum dose peak at one point. This maximum dose peak is called the Bragg peak. In addition, when there is a maximum dose peak at one point in the three-dimensional space, the peak position is defined as the “irradiation position” of the particle beam. In order to form the target distribution three-dimensionally using the particle beam having the peak structure as described above, some device is required.

  There are roughly two types of irradiation methods in the particle beam irradiation apparatus. In the first irradiation method, a particle beam is scattered by a scatterer to be enlarged, an irradiation field is formed by matching the expanded particle beam with the shape of the irradiation target, and the beam is applied to the entire affected area of the patient who is the irradiation target. Broad irradiation method that irradiates all at once. The second irradiation method is a scanning irradiation method (spot scanning method, raster scanning method, etc.) in which a thin pencil beam is scanned to an arbitrary position by a scanning electromagnet so as to match the shape of the irradiation target. . Among the several broad irradiation methods, the wobbler method, in which the particle beam is simultaneously rotated in the X and Y directions by a rotating magnetic field to flatten the irradiation field, is generated by two wobbler electromagnets in the X and Y directions. Are scanned at high speed along a circular orbit.

  In the broad irradiation method, a ridge filter that expands the width of the Bragg peak according to the thickness of an irradiation target (affected part) is generally used (for example, Patent Document 1). Japanese Patent Application Laid-Open No. 2004-228561 describes problems of the conventional ridge filter.

Japanese Unexamined Patent Publication No. 2003-255093 (stage 0022 to stage 0023, FIG. 9)

  When each wedge-shaped element of a ridge filter having a plurality of wedge-shaped elements has 20 or more steps, the particle beam components having different energies according to the number of steps passing through the ridge filter cause the body to enter the body. A high total dose distribution with high dose is obtained. However, when the number of step portions of each wedge-shaped element is reduced, it is pointed out in Patent Document 1 that although the ridge filter can be easily manufactured, the total amount distribution in the depth direction in the body becomes non-uniform. Has been. That is, in the conventional particle beam irradiation apparatus, when the Bragg peak is extremely thin and sharp, a very sophisticated ridge filter is required to smoothly expand the Bragg peak width.

  The present application discloses a technique for solving the above-described problems, and even when the Bragg peak is extremely thin and sharp, it is possible to smoothly expand the Bragg peak width and easily form a uniform total dose distribution. It aims at providing a beam irradiation apparatus.

  The particle beam irradiation apparatus disclosed in the present application includes a particle beam generation and transport apparatus that generates and transports accelerated particle beams, an irradiation system that irradiates the irradiation target with the particle beams transported from the particle beam generation and transport apparatus, and It has. The irradiation system consists of a scanning device that deflects the particle beam in two directions perpendicular to the beam axis of the transported particle beam, and decomposes the particle beam into a plurality of particle beam components having different energies. And a Bragg peak expansion filter that expands the width in the depth direction of the Bragg peak in the irradiation target. A plurality of Bragg peak expansion filters are arranged on the surface of the first material part having a thickness in a direction parallel to the beam axis and the first material part perpendicular to the beam axis, and penetrates in the direction parallel to the beam axis. Or a hole recessed in a direction parallel to the beam axis.

  Since the particle beam irradiation apparatus disclosed in the present application includes the Bragg peak expansion filter in which a plurality of hole portions penetrating or recessed in the surface of the first material portion is provided, the Bragg peak is extremely thin and sharp. However, the Bragg peak width can be expanded smoothly and a uniform total dose distribution can be easily formed.

1 is a schematic configuration diagram of a particle beam irradiation apparatus according to Embodiment 1. FIG. It is a perspective view which shows the 1st example of the Bragg peak expansion filter of FIG. FIG. 3 is a front view of the Bragg peak widening filter of FIG. It is a figure explaining the energy component of the particle beam after passing the Bragg peak expansion filter of FIG. It is a figure which shows the energy component of the particle beam after passing through the ridge filter of a 1st comparative example. It is a figure which shows dose distribution of a 1st comparative example. It is a figure which shows dose distribution of a 2nd comparative example. It is a figure which shows the example of the energy frequency distribution of the particle beam by the particle beam irradiation apparatus of FIG. It is a figure which shows dose distribution corresponding to the energy frequency distribution of the particle beam of FIG. 6 is a front view showing a second example of the Bragg peak widening filter according to Embodiment 1. FIG. 6 is a front view showing a third example of the Bragg peak widening filter according to Embodiment 1. FIG. 6 is a front view showing a fourth example of the Bragg peak widening filter according to Embodiment 1. FIG. 6 is a front view showing a fifth example of the Bragg peak widening filter according to Embodiment 1. FIG. 6 is a front view showing a sixth example of the Bragg peak widening filter according to Embodiment 1. FIG. 10 is a front view showing a seventh example of the Bragg peak widening filter according to Embodiment 1. FIG. 10 is a front view showing an eighth example of a Bragg peak widening filter according to Embodiment 1. FIG. 10 is a front view showing a ninth example of the Bragg peak widening filter according to Embodiment 1. FIG. It is sectional drawing of AA in FIG. It is a figure explaining the energy component of the particle beam after passing the Bragg peak expansion filter of FIG. It is a front view which shows the 10th example of the Bragg peak expansion filter by Embodiment 1. It is a front view which shows the 1st filter element of FIG. It is a front view which shows the 2nd filter element of FIG. FIG. 21 is a front view showing a third filter element of FIG. 20. FIG. 21 is a front view of a hole viewed from the upstream side of the beam axis in the Bragg peak widening filter of FIG. 20. It is a figure explaining the energy component of the particle beam after passing the Bragg peak expansion filter of FIG. It is a front view which shows the 11th example of the Bragg peak expansion filter by Embodiment 1. FIG. 27 is a front view showing the first filter element of FIG. 26. FIG. 27 is a front view showing a second filter element of FIG. 26. FIG. 27 is a front view showing a third filter element of FIG. 26. FIG. 27 is a front view showing a fourth filter element of FIG. 26. FIG. 27 is a front view of a hole viewed from the upstream side of the beam axis in the Bragg peak widening filter of FIG. 26. It is a front view which shows the 12th example of the Bragg peak expansion filter by Embodiment 1. It is a schematic block diagram of the particle beam irradiation apparatus by Embodiment 2. It is a flowchart which shows operation | movement of the particle beam irradiation apparatus of FIG. It is a figure which shows the example of the energy frequency distribution of the particle beam by the particle beam irradiation apparatus of a comparative example. It is a figure which shows dose distribution corresponding to the energy frequency distribution of the particle beam of FIG. It is a figure which shows the example of the energy frequency distribution of the particle beam by the particle beam irradiation apparatus of FIG. It is a figure which shows dose distribution corresponding to the energy frequency distribution of the particle beam of FIG. It is a figure explaining the principal part of the particle beam irradiation apparatus by Embodiment 3. FIG. It is sectional drawing of the 1st filter part of FIG. It is a figure explaining the energy component of the particle beam after passing the 1st filter part of FIG. It is a figure which shows the example of dose distribution by the 1st filter part of FIG. It is sectional drawing of the 2nd filter part of FIG. It is a figure explaining the energy component of the particle beam after passing through the 2nd filter part of FIG. It is a figure which shows the example of the dose distribution by the 2nd filter part of FIG. It is a figure explaining the principal part of the other particle beam irradiation apparatus by Embodiment 3. FIG. It is sectional drawing of the 3rd filter part of FIG. It is a figure explaining the energy component of the particle beam after passing through the 3rd filter part of FIG. It is a figure which shows the example of dose distribution by the 3rd filter part of FIG.

Embodiment 1 FIG.
FIG. 1 is a schematic configuration diagram of a particle beam irradiation apparatus according to the first embodiment. 2 is a perspective view showing a first example of the Bragg peak widening filter of FIG. 1, and FIG. 3 is a front view of the Bragg peak widening filter of FIG. 2 viewed from the upstream side of the beam axis. FIG. 4 is a diagram for explaining the energy component of the particle beam after passing through the Bragg peak expansion filter of FIG. The particle beam irradiation apparatus 50 of Embodiment 1 is an example which performs broad irradiation by a broad irradiation method. The particle beam irradiation apparatus 50 according to the first embodiment accelerates charged particles to necessary energy, generates accelerated charged particles as particle beams 10, and transports them to the irradiation system 6. An irradiation system 6 that irradiates the irradiation target 11 of the patient 13 with the particle beam 10 so as to form an irradiation field, a scheduled dose value of the particle beam 10 to be irradiated to the irradiation target 11, and scanning speed information of the scanning device 2 are stored. And a control unit 4 that controls the start and block of emission of the particle beam 10 by the particle beam generation and transport device 1 and the scanning of the particle beam 10 by the scanning device 2.

  The irradiation system 6 has two directions perpendicular to the Z direction, which is the beam traveling direction (beam axis direction) in which the particle beam travels from the upstream side to the downstream side of the particle beam 10 generated by the particle beam generating and transporting device 1. That is, a scanning device 2 having an X-direction scanning device 23 and a Y-direction scanning device 24 that deflects in the X and Y directions and scans the particle beam 10 in a circular orbit, for example, a scatterer 25, and a Bragg peak expansion filter 17, a ridge filter 26, a range shifter 27, a dose monitor 5 that measures a dose value irradiated to the irradiation object 11 by the particle beam 10, a multi-leaf collimator 28, and a bolus (compensation filter) 29. The scatterer 25 is made of lead or the like and scatters the particle beam 10. The Bragg peak expansion filter 17 decomposes the particle beam 10 into a plurality of particle beam components having different energies, and expands the Bragg peak in the irradiation target 11 by the plurality of decomposed particle beam components. The ridge filter 26 is made of aluminum or the like, and expands the width of the Bragg peak of the particle beam 10 according to the thickness of the irradiation target 11. The range shifter 27 changes the energy of the particle beam 10 and changes the range of the particle beam 10. The range shifter 27 has a plurality of transmission units (not shown) with different thicknesses, and changes the total thickness of the transmission units by moving the transmission units, thereby reducing the energy of the particle beam 10 and changing it. The beam axis 9 is an axis along which the particle beam 10 travels when the particle beam 10 is not deflected by the X direction scanning device 23 and the Y direction scanning device 24. The beam axis 9 is an axis that passes through an isocenter (not shown), which is a reference for irradiating the particle beam 10. When the irradiation system 6 is mounted on the rotating gantry, the intersection of the rotating axis of the rotating gantry and the beam axis 9 of the particle beam 10 is an isocenter.

  The multi-leaf collimator 28 is configured by a leaf driving mechanism that drives each of a leaf portion composed of a plurality of leaf plates and a leaf plate, and irradiates an irradiation field (planar shape) perpendicular to the beam axis 9 of the particle beam 10 on the irradiation target 11. Adjust to fit the shape. The bolus (compensation filter) 29 adjusts the energy of the particle beam 10 so as to match the depth shape (distal shape) of the irradiation object 11. The ridge filter 26 is formed into a shape in which, for example, a large number of conical bodies and triangular plates having a triangular cross section are arranged in the plane direction, so that there are particle beams 10 that pass through different thicknesses for each divided region in the plane direction. It has become. In FIG. 1, for easy understanding, triangular prisms (wedge-shaped elements) are illustrated as being arranged sideways. When a plurality of particle beam components having different energies decomposed by the Bragg peak widening filter 17 pass through the ridge filter 26, the Bragg peak is widened to have an SOBP (Spread-Out Bragg Peak) having a predetermined width. . That is, the irradiation field is expanded in the beam axis direction (depth direction) by the Bragg peak expansion filter 17 and the ridge filter 26.

  The operation of the particle beam irradiation apparatus 50 will be described. First, the energy of the particle beam 10 is set to the energy value planned in the treatment plan as the parameter of the particle beam generating and transporting apparatus 1. Thereafter, the particle beam 10 is generated and irradiation is started, and at the same time, dose measurement of the particle beam 10 by the dose monitor 5 is started. Irradiation of the particle beam 10 is continued until the measured dose value, which is the measured dose of the particle beam 10, reaches the planned dose value stored in the storage unit 3. When the measured dose value reaches the planned dose value stored in the storage unit 3, the irradiation of the particle beam 10 is terminated.

  When changing the energy of the particle beam 10, if the type of the accelerator of the particle beam generator / transporter 1 is a synchrotron, it is possible to change the energy of the particle beam by changing the operation pattern of the synchrotron It is. In addition, when the type of accelerator is a cyclotron, the energy of the particle beam 10 can be changed by arranging an energy selection system (ESS) in the middle of the particle beam transport path.

  The Bragg peak expansion filter 17 will be described in detail. As schematically shown in FIG. 2, the Bragg peak expansion filter 17 has a plane perpendicular to the traveling direction of the particle beam 10, that is, the beam axis direction, and is parallel to the first material portion 18 and the beam axis direction of the particle beam 10. It is formed from a plurality of holes 19 penetrating in any direction. In other words, it can be said that the Bragg peak expansion filter 17 is a plate in which a plurality of small through holes are formed. Further, the thickness of the first material portion 18 is smaller than the thickness capable of completely stopping the particle beam 10. For example, the thickness of the first material portion 18 is 0.5 mm when the material is aluminum, and 1 mm when the material is acrylic resin. FIG. 3 shows a view of the Bragg peak widening filter 17 viewed from the upstream side of the beam axis of the particle beam 10. The shape of the hole 19 is, for example, a circle, and the arrangement of the hole 19 is, for example, a square lattice. The distance (center distance) L between the center of the hole 19 and the center of the adjacent hole 19 is, for example, 2 mm. Further, the diameter D of the hole 19 is, for example, 1.5 mm. Such a structure can be manufactured by NC (Numerical Control) processing. Alternatively, it can be manufactured by photolithography.

  The Bragg peak widening filter 17 reduces the energy of a part of the particle beam 10 that passes therethrough. That is, the energy of the particle beam 10 that has passed through the first material portion 18 of the Bragg peak expanding filter 17 is reduced, and the energy of the particle beam 10 that has passed through the hole 19 is not reduced. As shown in FIG. 4, the particle beam 10 that has passed through the Bragg peak expansion filter 17 is divided into two particle beam components having different energies, and the width of the Bragg peak is increased by superimposing the two particle beam components. As described above, the Bragg peak expansion filter 17 has a function of increasing the width of the Bragg peak in the depth direction from the body surface of the patient 13. In FIG. 4, the horizontal axis represents the energy of the particle beam, and the vertical axis represents the frequency of each energy component of the particle beam. The energy component 30a having the energy E1 shown in FIG. 4 is an energy component due to the particle beam component that has passed through the first material portion 18, and the energy component 30b having the energy E2 is the energy component due to the particle beam component having passed through the hole portion 19. It is.

The shape of the Bragg peak whose width is increased by passing through the Bragg peak widening filter 17 is determined by the ratio of the two particle beam components. The ratio of the two particle beam components is the ratio of the area of the first material portion 18 and the hole portion 19 in the range through which the particle beam 10 of the Bragg peak expanding filter 17 passes, that is, viewed from the upstream side of the beam axis of the particle beam 10. Determined by area ratio. For example, the arrangement of the holes 19 as shown in FIG. 3 is a square lattice arrangement. If the hole 19 is a circle having a diameter D and the center of the hole 19 is located at the apex of a square having a side length L (square lattice-like arrangement), The area ratio Ra between the material portion 18 and the hole portion 19 can be calculated as shown in Expression (1).
^{L 2 -π × D 2/4} : π × D 2/4 ··· (1)

For example, when L = 2 mm and D = 1.5 mm, the area ratio Ra is approximately 5: 4. By changing the size and arrangement of the holes 19, the area ratio Ra can be freely adjusted to some extent. When the area of the hole portion 19 is too small with respect to the area of the first material portion 18, the lower energy component of the two particle beam components is dominant, and the Bragg peak shape is also almost low in energy. It depends on the component. In this case, the effect of expanding the Bragg peak width is not so much obtained. Specifically, the area of the hole portion 19 is desirably at least 1/10 or more of the area of the first material portion 18. The conditions necessary for this can be expressed as equation (2) using equation (1).
D / L> 0.34 (2)

  The operation of the Bragg peak expansion filter 17 will be described in comparison with a comparative example. FIG. 5 is a diagram showing the energy component of the particle beam after passing through the ridge filter of the first comparative example, and FIG. 6 is a diagram showing the dose distribution of the first comparative example. FIG. 7 is a diagram showing the dose distribution of the second comparative example. 8 is a diagram showing an example of the energy frequency distribution of the particle beam by the particle beam irradiation apparatus of FIG. 1, and FIG. 9 is a diagram showing the dose distribution corresponding to the energy frequency distribution of the particle beam of FIG. 5 and 8, the horizontal axis represents the energy of the particle beam, and the vertical axis represents the frequency of each energy component of the particle beam. 6, 7, and 9, the horizontal axis is the depth, that is, the position in the Z direction (Z position) inside the irradiation object 11, and the vertical axis is the particle beam dose.

  A 1st comparative example is an example which expands a Bragg peak with the particle beam irradiation apparatus in which the Bragg peak expansion filter 17 is not arrange | positioned. In the conventional particle beam irradiation apparatus in which the Bragg peak expanding filter 17 is not disposed, for example, 20 steps are formed on one surface of each wedge-shaped element of the ridge filter 26. In this case, the particle beam that has passed through the ridge filter 26 includes 20 or more particle beam components having different energies. The distribution of the number of charged particles with respect to energy is determined by the proportion of each step that determines the energy of the charged particles in one wedge-shaped element. For this reason, the energy distribution of the particle beam that has passed through the ridge filter 26 is determined by the shape of the longitudinal section of the wedge-shaped element. In the conventional irradiation field forming apparatus in which the Bragg peak expanding filter 17 is not installed, the distribution of energy components in the particle beam component of the particle beam that has passed through the ridge filter 26 having a wedge-shaped element having seven steps formed on one surface is shown in FIG. This is shown in FIG.

  The depth that the particle beam reaches in the body is determined by the energy that the particle beam has. A particle beam with high energy reaches a deep position, and a particle beam with low energy reaches a shallow position. In the case of a particle beam including seven particle beam components having different energies as shown in FIG. 5, when the particle beam is irradiated to the patient 13, each of the seven different particle beam components that reach the inside of the body according to the energy. A Bragg peak is formed at the position. The total dose distribution 32 in the body when irradiated with such a particle beam is obtained by adding the Bragg peaks in the depth direction of the body. FIG. 6 shows seven dose distributions 31a, 31b, 31c, 31d, 31e, 31f, and 31g having different Bragg peaks. In the total dose distribution 32 in which the seven dose distributions 31a, 31b, 31c, 31d, 31e, 31f, and 31g are added, the range in which the dose is high and uniform spreads in the depth direction.

  Consider a case in which the number of step portions formed on the wedge-shaped element of the ridge filter 26 is reduced and the step portion in the height direction is roughly formed. In the second comparative example, the Bragg peak expansion filter 17 is not disposed, and the Bragg peak is expanded by the particle beam irradiation apparatus having the ridge filter 26 having a smaller number of steps than the ridge filter 26 of the first comparative example. It is an example. When the number of step portions formed on the wedge-shaped element of the ridge filter 26 is reduced to make the gap between the step portions in the height direction rough, the ridge filter is easier to manufacture than the ridge filter 26 of the first comparative example. become. However, the number of particle beam components having different energies contained in the particle beam that has passed through the ridge filter 26 of the second comparative example is reduced, and the difference in energy between the particle beam components is increased. For this reason, as shown in FIG. 7, the total dose distribution 32 in the depth direction inside the irradiation object 11 has an uneven and uneven shape. In FIG. 7, four dose distributions 31a, 31c, 31e, and 31g having different Bragg peaks are shown. 7 shows an example in which the three dose distributions 31b, 31d, and 31f in FIG. 6 are removed.

  Next, the total dose distribution in the body when the Bragg peak widening filter 17 is installed on the upstream side of the ridge filter 26 will be described. The particle beam that has passed through the Bragg peak expansion filter 17 includes two particle beam components having different energies, as described above. In FIG. 8, the four energies of E1, E2, E3, and E4 passing through the hole 19 of the Bragg peak expanding filter 17 and the four steps of the wedge-shaped element of the ridge filter 26 are represented by the Bragg peak. The four energies that passed through the first material portion 18 of the magnifying filter 17 and passed through the four steps of the wedge-shaped element of the ridge filter 26 showed the energy components E1a, E2a, E3a, and E4a. FIG. 9 shows a total dose distribution 34 that combines the four dose distributions 33a, 33b, 33c, and 33d and the dose distributions 33a, 33b, 33c, and 33d. The dose distribution 33a is a dose distribution based on energy components of the energy E1a and E1. Similarly, the dose distribution 33b is a dose distribution based on the energy components of the energy E2a and E2, the dose distribution 33c is a dose distribution based on the energy components of the energy E3a and E3, and the dose distribution 33d is a dose based on the energy components of the energy E4a and E4. Distribution.

  By irradiating the particle beam that has passed through the ridge filter 26 located downstream of the Bragg peak expanding filter 17, the width of each Bragg peak formed in the body is widened as shown in FIG. Compared with the conventional particle beam irradiation apparatus in which the Bragg peak widening filter 17 is not installed, the particle beam irradiation apparatus 50 of the first embodiment is a total even if the number of steps of the ridge filter 26 and the processing accuracy are the same. It becomes easy to make the dose distribution uniform. Therefore, since the particle beam irradiation apparatus 50 according to the first embodiment includes the Bragg peak expansion filter 17 that decomposes the particle beam 10 into a plurality of particle beam components having different energies, the particle beam irradiation device 50 is formed in the body even when the Bragg peak is extremely thin and sharp. Each Bragg peak width can be smoothly expanded, and a uniform total dose distribution can be easily formed.

  In addition, the particle beam irradiation apparatus 50 according to the first embodiment reduces the number of steps of the ridge filter 26 while maintaining the uniformity of the total dose distribution, or relaxes the required processing accuracy. Manufacturing time can be shortened. Therefore, since the particle beam irradiation apparatus 50 according to the first embodiment includes the Bragg peak expansion filter 17 that decomposes the particle beam 10 into a plurality of particle beam components having different energies, the ridge filter 26 having a small number of steps is used. However, each Bragg peak width formed in the body can be smoothly expanded, and a uniform total dose distribution can be easily formed.

  Although FIG. 1 shows an example in which the Bragg peak widening filter 17 is arranged on the upstream side of the ridge filter 26, the Bragg peak widening filter 17 may be arranged on the downstream side of the ridge filter 26.

The Bragg peak expansion filter 17 is not limited to the configuration of the first example illustrated in FIGS. 2 and 3, and may have other configurations. As shown in FIG. 10, the arrangement of the holes 19 of the Bragg peak expansion filter 17 may be a hexagonal lattice arrangement. FIG. 10 is a front view showing a second example of the Bragg peak widening filter according to the first embodiment. In this case, the area ratio Ra between the first material portion 18 and the hole portion 19 can be calculated as in Expression (3).
^{L 2 × √3 / 2-π} × D 2/4: π × D 2/4 ··· (3)

In the hexagonal lattice arrangement, the area ratio Ra can be freely adjusted to some extent by changing the size and arrangement of the holes 19 in the same manner as the tetragonal lattice arrangement. As in the case of the square lattice arrangement, when the area of the hole 19 is too small with respect to the area of the first material portion 18, the effect of expanding the Bragg peak width is not obtained so much. The area of the hole 19 is preferably at least 1/10 of the area of the first material part 18. The condition necessary for this can be expressed as equation (4) using equation (3).
D / L> 0.316 (4)

  Further, the holes 19 may be arranged in a ring shape as shown in FIG. 11 or in a random arrangement as shown in FIG. FIG. 11 is a front view showing a third example of the Bragg peak widening filter according to the first embodiment, and FIG. 12 is a front view showing a fourth example of the Bragg peak widening filter according to the first embodiment.

  The shape of the hole 19 is not necessarily a circle, and may be a polygon as shown in FIG. 13, for example. Further, the sizes of the holes 19 are not necessarily equal to each other. For example, as shown in FIG. 14, a plurality of types of holes having different sizes may be used. In any example, the ratio of the particle beam component having two energies of the particle beam 10 that has passed through the Bragg peak expansion filter 17 is the same as that of the first material portion 18 in the range in which the particle beam 10 passes through the Bragg peak expansion filter 17. It is determined by the ratio of the area of the hole 19 viewed from the upstream side of the beam axis of the particle beam 10. FIG. 13 is a front view showing a fifth example of the Bragg peak widening filter according to the first embodiment, and FIG. 14 is a front view showing a sixth example of the Bragg peak widening filter according to the first embodiment.

  In the above description, the Bragg peak widening filter 17 of the first to sixth examples is described in the assumption that air is present in the hole 19 and air is present in the hole 19. However, due to the design of the irradiation system 6, the Bragg peak widening filter 17 may be disposed in a vacuum, and in that case, the element filling the hole 19 is a vacuum. Similarly, the Bragg peak widening filter 17 may be disposed in a gas chamber filled with helium gas. In this case, the element filling the hole 19 is helium.

  Still another Bragg peak widening filter 17 may be used. 15 is a front view showing a seventh example of the Bragg peak widening filter according to the first embodiment, and FIG. 16 is a front view showing an eighth example of the Bragg peak widening filter according to the first embodiment. As shown in FIG. 15, the hole portion 19 of the first material portion 18 may be disposed so as to be filled with a solid made of a material different from that of the first material portion 18. That is, the Bragg peak widening filter 17 of the seventh example is formed of a first material portion 18 and a second material portion 52 made of a material different from the first material portion 18. When the hole 19 of the first material part 18 is completely filled with solid, the name of the hole 19 is not appropriate, and the second material part 52 is used.

  By using materials having different stopping powers, that is, reducing powers for the particle beam 10 in the first material portion 18 and the second material portion 52, the particle beam 10 and the second material portion 52 that have passed through the first material portion 18 are used. Since the particle beam 10 that has passed through is subjected to energy reduction different from that of the particle beam 10, the same effect as in the case where the second material portion 52 is hollow can be obtained. The same effect can be obtained by using the same material for the first material portion 18 and the second material portion 52 and changing the thickness. As shown in FIG. 16, even if the first material portion 18 cannot be manufactured in an integral structure, the Bragg peak expanding filter 17 is integrated by filling the second material portion 52 with a solid. It can be formed as a structure.

  The size of the hole 19 of the Bragg peak expanding filter 17 is not constant with respect to the beam axis direction, and the hole 19 may be tapered as shown in FIG. FIG. 17 is a front view illustrating a ninth example of the Bragg peak widening filter according to the first embodiment. 18 is a cross-sectional view taken along the line AA in FIG. 17, and FIG. 19 is a diagram for explaining the energy component of the particle beam after passing through the Bragg peak expansion filter of FIG. FIG. 18 shows a cross-sectional view of the Bragg peak widening filter 17 cut along a plane including the broken line and the beam axis direction indicated by AA in FIG. The hole 19 has a wide opening on the upstream side in the direction in which the particle beam 10 travels (beam axis direction) and a narrow opening on the downstream side. The hole 19 has an upstream opening 59, a tapered portion 57 that is a tapered side surface, and a downstream opening 58. When the particle beam 10 passes through the Bragg peak widening filter 17 from a direction parallel to the beam axis 9, the particle beam 10 c passing through the downstream opening 58 is not subjected to energy reduction by the tapered portion 57. The downstream opening 58 can also be referred to as a bottom portion penetrating the first material portion 18. In FIG. 18, the locus of the particle beam 10 is schematically shown as three particle beams 10a, 10b, and 10c. The particle beam 10a that has passed through the first material portion 18 reduces energy and has a relatively low energy, and the particle beam 10c that has passed through the downstream opening 58 of the hole portion 19 does not reduce energy and has a relatively high energy. Have. Furthermore, the particle beam 10b that has passed through the tapered portion 57 formed in the tapered shape of the hole portion 19 has intermediate energy.

  Therefore, the particle beam 10 that has passed through the Bragg peak widening filter 17 of the ninth example is composed of particle beam components having a plurality of energies as shown in FIG. Compared to the case where there are two particle beam components having different energy of the particle beam 10 as shown in FIG. 4, the Bragg peak expanding filter 17 of the ninth example uses the particle beam 10 as three or more particles having different energy. The Bragg peak can be expanded in the irradiation target 11 by decomposing into a line component and using the plurality of decomposed particle beam components. FIG. 19 shows an example of nine energy components by particle beam components corresponding to nine different energies E1, E2, E3, E4, E5, E6, E7, E8, and E9. In FIG. 19, the horizontal axis represents the energy of the particle beam, and the vertical axis represents the frequency of each energy component of the particle beam. In the particle beam irradiation apparatus 50 provided with the Bragg peak expansion filter 17 of the ninth example, the dose distribution formed by three or more particle beam components is smoother than the dose distribution formed by two particle beam components. The curve shape of the dose distribution having the Bragg peak whose width has been expanded also becomes smooth, and the addition of a plurality of dose distributions having different Bragg peak positions makes it easier to form a uniform total dose distribution.

  The tapered hole portion 19 can also be expressed as the opening area on the upstream side of the beam axis 9 and the opening area on the downstream side of the beam axis 9 are different. The examples shown in FIGS. 17 and 18 are examples in which the upstream opening area is larger than the downstream opening area. The tapered hole portion 19 may have a case where the upstream opening area is smaller than the downstream opening area. Also in this case, since the energy of the particle beam 10 that has passed through the tapered portion 57 is reduced in accordance with the thickness of the tapered portion 57 that has passed through, the same effect as the example shown in FIGS. 17 and 18 can be obtained.

  The Bragg peak expansion filter 17 may be configured by a plurality of filter elements. FIG. 20 is a front view showing a tenth example of the Bragg peak widening filter according to the first embodiment. 21, 22 and 23 are front views showing the first filter element, the second filter element and the third filter element of FIG. 20, respectively. FIG. 24 is a front view of the hole portion seen from the upstream side of the beam axis in the Bragg peak expansion filter of FIG. 20, and FIG. 25 is a diagram for explaining the energy component of the particle beam after passing through the Bragg peak expansion filter of FIG. It is. In FIG. 25, the horizontal axis represents the energy of the particle beam, and the vertical axis represents the frequency of each energy component of the particle beam. In FIG. 20, the example of the Bragg peak expansion filter 17 comprised by the three filter elements 53a, 53b, and 53c was shown. Each filter element 53 a, 53 b, 53 c has a hole 19 having a size different from that of the first material portion 18. The filter elements 53 a, 53 b, and 53 c are formed from the first material portion 18 and a plurality of holes 19 that penetrate in the direction parallel to the beam axis direction of the particle beam 10, similarly to the Bragg peak expansion filter 17 of the first example. Is done. FIG. 21 is a view of one of the holes 19 as viewed from the upstream side of the beam axis when three filter elements 53a, 53b, and 53c are stacked. The openings 54a, 54b, and 54c are openings of the hole portions 19 of the filter elements 53a, 53b, and 53c, respectively.

  The energy component of the particle beam 10 that has passed through the Bragg peak expansion filter 17 of the tenth example is the first material portion 18 of the three filter elements 53a, 53b, and 53c and the openings 54a, 54b, and 54c of the hole portion 19. Four regions 55a, 55b, 55c, and 55d are formed by the combination. The region 55a is a region where the particle beam 10 passes through the first material portion 18 of the three filter elements 53a, 53b, and 53c. The region 55b is a region through which the particle beam 10 passes through the two first material portions 18 and the one hole portion 19 in the three filter elements 53a, 53b, and 53c. In FIG. 24, the area | region 55b showed the example of the area | region through which the particle beam 10 passes through the two 1st material parts 18 in the two filter elements 53b and 53c, and the opening 54a of the hole 19 of the filter element 53a. The region 55c is a region through which the particle beam 10 passes through the first material portion 18 and the two holes 19 in the three filter elements 53a, 53b, and 53c. In FIG. 24, the area | region 55c showed the example of the area | region through which the particle beam 10 passes the 1st material part 18 in the filter element 53c of 1 sheet, and opening 54a, 54b of the hole 19 of filter element 53a, 53b. The region 55d is a region through which the particle beam 10 passes through the openings 54a, 54b, 54c of the hole 19 of the three filter elements 53a, 53b, 53c.

  The particle beam 10 that has passed through the Bragg peak expansion filter 17 of the tenth example is decomposed into particle beam components having four different energies E1, E2, E3, and E4 corresponding to the regions 55a, 55b, 55c, and 55d that have passed therethrough. Is done. The frequency distribution of the energy component of the particle beam 10 that has passed through the Bragg peak expansion filter 17 of the tenth example is as shown in FIG. 25, for example. Even in the configuration of the Bragg peak widening filter 17 of the tenth example, the width is approximately expanded in the same manner as the Bragg peak widening filter 17 of the ninth example having the tapered hole portion 19 shown in FIG. The effect of smoothing the curve shape of the dose distribution having the Bragg peak can be obtained.

  By increasing the number of filter elements, the Bragg peak expansion filter 17 of the tenth example can obtain an effect of further smoothing the curve shape of the dose distribution having the Bragg peak whose width is expanded. When the number of filter elements is two, the region passing through the two first material portions 18, the region passing through the one first material portion 18 and the one hole portion 19, and the region passing through the two hole portions 19 Is formed. The Bragg peak widening filter 17 of the tenth example including two filter elements can decompose the particle beam 10 into particle beam components having three different energies E1, E2, and E3. Therefore, since the particle beam irradiation apparatus 50 including the Bragg peak widening filter 17 of the tenth example having a plurality of filter elements can form a dose distribution by three or more particle beam components, the Bragg peak widening filter of the first example 17 is smoother than the dose distribution formed by the two particle beam components, the curve shape of the dose distribution having a Bragg peak with an expanded width is also smooth. And the particle beam irradiation apparatus 50 provided with the Bragg peak expansion filter 17 of the tenth example having a plurality of filter elements can form a uniform total dose distribution by adding a plurality of dose distributions having different Bragg peak positions. It becomes easier. The particle beam irradiation apparatus 50 including the Bragg peak widening filter 17 of the tenth example having the three filter elements 53a, 53b, and 53c shown in FIG. 20 can form a dose distribution with four particle beam components.

  Another example of the Bragg peak widening filter 17 composed of a plurality of filter elements will be described with reference to FIGS. FIG. 26 is a front view showing an eleventh example of the Bragg peak widening filter according to the first embodiment. 27, 28, 29, and 30 are front views showing the first filter element, the second filter element, the third filter element, and the fourth filter element of FIG. 26, respectively. FIG. 31 is a front view of the hole viewed from the upstream side of the beam axis in the Bragg peak widening filter of FIG. In FIG. 26, four filter elements 53a, 53b, 53c, and 53d are configured, and the size of the hole 19 of each filter element 53a, 53b, 53c, and 53d is the same, and the arrangement of the holes 19 is different. An example of the Bragg peak expansion filter 17 is shown. The filter elements 53 a, 53 b, 53 c, and 53 d include the first material portion 18 and a plurality of hole portions 19 penetrating in a direction parallel to the beam axis direction of the particle beam 10, similarly to the Bragg peak expansion filter 17 of the first example. Formed from. FIG. 31 is a view of one of the holes 19 as viewed from the upstream side of the beam axis when the four filter elements 53a, 53b, 53c, and 53d are overlapped. The openings 54a, 54b, 54c, and 54d are openings of the hole portions 19 of the filter elements 53a, 53b, 53c, and 54d, respectively.

  The energy component of the particle beam 10 that has passed through the Bragg peak widening filter 17 of the eleventh example includes the first material portion 18 of the four filter elements 53a, 53b, 53c, and 53d, and the openings 54a, 54b of the hole portion 19, Five regions 56a, 56b, 56c, 56d, and 56e are formed by the combination of 54c and 54d. The region 56a is a region where the particle beam 10 passes through the first material portions 18 of the four filter elements 53a, 53b, 53c, and 53d. The region 56b is a region through which the particle beam 10 passes through the three first material portions 18 and the one hole portion 19 in the four filter elements 53a, 53b, 53c, and 53d. The region 56c is a region where the particle beam 10 passes through the two first material portions 18 and the two hole portions 19 in the four filter elements 53a, 53b, 53c, and 53d. The region 56d is a region through which the particle beam 10 passes through one first material portion 18 and three hole portions 19 in the four filter elements 53a, 53b, 53c, and 53d. The region 56e is a region through which the particle beam 10 passes through the holes 19 of the four filter elements 53a, 53b, 53c, and 53d.

  The regions 56b, 56c, 56d, and 56e will be described by taking the inside of the opening 54a of the filter element 53a on the most upstream side as viewed from the upstream side of the beam axis 9 indicated by a solid circle in FIG. 31 as an example. The region 56b is a region through which the particle beam 10 passes through the opening 54a of the filter element 53a and the three first material portions 18 in the three filter elements 53b, 53c, and 53d. There are two regions 56c. The first region 56c is a region through which the particle beam 10 passes through the two openings 54a and 54b of the two filter elements 53a and 53b and the two first material portions 18 of the two filter elements 53c and 53d. . The second region 56c is a region through which the particle beam 10 passes through the two openings 54a and 54d of the two filter elements 53a and 53d and the two first material portions 18 of the two filter elements 53b and 53c. . There are two regions 56d. The first region 56d is a region through which the particle beam 10 passes through the three openings 54a, 54b, 54c of the three filter elements 53a, 53b, 53c and one first material portion 18 of the filter element 53d. The second region 56d is a region that passes through the three openings 54a, 54c, 54d of the three filter elements 53a, 53c, 53d and one first material portion 18 of the filter element 53b. The region 56e is a region through which the particle beam 10 passes through the four openings 54a, 54b, 54c, 54d of the four filter elements 53a, 53b, 53c, 53d.

  The particle beam 10 that has passed through the Bragg peak widening filter 17 of the eleventh example has particles having five different energies E1, E2, E3, E4, and E5 corresponding to the regions 56a, 56b, 56c, 56d, and 56e that have passed therethrough. Decomposed into line components. Even in the configuration like the Bragg peak widening filter 17 of the eleventh example, the width is expanded in the same manner as the Bragg peak widening filter 17 of the ninth example having the tapered hole portion 19 shown in FIG. The effect of smoothing the curve shape of the dose distribution having the Bragg peak can be obtained.

  By increasing the number of filter elements, the Bragg peak expansion filter 17 of the eleventh example can obtain an effect of further smoothing the curve shape of the dose distribution having the Bragg peak whose width is expanded. When the number of filter elements is two, the region passing through the two first material portions 18, the region passing through the one first material portion 18 and the one hole portion 19, and the region passing through the two hole portions 19 Is formed. The eleventh example Bragg peak widening filter 17 having two filter elements can decompose the particle beam 10 into particle beam components having three different energies E1, E2, and E3. Therefore, the particle beam irradiation apparatus 50 including the eleventh example Bragg peak widening filter 17 having a plurality of filter elements can form a dose distribution with three or more particle beam components, so the Bragg peak widening filter of the first example. 17 is smoother than the dose distribution formed by the two particle beam components, the curve shape of the dose distribution having a Bragg peak with an expanded width is also smooth. And the particle beam irradiation apparatus 50 provided with the Bragg peak expansion filter 17 of the eleventh example having a plurality of filter elements can form a uniform total dose distribution by adding a plurality of dose distributions having different Bragg peak positions. It becomes easier. The particle beam irradiation apparatus 50 including the eleventh example of the Bragg peak widening filter 17 having four filter elements 53a, 53b, 53c, and 53d shown in FIG. 26 can form a dose distribution with five particle beam components.

  The Bragg peak widening filter 17 may be a porous three-dimensional structure having a plurality of hollow portions three-dimensionally. FIG. 32 is a front view showing a twelfth example of the Bragg peak widening filter according to the first embodiment. FIG. 32 shows an example in which spherical hole portions 19 are formed at a plurality of locations in the first material portion 18 that is a block having an acrylic rectangular parallelepiped shape. In the particle beam 10 that has passed through the Bragg peak widening filter 17 of the twelfth example, if there is also a component that has undergone a relatively large energy reduction without passing through the hole 19, it is relatively Some components have undergone a small energy reduction. Further, since the size and the number of the holes 19 passing therethrough vary depending on the passage position of the particle beam 10, the frequency distribution of the energy component of the particle beam 10 that has passed through the Bragg peak expansion filter 17 of the twelfth example is continuous. With a wide width. For this reason, the Bragg peak widening filter 17 of the twelfth example has the effect of smoothing the curve shape of the dose distribution having the Bragg peak whose width is widened, like the Bragg peak widening filter 17 of the tenth and eleventh examples. can get. The Bragg peak widening filter 17 of the twelfth example having a porous three-dimensional structure as shown in FIG. 32 can be manufactured by, for example, a laminated molding (3D printer).

  In the Bragg peak widening filter 17 of the first to sixth examples and the ninth example, the example in which the hole 19 is penetrated is shown, but the hole 19 is recessed in a direction parallel to the beam axis 9 even if it is not penetrated. It may be a hole. 47, which will be described later, may have a bottom portion 60 that does not penetrate the downstream side of the beam axis 9, and the upstream side of the beam axis 9 may not penetrate and the downstream side may be recessed. Further, a thin portion may be provided in the middle of the hole 19 in the direction parallel to the beam axis 9, and the upstream side and the downstream side of the beam axis 9 may be recessed. Further, in the Bragg peak widening filter 17 of the tenth example and the eleventh example, the example in which the hole 19 of each filter element penetrates is shown, but even if it is not penetrated, it is recessed in the direction parallel to the beam axis 9. It may be a hole.

  As described above, the particle beam irradiation apparatus 50 according to the first embodiment includes the particle beam generating / transporting apparatus 1 that generates and transports the accelerated particle beam 10, and the particle beam 10 transported from the particle beam generating / transporting apparatus 1. And an irradiation system 6 that irradiates the irradiation object 11 with the irradiation system 11. The irradiation system 6 decomposes the particle beam 10 into a plurality of particle beam components having different energies, and the scanning device 2 that deflects the particle beam 10 in two directions perpendicular to the beam axis 9 of the transported particle beam 10. A Bragg peak expansion filter 17 that expands the width in the depth direction of the Bragg peak in the irradiation object 11 by the decomposed particle beam component. A plurality of Bragg peak expansion filters 17 are arranged on the surfaces of the first material portion 18 having a thickness in the direction parallel to the beam axis 9 and the first material portion 18 perpendicular to the beam axis 9, and the direction parallel to the beam axis 9. And a hole 19 that is recessed in a direction parallel to the beam axis 9. The particle beam irradiation apparatus 50 according to the first embodiment includes the Bragg peak expansion filter 17 in which a plurality of hole portions 19 penetrating or recessed in the surface of the first material portion 18 are provided. Even when it is extremely thin and sharp, the Bragg peak width can be expanded smoothly, and a uniform total dose distribution can be easily formed.

Embodiment 2. FIG.
The Bragg peak expansion filter 17 shown in the first embodiment can also be used in scanning irradiation (spot scanning irradiation, raster scanning irradiation, etc.) by a scanning irradiation method. FIG. 33 is a schematic configuration diagram of the particle beam irradiation apparatus according to the second embodiment. The particle beam irradiation apparatus 50 according to the second embodiment is an example that performs scanning irradiation by a scanning irradiation method. A particle beam irradiation apparatus 50 according to the second embodiment accelerates charged particles to necessary energy, generates accelerated charged particles as particle beams 10, and transports them to the scanning apparatus 2. Two directions perpendicular to the Z direction, that is, the beam traveling direction (beam axis direction) in which the particle beam travels from the upstream side to the downstream side of the particle beam 10 generated by the particle beam generating and transporting apparatus 1, that is, the X and Y directions. And a scanning device 2 that scans an arbitrary position of the irradiation object 11 (irradiation position planned in the treatment plan) within the patient tumor. Usually, the particle beam generating and transporting apparatus 1 includes an accelerator for accelerating charged particles and a transport system for transporting the particle beam 10 from the accelerator to the scanning device 2. The scanning device 2 includes an X-direction scanning device 21 that deflects the particle beam 10 in the X direction and a Y-direction scanning device 22 that deflects the particle beam 10 in the Y direction.

  The particle beam generating and transporting apparatus 1 can change the energy of the particle beam 10 to be generated. For example, when the particle beam generating and transporting apparatus 1 is a synchrotron, it is possible to generate particle beams having different energies by changing the operation parameters of the synchrotron. For example, when the particle beam generating / transporting apparatus 1 is a cyclotron, it is possible to generate particle beams having different energies by arranging an energy selection system (ESS) on the particle beam transport path. .

  Further, the particle beam irradiation apparatus 50 stores the position information of each irradiation position 12 in the irradiation target 11, the scheduled dose value of the particle beam 10 to be irradiated to each irradiation position 12, the scanning speed information of the scanning apparatus 2, and the like. 3, the control unit 4 that controls the start and block of the emission of the particle beam 10 by the particle beam generation and transport device 1 and the scanning of the particle beam 10 by the scanning device 2, and the irradiation of the particle beam 10 scanned by the scanning device 2 The dose monitor 5 which measures the dose value irradiated to each irradiation position 12 of the object 11 is provided. In addition, as position information of each irradiation position 12 memorize | stored in the memory | storage part 3, as irradiation position number, the positional information in the XY coordinate system of each irradiation position 12, and the particle beam 10 are X position and Y position of each irradiation position 12, for example. There are excitation current values of the X-direction scanning device 21 and the Y-direction scanning device 22 which are scanning electromagnets of the scanning device 2 for deflecting the light to each other, and energy corresponding to the Z position (position in the Z direction) of each irradiation position 12. .

  Further, the particle beam irradiation apparatus 50 includes a Bragg peak widening filter 17 at least at a part on a path through which the particle beam 10 is scanned and passed. The Bragg peak expansion filter 17 has, for example, a plane perpendicular to the direction of the beam axis 9 of the particle beam 10, that is, an XY plane perpendicular to the Z direction, as shown in FIG. It is formed from a plurality of holes 19 penetrating in a direction parallel to the direction of ten beam axes 9. The Bragg peak widening filter 17 is not limited to the Bragg peak widening filter of the first example shown in FIG. 2, but may be other configurations exemplified in the first embodiment or a combination thereof. The scanning device 2, the dose monitor 5, and the Bragg peak expansion filter 17 are an irradiation system 6 that irradiates the particle beam 10 with an irradiation field formed on the irradiation object 11.

  The scanning irradiation operation by the particle beam irradiation apparatus 50 according to the second embodiment will be described with reference to FIG. FIG. 34 is a flowchart showing the operation of the particle beam irradiation apparatus of FIG. In step F01, the irradiation operation is started. First, the parameter of the particle beam generator / transporter 1 is set so that the energy of the particle beam 10 becomes the first energy to be irradiated (step F02). The parameters of the scanning device 2 are set so that the irradiation position 12 of the particle beam 10 becomes the first irradiation position 12 corresponding to the first energy (step F03). Thereafter, the particle beam 10 is generated and irradiation is started, and at the same time, dose measurement of the particle beam 10 by the dose monitor 5 is started (step F04). In step F05, the irradiation of the particle beam 10 is continued until the measured dose value, which is the measured dose of the particle beam 10, reaches the planned dose value stored in the storage unit 3. When the measured dose value reaches the planned dose value stored in the storage unit 3, the process proceeds to Step F06.

  In step F06, it is determined whether or not the irradiation position 12 is the final irradiation position within the set energy. If it is determined that the irradiation position is not the final irradiation position, the process proceeds to step F08, and if it is determined that the irradiation position is the final irradiation position Advances to step F07. In step F08, the parameters of the scanning device 2 are set so that the irradiation position 12 of the particle beam 10 becomes the next irradiation position 12 stored in the storage unit 3, the irradiation to the next irradiation position 12 is continued, and the next Measurement for the irradiation position 12 is started. When the measured dose value for the next irradiation position 12 reaches the planned dose value stored in the storage unit 3 in step F05, the determination in step F06 is performed again.

  In step F06, it is determined whether or not the irradiation position 12 is the final irradiation position within the same energy. If it is determined that the irradiation position is the final irradiation position, irradiation of the particle beam 10 is stopped in step F07. Next, it is determined whether or not the energy is the planned final energy (step F09). If it is determined in step F09 that the energy is not the final energy, the energy of the particle beam 10 generated by the particle beam generator / transporter 1 is changed to the next energy (step F10), and the series from step F03 is performed again. Repeat the steps. If it is determined in step F09 that the energy is the final energy, the irradiation is terminated (step F11).

  Next, effects of the particle beam irradiation apparatus 50 that performs scanning irradiation according to the second embodiment will be described. FIG. 35 is a diagram showing an example of the energy frequency distribution of the particle beam by the particle beam irradiation apparatus of the comparative example, and FIG. 36 is a diagram showing the dose distribution corresponding to the energy frequency distribution of the particle beam of FIG. FIG. 37 is a diagram showing an example of the energy frequency distribution of the particle beam by the particle beam irradiation apparatus of FIG. 33, and FIG. 38 is a diagram showing the dose distribution corresponding to the energy frequency distribution of the particle beam of FIG. 35 and 37, the horizontal axis represents the energy of the particle beam, and the vertical axis represents the frequency of each energy component of the particle beam. 36 and 38, the horizontal axis represents the depth, that is, the position in the Z direction (Z position) inside the irradiation target, and the vertical axis represents the dose of the particle beam. FIG. 35 is an example of the energy frequency distribution of the particle beam irradiated by the particle beam irradiation apparatus when the Bragg peak expansion filter 17 is not used. FIG. 36 shows the relationship between the Z position and the dose inside the irradiation target, corresponding to the energy frequency distribution of FIG. In scanning irradiation, a three-dimensional dose distribution should be considered originally, but only one dimension in the Z direction will be described here for simplicity. In scanning irradiation, typically, energy is changed by about 10 to 30 steps. Here, for simplicity, only four steps of energy E1, E2, E3, and E4 are shown in the drawing. Dose distributions 31a, 31b, 31c, and 31d are dose distributions due to energy components of energy E1, E2, E3, and E4, respectively. The total dose distribution 32 is a total dose distribution obtained by combining the dose distributions 31a, 31b, 31c, and 31d.

  In general, in particle beam therapy, it is desirable that the dose inside the irradiation object 11 be uniform. However, since the dose distribution in the depth direction (Z direction) when the particle beam 10 having a single energy is irradiated has a steep Bragg peak, depending on the energy interval of the Bragg peak, particles of each energy It may be difficult to make the total dose distribution overlaid with the Bragg peaks formed by the line 10 uniform. The simplest means to solve this problem is to close the energy spacing of the Bragg peaks. However, if the energy intervals of the Bragg peaks are made close, the number of energy steps necessary to cover the entire area of the irradiation object 11 increases, and therefore the number of energy changes increases, and the total irradiation time becomes longer. is there. In addition, since the number of energy stages increases and the number of irradiation positions 12 also increases, the planned dose value for one irradiation position 12 becomes smaller on average, and there is a problem that precise control of the irradiation dose becomes difficult. .

  On the other hand, when the Bragg peak expansion filter 17 is used, as shown in FIGS. 37 and 38, the number of energy components of the particle beam 10 is doubled compared to the comparative example, and the total dose distribution is compared with the comparative example. It can be made uniform in comparison. FIG. 37 is an example of the frequency distribution of energy of the irradiated particle beam 10 when the Bragg peak widening filter 17 is used. FIG. 38 shows the relationship between the Z position and the dose in the irradiation object 11 corresponding to the energy frequency distribution of FIG. Here, as an example, a Bragg peak widening filter in which the area ratio of the first material portion 18 and the hole portion 19 is 1: 1 is assumed. The particle beam 10 passes through the Bragg peak widening filter 17, thereby passing through the first material portion 18, and the reduced particle beam component having reduced energy, that is, each particle beam component having energy Ea1, Ea2, Ea3, Ea4, and A non-reduced particle beam component that passes through the hole 19 and does not reduce energy, that is, each particle beam component having energy E1, E2, E3, E4, and is decomposed into two particle beam components having different energies To 11.

  When the energy change in four stages is performed by the particle beam generator / transporter 1, the particle beam 10 of each energy is divided into two particle beam components. For this reason, the particle beam 10 finally reaching the irradiation target 11 has a total of eight types of energy particle beam components. That is, as shown in FIG. 37, the particle beam 10 divided into particle beam components having energy Ea1, E1, Ea2, E2, Ea3, E3, Ea4, and E4 reaches the irradiation object 11. The sum of the dose distributions formed by the decomposed reduced particle beam component and the non-reduced particle beam component for the one-stage energy generated by the particle beam generating and transporting apparatus 1 is compared with the original Bragg peak. The peak width is expanded. The dose distribution 33a is a dose distribution based on particle beam components having energies Ea1 and E1. Similarly, the dose distribution 33b is a dose distribution based on particle beam components having the energy Ea2 and E2, the dose distribution 33c is a dose distribution based on particle beam components having the energy Ea3 and E3, and the dose distribution 33d includes the energy Ea4 and E4. It is a dose distribution by the particle beam component. The total dose distribution 34 is a total dose distribution obtained by combining the dose distributions 33a, 33b, 33c, and 33d. Therefore, the particle beam irradiation apparatus 50 according to the second embodiment can easily make the total dose distribution 34 obtained by combining the irradiation dose distributions of all the stages of energy.

Embodiment 3 FIG.
The Bragg peak widening filter 17 shown in the first embodiment can be used for scanning irradiation that is different from that in the second embodiment, that is, without energy change. FIG. 39 is a diagram for explaining a main part of the particle beam irradiation apparatus according to the third embodiment. The constituent elements of the particle beam irradiation apparatus 50 according to the third embodiment are the same as those of the particle beam irradiation apparatus 50 according to the second embodiment except for the shape of the Bragg peak expansion filter 17. For this reason, in FIG. 39, only the Bragg peak expansion filter 17, the particle beam 10, and the irradiation target 11a are illustrated, and the description of other components is omitted. The operation of the particle beam irradiation apparatus 50 of the third embodiment is the same as that of the particle beam irradiation apparatus 50 of the second embodiment except that the energy is not changed. Is the same as in the case of one stage and is omitted.

  The irradiation object 11a shown in FIG. 39 has a depth direction (Z direction) in the range 35a and a depth direction (Z direction) in the range 35b with respect to the direction of the beam axis 9 of the particle beam 10. This is an example that is larger than the thickness. The particle beam irradiation apparatus 50 of Embodiment 3 has the Bragg peak expansion filter 17, and the 1st material part 18 of the Bragg peak expansion filter 17 has different thickness based on the thickness of the irradiation object 11a. The range 35a is a range from the broken line 37a to the broken line 37b, and the range 35b is a range from the broken line 37b to the broken line 37c. The Bragg peak expanding filter 17 includes a filter unit 38a corresponding to the range 35a and a filter unit 38b corresponding to the range 35b. The thickness of the filter part 38a in the depth direction (Z direction) is larger than the thickness of the filter part 38b in the depth direction (Z direction). The Bragg peak widening filter 17 of Embodiment 3 has a plurality of regions (filter portions 38a and 38b) having different thicknesses in the direction parallel to the beam axis 9 of the first material portion 18, and each region (filter portion 38a). 38b), the thickness of the first material portion 18 is determined based on the thickness in the beam axis direction of the irradiation target 11 irradiated with the particle beam 10 through the first material portion 18. In FIG. 39, the body surface 36 is also shown.

  The Bragg peak expansion filter 17 according to the third embodiment will be described with reference to FIGS. 40 to 45. 40 is a cross-sectional view of the first filter portion of FIG. 41 is a diagram for explaining the energy component of the particle beam after passing through the first filter unit of FIG. 40, and FIG. 42 is a diagram showing an example of a dose distribution by the first filter unit of FIG. 43 is a cross-sectional view of the second filter portion of FIG. 44 is a diagram for explaining the energy component of the particle beam after passing through the second filter unit of FIG. 39, and FIG. 45 is a diagram showing an example of a dose distribution by the second filter unit of FIG. The Bragg peak widening filter 17 has a tapered hole portion 19 in the same manner as the Bragg peak widening filter 17 of the ninth example (see FIGS. 17 and 18). The hole 19 has a wide opening on the upstream side in the direction in which the particle beam 10 travels (beam axis direction) and a narrow opening on the downstream side. The hole 19 has an upstream opening 59, a tapered portion 57 that is a tapered side surface, and a downstream opening 58. That is, the Bragg peak expansion filter 17 has an upstream opening 59, a tapered portion 57 that is a tapered side surface, and a downstream opening 58 that is a bottom portion penetrating the first material portion 18. The Bragg peak expansion filter 17 includes a filter part 38a and a filter part 38b having first material parts 18 having different thicknesses. 40 shows a cross section of the filter section 38a, and FIG. 43 shows a cross section of the filter section 38b. 41 and 44, the horizontal axis represents the energy of the particle beam, and the vertical axis represents the frequency of each energy component of the particle beam. 42 and 45, the horizontal axis represents the depth, that is, the position in the Z direction (Z position) inside the irradiation target, and the vertical axis represents the dose of the particle beam.

  First, the filter unit 38a will be described. The particle beam 10a that has passed through the first material portion 18 has a relatively low energy with reduced energy. The particle beam 10c that has passed through the hole 19 has a relatively high energy without being reduced in energy. Further, the particle beam 10 b that has passed through the tapered portion 57 of the hole portion 19 has intermediate energy depending on the thickness of the tapered portion 57. Therefore, the particle beam 10 that has passed through the Bragg peak expansion filter 17 is composed of particle beam components having a plurality of energies as shown in FIG. At this time, by appropriately designing the thickness of the first material portion 18 and the shape of the tapered portion 57, the frequency distribution of the particle beam components having a plurality of energies is adjusted, and the total dose obtained by summing up the dose distributions of all the components. The distribution 39a can be made uniform within the irradiation target 11a in the range 35a as shown in FIG.

  The energy component 40 a is an energy component of the particle beam component in the particle beam 10 a having the energy Ea1 that has passed through the first material portion 18. The energy component 40g is an energy component of the particle beam component in the particle beam 10c having the energy Ea7 that has passed through the downstream opening 58 of the hole 19. The energy components 40b, 40c, 40d, 40e, and 40f are energy components of the particle beam component in the particle beam 10b having energy Ea2, Ea3, Ea4, Ea5, and Ea6 that have passed through the tapered portion 57 of the hole 19, respectively. For example, the energy component 40b is an energy component of the particle beam component in the particle beam 10b having energy Ea2 that has passed through the side farther from the body surface 36 in the tapered portion 57 of the hole portion 19, that is, the shallow side in the Z direction. The energy component 40f is an energy component of the particle beam component in the particle beam 10b having the energy Ea6 that has passed through the side closer to the body surface 36 in the tapered portion 57 of the hole portion 19, that is, the deep side in the Z direction.

  Next, the filter unit 38b will be described. Similar to the filter unit 38a in the range 35a, the particle beam 10 that has passed through the filter unit 38b of the Bragg peak expansion filter 17 is configured by particle beam components having a plurality of energies as shown by energy components 41a to 41g in FIG. The However, since the thickness of the first material part 18 of the filter part 38b is smaller than the first material part 18 of the filter part 38a, the particle beam component of the particle beam 10a that has passed through the first material part 18 of the filter part 38b is the filter part. Compared with the particle beam component of the particle beam 10a that has passed through the first material portion 18 of 38a, it has higher energy. Therefore, the separation between the maximum energy and the minimum energy in the particle beam component of the particle beam 10 that has passed through the filter unit 38b is compared with the separation between the maximum energy and the minimum energy in the particle beam component of the particle beam 10 that has passed through the filter unit 38a. Small.

  The energy component 41a is an energy component of the particle beam component in the particle beam 10a having the energy Eb1 that has passed through the first material portion 18. The energy component 41g is an energy component of the particle beam component in the particle beam 10c having the energy Eb7 that has passed through the downstream side opening 58 of the hole 19. The energy components 41b, 41c, 41d, 41e, and 41f are energy components of the particle beam component in the particle beam 10b having the energy Eb2, Eb3, Eb4, Eb5, and Eb6 that have passed through the tapered portion 57 of the hole 19, respectively. For example, the energy component 41b is an energy component of the particle beam component in the particle beam 10b having the energy Eb2 that has passed through the side farther from the body surface 36 in the tapered portion 57 of the hole portion 19, that is, the shallow side in the Z direction. The energy component 41f is an energy component of the particle beam component in the particle beam 10b having the energy Eb6 that has passed through the side closer to the body surface 36 in the tapered portion 57 of the hole portion 19, that is, the deep side in the Z direction. Note that the energy Ea7 of the energy component 40g of the particle beam component that has passed through the downstream opening 58 of the hole 19 of the filter portion 38a and the energy component of the particle beam component that has passed through the downstream opening 58 of the hole 19 of the filter portion 38b. The energy value is the same as the energy Eb7 of 41 g.

  In the filter part 38b as well as the filter part 38a, by appropriately designing the thickness of the first material part 18 and the shape of the tapered part 57, the frequency distribution of the particle beam component having a plurality of energies is adjusted, The total dose distribution 39b obtained by summing up the dose distributions of the components can be made uniform within the irradiation target 11a in the range 35b as shown in FIG. However, the width in the depth direction of the portion where the dose becomes uniform is smaller than that in the range 35a.

  At this time, in the range 35a, compared with the range 35b, it should be noted that the energy component distribution is expanded in a wider range in the depth direction, and the energy applied per unit volume in the irradiation target 11a is reduced. (Action 1). Therefore, even if the amount of the particle beam 10 emitted from the particle beam generator / transporter 1 is the same, the dose given to the irradiation object 11a is lower in the range 35a than in the range 35b. Therefore, in order to form a three-dimensional uniform dose distribution over the entire area of the irradiation target 11a, the irradiation position 12 within the range 35a is irradiated to the irradiation position 12 within the range 35b in consideration of the above-described action 1. It is necessary to set a planned dose value higher than that at position 12. As described above, by using the Bragg peak expanding filter 17 in which the thickness of the first material portion 18 varies depending on the irradiation position 12, the thickness of the first material portion 18 and the shape of the tapered portion 57 of the hole portion 19 are appropriately designed. It is possible to form a uniform dose distribution for the irradiation object 11a having different thicknesses in the depth direction (Z direction).

  In FIG. 39, an example in which the distance from the body surface 36 to the bottom surface of the irradiation target 11a (the far end as viewed from the upstream of the irradiation direction of the particle beam 10) is constant regardless of the irradiation position in the X direction and the Y direction. Indicated. Next, the Bragg peak expansion filter 17 corresponding to the irradiation target 11b having a different distance from the body surface 36 to the bottom surface will be described. FIG. 46 is a diagram for explaining a main part of another particle beam irradiation apparatus according to Embodiment 3, and FIG. 47 is a cross-sectional view of the third filter part of FIG. FIG. 48 is a diagram for explaining the energy component of the particle beam after passing through the third filter unit in FIG. 46, and FIG. 49 is a diagram showing an example of a dose distribution by the third filter unit in FIG. In FIG. 48, the horizontal axis represents the energy of the particle beam, and the vertical axis represents the frequency of each energy component of the particle beam. In FIG. 49, the horizontal axis represents the depth, that is, the position in the Z direction (Z position) inside the irradiation target, and the vertical axis represents the dose of the particle beam.

  In FIG. 46, the distance from the body surface 36 to the bottom surface of the irradiation target 11b is an example in which the range 35b is shorter than the range 35a. That is, in this example, the position of the bottom surface of the irradiation target 11b from the body surface 36 is closer to the range 35b than to the range 35a. The Bragg peak widening filter 17 shown in FIG. 46 includes a filter part 38a and a filter part 38c having first material parts 18 having different thicknesses as in FIG. The filter unit 38a is the same as that described with reference to FIG. The filter part 38c has the hole 19 which does not penetrate. The filter part 38c has a shape in which a structure without holes is further overlapped with the filter part 38b shown in FIG. The hole portion 19 of the filter portion 38c has an upstream opening 59, a tapered portion 57 that is a tapered side surface, and a bottom portion 60 that does not penetrate. By using the Bragg peak widening filter 17 having such a configuration, the maximum energy (see energy Ec7 in FIG. 48) of the particle beam component of the particle beam 10 that has passed through the range 35b in FIG. 46 is the range 35b in FIG. The energy is lower than the maximum energy (see energy Eb7 in FIG. 44) of the particle beam component of the particle beam 10 that has passed. Therefore, the deep end of the uniform region of the total dose distribution 39c formed in the range 35b of FIG. 46 is a shallower side than the deep end of the total dose distribution 39b formed in the range 35b of FIG. By doing so, it is possible to form a uniform dose distribution with respect to an irradiation target having a different distance from the body surface 36 to the bottom surface, like the irradiation target 11b of FIG.

  The particle beam 10 that has passed through the filter portion 38c of the Bragg peak expansion filter 17 has a plurality of energy components as shown by energy components 42a to 42g in FIG. 48, similarly to the filter portion 38b in the range 35b in FIG. Consists of. The energy component 42 a is an energy component of the particle beam component in the particle beam 10 a having the energy Ec1 that has passed through the first material portion 18. The energy component 42g is an energy component of the particle beam component in the particle beam 10c having the energy Ec7 that has passed through the bottom 60 of the hole 19. The energy components 42b, 42c, 42d, 42e, and 42f are the energy components of the particle beam component in the particle beam 10b having energy Ec2, Ec3, Ec4, Ec5, and Ec6 that have passed through the tapered portion 57 of the hole 19, respectively. For example, the energy component 42b is an energy component of the particle beam component in the particle beam 10b having the energy Ec2 that has passed through the side farther from the body surface 36 in the tapered portion 57 of the hole portion 19, that is, the shallow side in the Z direction. The energy component 42f is an energy component of the particle beam component in the particle beam 10b having the energy Ec6 that has passed through the side closer to the body surface 36 in the tapered portion 57 of the hole portion 19, that is, the deep side in the Z direction. In addition, when the thickness of the filter part 38b and the thickness of the filter part 38c are the same, energy Ec1 of the energy component 42a of the particle beam component which passed the 1st material part 18 of the filter part 38c, and the 1st material of the filter part 38b The energy value is the same as the energy Eb1 of the energy component 41a of the particle beam component that has passed through the portion 18.

  The particle beam irradiation apparatus 50 according to the third embodiment is different from the Bragg peak expansion filter 17 of the ninth example having the tapered hole portion 19, that is, the Bragg having the other configuration described in the first embodiment. A peak widening filter 17 can be used. For example, a configuration in which a plurality of filter elements 53a, 53b, 53c having hole portions 19 having different sizes are stacked (Bragg peak expansion filter 17 in the tenth example), a plurality of filter elements 53a having hole portions 19 having different positions, A structure in which 53b, 53c, and 53d are stacked (Bragg peak expansion filter 17 in the eleventh example), a porous structure having three-dimensional holes 19 (Bragg peak expansion filter 17 in the twelfth example), or a combination thereof Can be used. Even when the Bragg peak widening filter 17 having these configurations is used, the particle beam irradiation apparatus 50 according to the third embodiment is an irradiation target in which the distance from the body surface 36 to the bottom surface is constant like the irradiation target 11a in FIG. On the other hand, it is possible to form a uniform dose distribution. Even when the Bragg peak expansion filter 17 having these configurations is used, the particle beam irradiation apparatus 50 according to the third embodiment is different from the irradiation target 11b in FIG. 46 in that the distance from the body surface 36 to the bottom surface is different. On the other hand, it is possible to form a uniform dose distribution.

  It should be noted that the embodiments can be combined or the embodiments can be appropriately modified or omitted within a consistent range.

  DESCRIPTION OF SYMBOLS 1 ... Particle beam generation transport apparatus, 2 ... Scanning device, 6 ... Irradiation system, 9 ... Beam axis, 10, 10a, 10b, 10c ... Particle beam, 11, 11a, 11b ... Irradiation object, 12 ... Irradiation position, 17 ... Bragg peak expansion filter, 18 ... first material part, 19 ... hole, 38a, 38b, 38c ... filter part, 50 ... particle beam irradiation device, 52 ... second material part, 53a, 53b, 53c, 53d ... filter element , D ... diameter, L ... distance (center-to-center distance)

Claims (13)

A particle beam irradiation apparatus comprising: a particle beam generation and transport apparatus that generates and transports an accelerated particle beam; and an irradiation system that irradiates an irradiation target with the particle beam transported from the particle beam generation and transport apparatus. And
The irradiation system includes a scanning device that deflects the particle beam in two directions perpendicular to the beam axis of the transported particle beam, and decomposes the particle beam into a plurality of particle beam components having different energies. A Bragg peak expansion filter that expands the width in the depth direction of the Bragg peak in the irradiation object by the particle beam component,
The Bragg peak expansion filter is
A first material portion having a thickness in a direction parallel to the beam axis;
A plurality of holes disposed on the surface of the first material portion perpendicular to the beam axis, and penetrating in a direction parallel to the beam axis, or recessed in a direction parallel to the beam axis. A characteristic particle beam irradiation apparatus. The Bragg peak expansion filter has a plurality of holes arranged in a square lattice at least in part,
2. The particle beam irradiation apparatus according to claim 1, wherein the hole portions arranged in a square lattice shape are circles having respective opening shapes having the same size. The Bragg peak expansion filter has a plurality of holes arranged in a hexagonal lattice at least in part.
2. The particle beam irradiation apparatus according to claim 1, wherein the hole portions arranged in a hexagonal lattice shape are circles having the same opening shape.   3. The particle beam irradiation apparatus according to claim 2, wherein a diameter of the hole portion of the Bragg peak expanding filter is larger than 0.34 times a distance between centers of the closest hole portions.   4. The particle beam irradiation apparatus according to claim 3, wherein a diameter of the hole portion of the Bragg peak expansion filter is larger than 0.316 times a distance between the centers of the closest hole portions.   The hole portion of the Bragg peak expansion filter has an opening area on the upstream side of the beam axis and an opening area on the downstream side of the beam axis, according to any one of claims 1 to 3. Particle beam irradiation equipment. The Bragg peak expansion filter is
A second material portion made of a material different from the material of the first material portion is disposed in the hole portion of the first material portion,
7. The thickness of the first material portion in a direction parallel to the beam axis is equal to the thickness of the second material portion in a direction parallel to the beam axis. The particle beam irradiation apparatus described. The Bragg peak expansion filter is
A second material portion made of a material different from the material of the first material portion is disposed in the hole portion of the first material portion,
7. The thickness of the first material portion in a direction parallel to the beam axis is different from a thickness of the second material portion in a direction parallel to the beam axis. The particle beam irradiation apparatus described. A particle beam irradiation apparatus comprising: a particle beam generation and transport apparatus that generates and transports an accelerated particle beam; and an irradiation system that irradiates an irradiation target with the particle beam transported from the particle beam generation and transport apparatus. And
The irradiation system includes a scanning device that deflects the particle beam in two directions perpendicular to the beam axis of the transported particle beam, and decomposes the particle beam into a plurality of particle beam components having different energies. A Bragg peak expansion filter that expands the width in the depth direction of the Bragg peak in the irradiation object by the particle beam component,
The Bragg peak broadening filter is composed of a plurality of filter elements having a plane perpendicular to the beam axis,
Each said filter element is
A first material portion having a thickness in a direction parallel to the beam axis;
A plurality of holes disposed on the surface of the first material portion perpendicular to the beam axis, and penetrating in a direction parallel to the beam axis;
Each of the filter elements is different in at least one of the arrangement of the holes and the size in the direction perpendicular to the beam axis. A particle beam irradiation apparatus comprising: a particle beam generation and transport apparatus that generates and transports an accelerated particle beam; and an irradiation system that irradiates an irradiation target with the particle beam transported from the particle beam generation and transport apparatus. And
The irradiation system includes a scanning device that deflects the particle beam in two directions perpendicular to the beam axis of the transported particle beam, and decomposes the particle beam into a plurality of particle beam components having different energies. A Bragg peak expansion filter that expands the width in the depth direction of the Bragg peak in the irradiation object by the particle beam component,
The particle beam irradiation apparatus, wherein the Bragg peak widening filter has a porous three-dimensional structure having a plurality of hollow portions three-dimensionally. The Bragg peak expansion filter is
A plurality of regions having different thicknesses in a direction parallel to the beam axis of the first material portion;
The thickness of the first material portion in each of the regions is determined based on the thickness in the beam axis direction of the irradiation target irradiated with the particle beam through the first material portion. The particle beam irradiation apparatus according to any one of claims 1 to 9. The scanning device of the irradiation system comprises:
Deflecting the particle beam in two directions perpendicular to the beam axis of the particle beam transported from the particle beam generating and transporting apparatus, and scanning the particle beam at a planned verification position of the irradiation target; The particle beam irradiation apparatus according to any one of claims 1 to 11, wherein the particle beam irradiation apparatus is characterized. The scanning device of the irradiation system comprises:
Deflecting the particle beam in two directions perpendicular to the beam axis of the particle beam transported from the particle beam generating and transporting apparatus, and scanning the particle beam so as to draw a circular trajectory on the irradiation target; The particle beam irradiation apparatus according to any one of claims 1 to 11, wherein the particle beam irradiation apparatus is characterized.

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