JP2021040902A - Particle beam therapy apparatus, method for controlling particle beam therapy apparatus and computer program - Google Patents

Abstract

To efficiently emit a charged particle beam.SOLUTION: A particle beam therapy apparatus includes an irradiation device for irradiating multiple spots 61 set while being separated from each other in an advance direction of a charged particle beam 60 with the charged particle beam. The irradiation device irradiates each of the groups 62 including the multiple spots separated from each other in the advance direction of the charged particle beam.SELECTED DRAWING: Figure 3

Description

The present invention relates to a particle beam therapy device, a control method for the particle beam therapy device, and a computer program.

Radiation therapy damages and treats a target tumor by irradiating it with radiation. X-rays are widely used as radiation used for treatment. There is also an increasing demand for particle beam therapy using particle beams (charged particle beams) typified by proton beams and carbon beams, which have high dose concentration. The charged particle beam forms a dose distribution (black curve) with a peak at a specific depth determined by the energy of the charged particle beam. For this reason, particle beam therapy can significantly reduce the dose to normal tissue located deeper than the tumor. In radiation therapy, irradiating the tumor area with a desired dose so as to be as accurate and concentrated as possible leads to an improvement in the therapeutic effect.

In particle beam therapy, the use of scanning irradiation is expanding as a method of concentrating a dose on a target. In the scanning irradiation method, a thin charged particle beam is deflected by two sets of scanning electromagnets in an irradiation field forming apparatus and guided to an arbitrary position in a plane. Then, in the scanning irradiation method, the energy of the charged particle beam is changed to lead to an arbitrary depth in the depth direction. As a result, in the scanning irradiation method, a charged particle beam is irradiated so as to fill the inside of the tumor, and a high dose is applied only to the tumor region. The combination of the beam irradiation position (x-coordinate, y-coordinate), energy and irradiation amount is called a spot, and the arrangement of the irradiation spot and the irradiation amount are determined by the treatment planning apparatus.

JP-A-2019-133745

Int. J. Radiation Oncol. Bio. Phys, 102 (3) pp.619-626, 2018

In recent years, attention has been increasing to ultra-high dose rate irradiation called FLASH irradiation. It has been suggested that ultra-high dose irradiation may reduce toxicity to normal tissues around the tumor. The above-mentioned Non-Patent Document 1 describes a technique for realizing ultra-high dose rate irradiation by using an irradiation device in a conventional scatterer irradiation method.

In the scatterer irradiation method, the charged particle beam is expanded by irradiating the scatterer in the irradiation field forming device with the charged particle beam, and then the dose distribution is formed by using a patient-specific tool such as a bolus or a collimator. .. Therefore, in the scatterer irradiation method, it is difficult to correspond the dose distribution to a complicated tumor shape and neutrons are generated more frequently than in the scanning irradiation method in which a thin beam is scanned to form a dose distribution.

On the other hand, in the scanning irradiation method described in Patent Document 1 in which the lateral direction is the main direction, the tumor is filled by scanning the charged particle beam with a scanning electromagnet in the irradiation field forming device for each energy (irradiation depth). Irradiate as. Therefore, in the deep part of the tumor, the dose distribution is formed by the dose applied by the high-energy charged particle beam, so that the time until all the doses are applied is short and the dose rate is high. On the other hand, in the shallow position of the tumor, a dose distribution is formed by adding the dose given by the high energy beam in addition to the dose given by the low energy beam. Therefore, in the shallow position, the time until all the doses are applied becomes long, and the dose rate becomes low.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a particle beam therapy device, a control method of the particle beam therapy device, and a computer program capable of efficiently irradiating a charged particle beam. ..

In order to solve the above problems, the particle beam therapy device according to one aspect of the present invention is a particle provided with an irradiation device that irradiates a plurality of spots set apart from each other in the traveling direction of the charged particle beam. It is a line therapy device, and the irradiation device irradiates a charged particle beam for each group including a plurality of spots separated in the traveling direction of the charged particle beam.

According to the present invention, the charged particle beam can be irradiated to each group including a plurality of spots set apart from each other in the traveling direction of the charged particle beam.

It is the whole block diagram of the particle beam therapy apparatus. It is a hardware block diagram of the particle beam irradiation control device. It is explanatory drawing which shows the state of irradiating a plurality of spots arranged in the traveling direction of a charged particle beam while changing the energy of a charged particle beam. It is a flowchart which shows the particle beam irradiation process. It is explanatory drawing which shows the state of generating the data for each group from the spot data created in the treatment plan. It is explanatory drawing which shows the irradiation method of the charged particle beam which concerns on 2nd Example. It is a flowchart which shows the particle beam irradiation process. It is explanatory drawing which shows the example of the user interface screen.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, for example, the charged particle beam is applied to the accelerator 12 for accelerating the charged particle beam and the plurality of irradiation spots 61 arranged for each layer in which the irradiation target is divided into a plurality of layers in the traveling direction of the charged particle beam. An irradiation device 25 for irradiating is provided, and the irradiation device irradiates a charged particle beam for each group 62 divided into a plurality of irradiation spots so as to include irradiation spots having different layers, and within one group. When irradiating the irradiation spot with the charged particle beam, the charged particle beam is irradiated while changing the irradiation energy.

For example, in the present embodiment, a circular accelerator described in Patent Document 1 that accelerates charged particles by a high-frequency electric field that is time-frequency-modulated in a main magnetic field of constant intensity can be used. By using this accelerator to perform scanning irradiation with the depth direction as the main direction, it is possible to provide a particle beam therapy device capable of irradiating at an ultra-high dose rate even at a shallow position.

According to this embodiment, ultra-high dose rate irradiation can be realized by using the scanning irradiation method. This makes it possible to perform ultra-high dose rate irradiation that can easily deal with complicated tumor shapes and reduce the generation of neutrons.

The present embodiment can also be grasped as a device, method or computer program for creating a treatment plan. For example, in the present embodiment, a plurality of irradiation spots 61 are arranged for each layer formed by dividing the irradiation target into a plurality of layers in the traveling direction of the charged particle beam, and the plurality of irradiation spots include irradiation spots having different layers. Is divided into a plurality of groups 62, and a charged particle beam is irradiated to each of the divided groups so that the plurality of irradiation spots include irradiation spots having different layers, and the irradiation spots in one group are irradiated with the charged particle beam. A treatment planning device, method or computer program of a particle beam therapy device that creates a plan to irradiate a charged particle beam while changing the irradiation energy when irradiating.

The computer program can be stored in a storage medium in a form that can be read by a computer. The storage medium and the computer can be connected by wire or wirelessly.

The first embodiment will be described with reference to FIGS. 1 to 5. The present invention can be applied to a particle beam irradiation system such as a proton beam irradiation system or a carbon beam irradiation system, for example. In this embodiment, a proton beam irradiation system will be described as an example of the particle beam therapy device. In this embodiment, an example of a charged particle beam is a proton beam. In the embodiment, the charged particle beam may be abbreviated as a charged particle beam, a particle beam, or a beam.

The overall configuration of the particle beam therapy apparatus will be described with reference to FIG. The particle beam irradiation system as a particle beam therapy device includes, for example, a particle beam generator 10, a beam transport system 20, an irradiation device 25, a couch 33, and a particle beam irradiation control device 41.

The particle beam generator 10 includes, for example, an ion source 11, a circular accelerator 12, a high frequency application device 13, a high frequency power supply 14, and an emission septum electromagnet 15.

The circular accelerator 12 is a device that accelerates charged particles by a high-frequency electric field that is frequency-modulated in time in a main magnetic field of constant intensity. The energy of the charged particle beam extracted from the circular accelerator 12 is variable from 70 to 235 MeV. Subsequently, the flow from the particle beam generator 10 to the emission of the charged particle beam to the beam transport system 20 will be described.

The charged particles supplied from the ion source 11 are incident on the beam acceleration region (not shown) inside the main electromagnet (not shown) of the circular accelerator 12. The charged particles orbit in the circular accelerator 12 under the Lorentz force from the magnetic field excited by the main electromagnet. By applying a high-frequency electric field synchronized with the period of orbital motion to the acceleration region, the energy of the charged particles increases each time it passes through the acceleration region. The high-frequency electric field is frequency-modulated according to the period of the orbital motion.

After the charged particles are accelerated to a predetermined energy (for example, 70 to 250 MeV), the irradiation control device 41 outputs an emission start signal to the particle beam generator 10. As a result, the high-frequency power generated by the high-frequency power supply 14 is applied to the charged particle beam orbiting the circular accelerator 12 from the high-frequency application electrode (not shown) installed in the high-frequency application device 13. As a result, the charged particle beam is kicked out of the orbit, deflected by the ejection septum electromagnet 15, and emitted to the beam transport system.

The beam transport system 20 includes a plurality of quadrupole electromagnets (not shown) and a deflection electromagnet 21, and is connected to the particle beam generator 10 and the irradiation device 25. A part of the beam transport system 20 and the irradiation device 25 are installed in a substantially tubular gantry (not shown) in the treatment room 30, and can rotate together with the gantry. The charged particle beam emitted from the particle beam generator 10 is converged by the quadrupole electromagnet while passing through the beam transport system 20, changes its direction by the deflection electromagnet 21, and is incident on the irradiation device 25.

The irradiation device 25 includes, for example, two pairs of scanning electromagnets 251,252, a dose monitor 254, and a position monitor 253. The two pairs of scanning electromagnets 251,252 are installed in directions orthogonal to each other and deflect the particle beam so that the particle beam reaches a desired position in the plane perpendicular to the beam axis at the target position. Can be done.

The dose monitor 254 is a monitor that measures the irradiation amount of the particle beam irradiated to the target, and the detected measured value is output to the particle beam irradiation control device 41. The position monitor 253 is a monitor that detects the passing position of the particle beam irradiated to the target, and outputs the detected detection value to the particle beam irradiation control device 41. The particle beam that has passed through the irradiation device 25 reaches the target in the irradiation target 31. When treating a patient such as cancer, the irradiation target 31 represents a patient and the target represents a tumor or the like.

The bed on which the irradiation target 31 is placed is called a couch 33. The couch 33 can move in the directions of three orthogonal axes based on the instruction from the particle beam irradiation control device 41, and can further rotate about each axis. By these movements and rotations, the position of the irradiation target 31 can be moved to a desired position.

The particle beam irradiation control device 41 is connected to, for example, a particle beam generation device 10, a beam transport system 20, an irradiation device 25, a couch 33, a storage device 42, a console 43, a communication device 44, and the like. .. The particle beam irradiation control device 41 controls devices such as the particle beam generation device 10, the beam transport system 20, and the irradiation device 25.

The communication device 44 is connected to the data server 46 via a communication network. The communication device 44 acquires irradiation parameters (gantry angle, planned spot data, etc.) created by the treatment planning device 46 from the data server 46 via the communication network before irradiating the patient with the particle beam. The particle beam irradiation control device 41 stores the irradiation parameters received from the communication device 44 in the storage device 42.

The console 43 is connected to the particle beam irradiation control device 41, and displays information on the monitor based on the signal acquired from the particle beam irradiation control device 41. Further, the console 43 receives the input from the medical worker who operates the particle beam therapy device, and transmits various control signals to the particle beam irradiation control device 41.

An example of the case where the particle beam irradiation control device 41 is realized on a computer will be described with reference to FIG. The particle beam irradiation control device 41 includes, for example, a microprocessor (Central Processing Unit: CPU) 411, a memory 412, a communication interface unit (communication IF in the figure) 413, an auxiliary storage device 414, and an input / output unit (FIG. Medium, I / O) 416 and the like are included.

A predetermined computer program 415 is stored in the auxiliary storage device 414. When the microprocessor 411 reads the computer program 415 into the memory 412 and executes it, the function as the particle beam irradiation control device 41 is realized.

The computer program 415 may be a computer program for generating data for irradiating each spot located in the traveling direction of the particle beam by changing the energy of the particle beam in a predetermined direction. The computer program for data creation can be provided in the treatment planning device 46, or can be provided between the treatment planning device 46 and the particle beam irradiation control device 41.

The computer program 415 may be stored in the auxiliary storage device 414 from the storage medium 417 via the transmission path 418. The transmission path 418 may be wired or wireless. The transmission path 418 may be a communication network such as the Internet. The storage medium 417 is a storage medium such as a flash memory, a hard disk, an optical disk, a magnetic tape, a magnetic disk, a magneto-optical disk, or a hologram memory. Alternatively, the storage medium 417 is a memory in another computer that is communicably connected to the particle beam irradiation control device 41.

The entire computer program 415 may be stored in one storage medium 417, or a part of the computer program 415 may not be stored in the storage medium 417. The computer program 415 can realize the function as the particle beam irradiation control device 41 by cooperating with another computer program stored in the auxiliary storage device 414.

Note that FIG. 2 shows an example in which the particle beam irradiation control device 41 is configured from a single computer, but the present invention is not limited to this, and the particle beam irradiation control device 41 is physically or logically configured from a plurality of computers. You may.

In this embodiment, scanning irradiation is performed with the depth direction of the particle beam as the main direction. The depth direction is the traveling direction of the particle beam. The reachable position (depth) of the particle beam is determined by the energy of the particle beam. The higher the energy of the particle beam, the deeper the particle beam reaches. The smaller the energy of the particle beam, the shallower the position where the particle beam reaches.

In this embodiment, the dose rate at a shallow position can be improved by performing scanning irradiation with the depth direction as the main direction. The dose rate in the present specification is the time from when the first dose is given until most of the dose is given at "a certain position", and the dose given at "a certain position" is divided. It is defined as the value calculated by.

FIG. 3 is a conceptual diagram of scanning irradiation with the depth direction (z-axis direction) as the main direction. FIG. 3 shows a state in which the target 50 is illuminated with the particle beam 60 by scanning irradiation with the depth direction as the main direction.

The particle beam 60 is incident on the target 50 from the upper side to the lower side in the figure (in the z-axis direction). By changing the energy of the particle beam, the position where the particle beam reaches (the position in the z-axis direction) can be changed. In the figure, the arrival position of the particle beam becomes shallower toward the upper side, and the arrival position of the particle beam becomes deeper toward the lower side.

In the scanning irradiation in the depth direction, the spots 61 are grouped based on the irradiation positions (x-coordinate, y-coordinate) on the plane in which the particle beam 60 is incident on the target 60. Spots 61 having the same irradiation position but different only in the depth direction are treated as one group 62. That is, in the same group 62, there are spots 61 in which a plurality of energies are designated. Within the group 62, the particle beam is irradiated while changing the energy.

FIG. 3 shows a case where only the spots 61 that irradiate the same irradiation position (x-coordinate, y-coordinate) are grouped into the same group 62. In other words, one group 62 includes a plurality of spots 61 having different layers. Here, the spot located in the innermost layer is referred to as a spot 61 (1), and the spot located in the shallowest layer is referred to as a spot 61 (n).

Each group 62 includes spot 61 (1), spot 61 (2), spot 61 (3) ,. .. .. Like the spot 61 (n), a plurality of spots having different positions on the z-axis are configured as if they are stacked in order. In the figure, only spots 61 (1) and 61 (n) are shown.

Here, for the sake of explanation, a certain group among the plurality of groups 62 will be referred to as a first group 62 (1). In the first group 62 (1), the particle beam is irradiated in order from the spot 61 (1) located in the deepest layer to the spot 61 (n) located in the shallowest layer. That is, the energy of the particle beam irradiated to each spot 61 of the first group 62 (1) is controlled so as to decrease stepwise.

The group adjacent to the first group 62 (1) and irradiated with the particle beam following the first group 62 (1) is referred to as the second group 62 (2). In the second group 62 (2), contrary to the irradiation order in the first group 62 (1), the spot 61 (n) located in the shallowest layer is changed to the spot 61 (1) located in the innermost layer. The particle beam is irradiated toward it. That is, the energy of the particle beam irradiated to each spot 61 of the second group 62 (2) is controlled to increase stepwise.

When the irradiation of the particle beam to the last spot 61 (n) of the first group 62 (1) is completed, the particles are moved from the irradiation position of the first group 62 (1) to the irradiation position of the second group 62 (2) by the electromagnet. The line is scanned. Then, the energy of the particle beam is gradually increased and irradiated from the first spot 61 (n) of the second group 62 (2) toward the last spot 61 (1).

In this embodiment, the directions in which the energy of the particle beam changes are set to be opposite between the adjacent groups. When the irradiation of the last spot 61 (n) included in one group 62 (1) is completed, the position of the particle beam is scanned without changing the energy, and the first spot 61 of the next group 62 (2) is scanned. (N) is irradiated with a particle beam. Thereby, in this embodiment, the load on the particle beam generator 10 can be reduced when the irradiation position is switched (when the irradiation target group is switched).

That is, in this embodiment, the first predetermined order in which the charged particle beam 60 is applied to the plurality of spots 61 (1) to 61 (n) included in the first group 62 (1) and the first group 62. A second group 62 (2) to which the charged particle beam 60 is irradiated following the (1), and charged particles to a plurality of spots 61 (n) to 61 (1) included in the second group 62 (2). The line 60 is set in the opposite direction to the second predetermined order of irradiation.

If the energy efficiency or load of the particle beam generator 10 is not considered to be a problem, the direction of change in the energy of the particle beam in all the groups 62 can be arbitrarily set. For example, in one group and the other groups following it, the energy of the particle beam is gradually changed from a low value to a high value, so that the spot located in the shallow layer 61 (n) is located in the deep layer. By irradiating the particle beam in order up to 61 (1), and in yet another group, by gradually changing the energy of the particle beam from a high value to a low value, the spot 61 (1) located in the deep layer to the shallow layer The particle beam may be irradiated in order up to the spot 61 (n) located at.

In this embodiment, by changing the energy of the particle beam 60, the first scan for sequentially irradiating the spots 61 arranged along the traveling direction of the particle beam 60 and the irradiation position (irradiation target group) are switched. By performing the second scan in sequence, a predetermined dose can be effectively given to the target. Then, as described above, in the present embodiment, the order of changing the energy of the particle beam (the order of descending or ascending) is reversed from the order of changing the immediately preceding group, thereby causing the particle beam generator 10. The load can be reduced.

The particle beam irradiation process will be described with reference to the flowchart of FIG. In the following, the procedure for performing scanning irradiation with the depth direction as the main direction and the operation of the particle beam therapy device will be described.

First, the medical worker fixes the patient who is the irradiation target 31 on the couch 33. After that, the medical worker moves the irradiation target 31 to a predetermined position by moving the couch 33. The medical staff confirms that the irradiation target 31 has moved to a predetermined position by capturing an image of the affected portion of the patient using an X-ray imaging device or the like (not shown).

When the medical worker instructs the irradiation preparation using the console 43, the particle beam irradiation control device 41 reads the irradiation parameters (gantry angle, planned spot data, etc.) from the storage device 42 (S11).

Here, the planning spot is data created by the treatment planning device 46, and represents a set of an irradiation position, energy, and an irradiation amount. At the stage of step S11 for reading the planned spot data, as shown in the table T1 in FIG. 5, the planned spot data is stored in a state sorted by energy.

The healthcare professional then selects either the lateral or depth direction as the primary scanning direction. When the depth direction is selected as the main direction, the planned spot data is grouped (S12). In this embodiment, only spots 61 that irradiate the same irradiation position (x, y) and have different energies are treated as the same group 62.

As shown in the table T2 in FIG. 5, the particle beam irradiation control device 41 sorts the planned spot data for each irradiation position. Here, the order of the spot irradiation positions retains the order at the time of reading the planned spot data. Further, in order to reduce the load on the particle beam generator 10, the sort order of the energies in the group of adjacent irradiation positions is reversed. After grouping the planned spot data, the grouped spot data is stored in the storage device (S13).

Subsequently, a medical worker such as a radiological technologist rotates the gantry by pressing the gantry rotation button from the console 43 according to the gantry angle described in the irradiation parameter.

After the rotation of the gantry, when the medical worker presses the irradiation start button on the console 43, the particle beam irradiation control device 41 first receives the energy read from the storage device 42, the irradiation position, and the irradiation amount information. The particle beam is accelerated to the energy to be irradiated (S14).

For example, the particle beam irradiation control device 41 controls the ion source 11 and the circular accelerator 12 to accelerate the particle beam generated by the ion source 11 to the energy of first irradiation. The particles orbiting the circular accelerator 12 are accelerated each time they pass through the acceleration region by applying a high-frequency electric field synchronized with the period of the orbiting motion to the acceleration region (not shown) of the circular accelerator.

Next, the particle beam irradiation control device 41 uses the deflection electromagnet 21, the quadrupole electromagnet, and the ejection septum electromagnet of the beam transport system 20 so that the particle beam of the energy to be irradiated first can reach the irradiation device 25 from the particle beam generator 10. The amount of excitation with 15 is controlled (S15).

The particle beam irradiation control device 41 excites two scanning electromagnets 251,252 in the irradiation device 25 so that the particle beam reaches the spot position of the first group of the planned spot data stored in the storage device 42. The amount is set (S16).

After completing these settings, the particle beam irradiation control device 41 applies a high frequency to the high frequency applying device 13 to start emitting particle beams (S17). When a high frequency is applied to the high frequency applying device 13, the particle beam orbiting in the circular accelerator 12 is kicked out from the orbit, deflected by the ejection septum electromagnet 15, passes through the beam transport system 20, and is passed through the beam transport system 20 to the irradiation device 25. To reach. The particle beam that has reached the irradiation device 25 passes through the dose monitor 254 and the position monitor 253, reaches the target 50 in the irradiation target 31, and forms a dose distribution.

The irradiation amount for each spot is registered in the planned spot data. When the irradiation amount measured by the dose monitor 254 reaches the registered value, the particle beam irradiation control device 41 stops the emission of the particle beam by controlling the emission high frequency.

The circular accelerator 12 can accelerate the particle beam generated by the ion source 11 in a certain period. This cycle is called the acceleration cycle. When the spot 61 exists in the same group 62 (S18: YES), the particle beam irradiation control device 41 waits until the next acceleration cycle after stopping the emission (S19).

After the standby, the particle beam irradiation control device 41 accelerates the particle beam generated by the ion source 11 to the energy specified by the particle beam of the next spot, and until the irradiation of all the spots in the group is completed. The processes of steps S14 to S19 are repeated.

When the particle beam irradiation control device 41 completes irradiation to all the spots in the same group (S18: NO), it determines whether the next group exists (S20), and if the next group exists (S20: NO). YES), the process waits until the next acceleration cycle (S19), and the processes of steps S14 to S20 are repeated so that the first spot of the next group can be irradiated with the beam. This process is completed when the irradiation of all spots in all groups is completed.

In this embodiment, in the planned spot data, those having the same irradiation position have been described as the same group, but those having the same irradiation position do not necessarily have to be in the same group. For example, in the operation of the treatment planning device 46, the spot interval of the planned spot data may differ between energies. In this case, it is also possible to set the threshold distance and set the spot data in which the difference in irradiation positions is equal to or less than the threshold distance as the same group.

It is also possible for the medical staff to manually specify the range of the irradiation position in the lateral direction (x-coordinate, y-coordinate) to group the spots. At this time, a plurality of spots having the same energy may exist in the group. This example will be described later as another embodiment.

According to the present embodiment configured in this way, the first scan (also referred to as vertical scan) in which the particle beam is scanned while changing the energy along the traveling direction (z coordinate) of the particle beam, and the particle beam A predetermined dose distribution can be realized by a second scan (also called a lateral scan) that changes the irradiation position (x-coordinate, y-coordinate). Therefore, according to this embodiment, ultra-high dose rate irradiation can be realized by using the scanning irradiation method. This makes it easy to deal with complicated tumor shapes and enables ultra-high dose rate irradiation that can reduce the generation of neutrons.

It is also possible to set a plurality of groups 62 having different irradiation directions of particle beams to the same target 50.

The second embodiment will be described with reference to FIGS. 6 to 8. In each of the following examples including this embodiment, the differences from the first embodiment will be mainly described. In this embodiment, the concept of a group is extended to include a plurality of spots 61 irradiated with the same energy in one expansion group 501.

FIG. 6 shows how three expansion groups 501A, 501B, and 501C are set for the target 50. When expansion groups 501A, 501B, and 501C are not distinguished, they are referred to as expansion groups 501 or group 501.

In the expansion group 501, a plurality of spots 61 are set for each layer. In FIG. 6, the spot belonging to the expansion group 501A is referred to as a spot 61A, the spot belonging to the expansion group 501B is referred to as a spot 61B, and the spot belonging to the expansion group 501C is referred to as a spot 61C. When no distinction is made, it is called a spot 61. For each spot, the layer to which the spot belongs is indicated by a number in parentheses. For example, spot 61A (1) is a spot located in the innermost layer (deepest layer) in the expansion group 501A. The number of expansion groups 501 is not limited to three. The target 50 can have two expansion groups or four or more expansion groups. Further, expansion groups having different irradiation directions of particle beams can be set to the same target 50.

In each expansion group 501, all spots 61 are irradiated with particle beams in a lateral scan for each layer. As described above, the lateral scan is to irradiate the particle beam in the same layer by changing only the irradiation position (x-coordinate, y-coordinate) without changing the energy of the particle beam.

In the expansion group 501, when the irradiation of all the spots 61 of a certain layer with the particle beam is completed, the energy of the particle beam is changed and the layer to be irradiated is switched. In the expansion group 501, the entire plurality of spots 61 included in the same layer are treated as if they were one virtual spot (extension spot).

The operation of the particle beam irradiation control device 41 will be described in the flowchart of FIG. 7. In this embodiment, as described above, a horizontal scan is performed within each layer of the extended group 501, and a vertical scan is performed between the layers.

In the flowchart of FIG. 7, the operation until the first spot is irradiated is the same as the operation flow shown in FIG. 4 (S11 to S17).

In this embodiment, when a plurality of spots 61 having the same energy exist in one group 501, it is determined whether or not unirradiated spots 61 having the same energy exist in the group 501 before changing the energy of the particle beam. S31). When the spot 61 to be irradiated with the particle beam of the same energy exists in the same group 501 (S31: YES), the particle beam irradiation control device 41 returns to step S16 and scans the beam with the scanning electromagnet to step. The spot detected in S31 is irradiated with a particle beam (S16 to S31). In this way, the particle beam irradiation control device 41 irradiates all spots belonging to the same layer (plane on which particle beams of the same energy are irradiated) in the same group with particle beams.

For example, the particle beam irradiation control device 41 sets the excitation amounts of the two scanning electromagnets 251,252 in the irradiation device 25 so that the beam can be irradiated to the irradiation position of the next spot (S15). The particle beam irradiation control device 41 repeats the processes of steps S15 and S16 until the irradiation of spots having the same energy in the group 501 is completed.

When the irradiation of the particle beam to the spots having the same energy in the group 501 is completed, the particle beam irradiation control device 41 determines whether there are spots having different energies (S32), and when the energy needs to be changed (S32: YES), the process waits until the next acceleration cycle (S19), and the processes from step S14 to step S31 are repeated.

When the irradiation of all the spots in the group 501 is completed, the particle beam irradiation control device 41 determines whether the group 501 to be processed exists (S33), and if the unprocessed group exists (S33: YES), the unprocessed group 501 exists. The processing from step S14 to step S33 is repeated until all the spots included in the processing group are irradiated with the particle beam. When the particle beam irradiation control device 41 irradiates all the spots of all the groups 501 set on the target 50 with the particle beam, the present process ends.

In order to reduce the load on the particle beam generator 10, when switching the irradiation from one group 501 to the next group, the energy change order may be set in the opposite direction. For example, in group 501A, the particle beam may be irradiated in the order of high energy to low energy, and in group 501B following group 501A, the particle beam may be irradiated in the order of low energy to high energy.

When grouping the spots 61, the medical staff can manually specify the range of each group by using an input device such as a mouse on the user interface screen provided by the console 43. When manually setting the group, for example, past history data or reference information such as the result of machine learning may be presented on the user interface screen to support the judgment of the medical staff.

FIG. 8 is an example of the user interface provided by the console 43. The group setting screen 70 includes, for example, a spot position display unit 71, a display energy selection unit 72, and an energy change order selection unit 73. The spot position display unit 71 displays the positions of all the spots as seen from the BEV (Beams Eye View).

The spots of each energy are displayed in different colors for each energy. An operator such as a medical worker sets a group boundary using an input device such as a mouse while observing the spot position displayed on the display unit 71. In the figure, two groups 501, a first group and a second group, are set.

The operator can also select one or more arbitrary energies in the display energy selection unit 72 and set the group boundary based on the selected energies.

When the operator completes the group boundary setting, the operator sets the energy change order within each group 501. The upward arrow indicates that the energy is changed in the increasing direction. The downward arrow indicates that the energy is changed in the decreasing direction. When the operator specifies that the energy change order between adjacent groups having continuous irradiation orders is reversed, the load on the particle beam generator 10 can be reduced and the dose rate can be further increased. It becomes.

Up to this point, an example in which the group 501 is designated in the console 43 has been described, but the group 501 may be designated in the treatment planning device 46. Further, the treatment planning device 46 may be used to simulate the dose rate, and the operator may specify the group while confirming the dose rate predicted by the simulation.

This embodiment configured in this way also has the same effect as that of the first embodiment. Further, in this embodiment, since the expansion group 501 including a plurality of spots having the same energy is set as the target 50, the dose distribution can be formed more efficiently.

The present invention is not limited to the above-described embodiment. A person skilled in the art can make various additions and changes within the scope of the present invention. In the above-described embodiment, the configuration is not limited to the configuration example shown in the accompanying drawings. The configuration and processing method of the embodiment can be appropriately changed within the range of achieving the object of the present invention.

In the present embodiment, the case where the energy of the particle beam is changed by controlling the circular accelerator 12 has been described, but the present invention is not limited to this, and the energy of the particle beam may be changed by using an energy attenuator such as a degrader. Good.

Further, the expansion group setting method may be changed manually or automatically according to a predetermined parameter such as the angle of the rotating gantry or the irradiation date. This facilitates ensuring a predetermined dose near the boundaries between the extended groups.

In addition, each component of the present invention can be arbitrarily selected, and an invention having the selected configuration is also included in the present invention. Further, the configurations described in the claims can be combined in addition to the combinations specified in the claims.

10: Particle beam generator, 11: Ion source, 12: Circular accelerator, 13: High frequency application device, 14: High frequency power supply, 15: Septum electromagnet for emission, 20: Beam transport system, 25: Irradiation device, 41: Particle beam Irradiation control device, 43: console, 46: treatment planning device

Claims (12)

A particle beam therapy device including an irradiation device that irradiates a plurality of spots set apart in the traveling direction of the charged particle beam with the charged particle beam.
The irradiation device irradiates the charged particle beam for each group including a plurality of spots separated in the traveling direction of the charged particle beam.
Particle beam therapy device. The irradiation device irradiates a plurality of spots separated in the traveling direction of the charged particle beam in a predetermined order by changing the energy of the charged particle beam.
The particle beam therapy apparatus according to claim 1. A first predetermined order in which charged particle beams are irradiated to a plurality of spots included in the first group, and a second group in which charged particle beams are irradiated following the first group, the second group. It is set in the reverse direction of the second predetermined order in which the charged particle beam is applied to the plurality of spots included in the.
The particle beam therapy apparatus according to claim 2. When switching between irradiation of the plurality of spots included in the first group with the charged particle beam and irradiation of the plurality of spots included in the second group with the charged particle beam, the charged particle beam is scanned and the irradiation direction is obtained. Is changed,
The particle beam therapy apparatus according to claim 3. When the irradiation device includes a plurality of predetermined spots to which a charged particle beam of a predetermined energy is irradiated in each group, the irradiation device scans the charged particle beam of the predetermined energy to the plurality of predetermined spots. Irradiate a charged particle beam with a predetermined energy,
The particle beam therapy apparatus according to claim 1. The boundaries of each of the groups can be changed.
The particle beam therapy apparatus according to claim 5. A computer program that causes a computer to function as a particle beam therapy device including an irradiation device that irradiates a plurality of spots set apart from each other in the traveling direction of the charged particle beam.
A data acquisition function that acquires spot data included in the treatment plan,
Based on the acquired spot data, a group generation function for generating a group of spot data including a plurality of spots separated in the traveling direction of the charged particle beam from the irradiation device, and a group generation function.
An irradiation function for irradiating a charged particle beam from the irradiation device for each of the generated groups.
A computer program realized on the computer. The irradiation device irradiates a plurality of spots separated in the traveling direction of the charged particle beam in a predetermined order by changing the energy of the charged particle beam.
A first predetermined order in which charged particle beams are irradiated to a plurality of spots included in the first group, and a second group in which charged particle beams are irradiated following the first group, the second group. It is set in the reverse direction of the second predetermined order in which the charged particle beam is applied to the plurality of spots included in the.
The computer program according to claim 7. When each of the groups includes a plurality of predetermined spots to be irradiated with the charged particle beam of a predetermined energy, the predetermined spot is subjected to the predetermined spot by scanning the charged particle beam of the predetermined energy with the irradiation device. The computer program according to claim 8, wherein the charged particle beam of energy is irradiated. It is a control method for particle beam therapy equipment.
The particle beam therapy device includes an irradiation device that irradiates a plurality of spots set apart from each other in the traveling direction of the charged particle beam with the charged particle beam.
Acquire spot data including multiple spots to be irradiated with charged particle beams,
Based on the acquired spot data, a group including a plurality of spots separated in the traveling direction of the charged particle beam is generated.
Save the generated group and
The irradiation device irradiates the charged particle beam for each group.
A method for controlling a particle beam therapy device. The irradiation device irradiates a plurality of spots separated in the traveling direction of the charged particle beam in a predetermined order by changing the energy of the charged particle beam.
A first predetermined order in which charged particle beams are irradiated to a plurality of spots included in the first group, and a second group in which charged particle beams are irradiated following the first group, the second group. It is set in the reverse direction of the second predetermined order in which the charged particle beam is applied to the plurality of spots included in the.
The method for controlling a particle beam therapy apparatus according to claim 10. When each of the groups includes a plurality of predetermined spots to be irradiated with charged particle beams of a predetermined energy, the predetermined spots are subjected to the predetermined spots by scanning the charged particle beams of the predetermined energy with the irradiation device. The method for controlling a particle beam therapy device according to claim 11, wherein a charged particle beam of energy is irradiated.

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