Particle beam treatment system and control method thereof

Abstract

Provided is a particle beam treatment system capable of more effectively radiating a particle beam. This particle beam treatment system comprises: a radiation device 25 for radiating particle beams B1, B2; and a control device 40 for controlling the radiation device. The control device causes the plurality of particle beams B1, B2, which are for different purposes but are of the same type, to be radiated from the radiation device to an irradiation subject 31 at different timings.

Description

Particle beam therapy system and control method thereof

[0001] The present invention relates to a particle beam therapy system and a control method thereof.

[0002] Particle beam therapy (PBT) systems use particles such as protons or carbon ions to treat cancer. When particle beams enter the human body, a characteristic called a Bragg peak is generated, allowing the therapeutic dose to be concentrated within a narrow area. Therefore, compared to conventional photon radiation therapy, PBT can eliminate tumors while sparing the surrounding healthy tissue. To fully utilize the potential of PBT, accurate dose delivery is necessary. However, the range of particle beams (also called beams) is sensitive to the tissues they pass through, and even slight changes in the tissue can significantly alter the beam range. Therefore, obtaining the particle beam range (also called beam range) in real time during treatment is crucial for delivering an accurate dose to the affected area.

[0003] One method for determining the range of a particle beam in real time is to detect secondary radiation generated when the particle beam stops inside the patient's body (Patent Document 1). When the particle beam enters the patient's body, gamma rays are immediately emitted due to the interaction between the particle beam and the biological tissue. By detecting these gamma rays, the beam's reach (range) can be determined in real time.

[0004] On the other hand, tomography using particle beams can obtain structural information about the patient's body (Patent Document 2). The structural information inside the body can be used to predict the particle beam's flight distance and to plan treatment. Non-Patent Document 1 proposes an idea to simultaneously treat the affected area and measure the flight distance using a particle beam containing a mixture of helium and carbon.

[0005] Patent No. 6,578,282 U.S. Patent No. 10,555,709

[0006] David Mazzucconi, Stefano Agosteo, Michele Ferrarini, Luigi Fontana, Valeria Lante, Marco Pullia, and Simone Savazzi, 'Mixed particle beam for simultaneous treatment and online range verification in carbon ion therapy: Proof-of-concept study,' Medical Physics, vol. 45, no. 11, pp. 5234, 2018.

[0007] In Patent Document 1, there are problems such as a low signal-to-noise ratio of prompt gamma rays and difficulty in finding a suitable detector. In Patent Document 2, there is insufficient information on the patient's internal structure, so it is impossible to accurately determine the beam range from the body surface to the target. Therefore, in Patent Document 2, it is difficult to accurately adjust the beam energy for treating the patient.

[0008] On the other hand, the applicable area of ​​the technique described in Non-Patent Document 1 is limited by the energy ratio of the two particle beams. Furthermore, using different types of particle beams separately for distance measurement and treatment introduces additional uncertainty.

[0009] The present invention has been made in view of the above-mentioned problems, and provides a particle beam therapy system and a control method thereof that are capable of more effectively irradiating particle beams.

[0010] In order to solve the above problems, the particle beam therapy system according to the present invention includes an irradiation device that irradiates particle beams and a control device that controls the irradiation device, and the control device causes the irradiation device to irradiate multiple particle beams of the same type but for different purposes to an irradiation target at different timings.

[0011] According to the present invention, a plurality of particle beams of the same type but for different purposes can be irradiated from an irradiation device to an irradiation target at different timings.

[0012] FIG. 1 is an overall view of a particle beam therapy system. FIG. 2 is a system configuration diagram for irradiating a diseased area with a transmitted beam used for estimating a beam range and a treatment beam used for treatment at different timings. FIG. 3 is an explanatory diagram showing the relationship between the range and dose of a first beam and a second beam. FIG. 4 is an explanatory diagram showing CT imaging of a patient using 4DCT (Four-dimensional Computed Tomography). FIG. 5 is an explanatory diagram showing an example of a scanning pattern of the first beam and the second beam. FIG. 6 is an explanatory diagram showing another example of a scanning pattern of the first beam and the second beam according to a second embodiment. FIG. 7 is an explanatory diagram showing a modified example of the scanning pattern of the first beam and the second beam. FIG. 8 is an explanatory diagram showing beam irradiation using a scatterer according to a third embodiment. FIG. 9 is a flowchart of irradiation control processing according to a fourth embodiment. FIG. 10 is an overall view of a particle beam therapy system according to a fifth embodiment. FIG. 11 is an overall view of a particle beam therapy system according to a sixth embodiment.

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this disclosure, an example will be described in which multiple beams of the same type, but for different purposes, are irradiated from an irradiation device to an irradiation target at different times. In this disclosure, the irradiation range (range of range) of the beam is estimated in real time, and the energy, intensity, and irradiation angle of the therapeutic beam are controlled using the estimation result. As a result, in this disclosure, the dose of the therapeutic beam can be calculated and an accurate dose can be delivered to the affected area according to the treatment plan. Hereinafter, the range of the beam within the patient's body may be referred to as the beam range.

[0014] In the present disclosure, the first beam is used to measure the range of the beam within the body of a patient as an irradiation target. The first beam can be called a transmission beam, an imaging beam, or a range estimation beam. The second beam is used to treat the affected area. The second beam can be called a treatment beam. The first beam, which is irradiated first, estimates the spot to be set on the affected area or the beam range around the spot, and based on the estimation result, the second beam is irradiated to each spot to deliver a predetermined dose. The second beam is irradiated immediately after the irradiation of the first beam.

[0015] The first beam has a higher energy and a lower intensity than the second beam. The second beam has a lower energy and a higher intensity than the first beam.

[0016] The beam energy is the individual kinetic energy of each particle in the beam. The beam energy determines how far the particles can reach inside the body (i.e., the beam range). If the beam energy is high enough, the beam will penetrate the patient and be stopped by a detector. The beam intensity is the number of particles in the beam. The beam intensity determines how many particles are delivered to a specific location in the patient's body, i.e., the dose.

[0017] In the present disclosure, the first beam has high energy to pass through the patient's body but low intensity to minimize the dose delivered to the patient, and the second beam has low energy to stop particles at the affected area but high intensity to deliver a large dose to the affected area.

[0018] In the present disclosure, the residual energy of the first beam that has passed through the patient's body is detected, and the beam range is estimated based on the detected residual energy and information indicating the patient's internal structure. In the present disclosure, the energy, intensity, and irradiation angle of the second beam are adjusted based on the estimation result, and the second beam is irradiated to the affected area.

[0019] Information indicating the internal structure of a patient can be obtained, for example, from computed tomography (CT) images, magnetic resonance imaging (MRI) images, or X-ray images. In the present disclosure, as described below, the internal structure is imaged using 4D CT to construct a motion model and acquire the internal structure in real time.

[0020] According to the present disclosure, the beam range is estimated in real time and the second beam is controlled based on the estimation result, so that the dose to be given to the patient (affected area) can be accurately managed. Furthermore, according to the present disclosure, the dose can be accurately managed by following the patient's movements during particle beam therapy.

[0021] Example 1 will be described with reference to Figures 1 to 5. Figure 1 shows the overall configuration of a particle beam therapy system. Figure 2 shows an example configuration in which a transmitted beam used for beam range estimation and a treatment beam used for treatment are irradiated to an affected area at different times.

[0022] The particle beam therapy system includes, for example, a particle beam generator 10, a beam transport system 20, an irradiation device 25, a couch 32, and a beam irradiation controller 40. The irradiation device 25, the couch 32, and the like are arranged in a treatment room 30.

[0023] The particle beam generator 10 includes, for example, an ion source 11, a circular accelerator 12, a radio-frequency application device 13, a radio-frequency power supply 14, and an extraction septum magnet 15. The particle beam generator 10 generates multiple types of beams B1 and B2 composed of the same particles but with different energies and intensities, and supplies the beams to the irradiation device 25. As will be described later, the particle beam generator 10 can switch between generating a first beam B1 that passes through a patient 31 to perform imaging, and a second beam B2 that applies a predetermined dose to an affected area 310 (see FIG. 2 ) of the patient 31 to perform treatment. Hereinafter, the first beam B1 may be referred to as a transmitted beam B1. The second beam B2 may be referred to as a treatment beam.

[0024] The circular accelerator 12 is a device that accelerates charged particles using a time-frequency-modulated radio-frequency electric field in a main magnetic field of constant strength. The energy of the charged beam extracted from the circular accelerator 12 is variable between 70 and 235 MeV. Next, the flow of the charged beam (hereinafter referred to as the beam) from the particle beam generator 10 to the beam transport line 20 will be described.

[0025] Charged particles supplied from the ion source 11 are injected into a beam acceleration region (not shown) inside the main electromagnet (not shown) of the circular accelerator 12. The charged particles undergo circular motion within the circular accelerator 12 due to the Lorentz force from the magnetic field excited by the main electromagnet. By applying a radio frequency electric field synchronized with the period of the circular motion to the acceleration region, the energy of the charged particles increases each time they pass through the acceleration region. The radio frequency electric field is frequency-modulated in accordance with the period of the circular motion.

[0026] After the charged particles are accelerated to a predetermined energy (e.g., 70 to 250 MeV), an extraction start signal is output from the beam irradiation controller 40 to the particle beam generator 10. As a result, high-frequency power generated by the high-frequency power supply 14 is applied from a high-frequency application electrode (not shown) installed in the high-frequency application device 13 to the charged particles circulating in the circular accelerator 12. As a result, beams B1 and B2 are kicked out of their orbits by a high-frequency kicker (not shown), deflected by the extraction septum magnet 15, and extracted to the beam transport system 20.

[0027] For example, the circular accelerator 12 accelerates the beam along an eccentric orbit within a magnetic field excited by a superconducting electromagnet. Furthermore, the circular accelerator 12 is provided with a channel for extracting the beam outside the orbit convergence region through which beams of various energies commonly pass. This allows the circular accelerator 12 to extract a beam of any energy using a radio-frequency kicker. In addition to this circular accelerator 12, for example, a cyclotron, a synchrotron, or a synchrocyclotron may also be used.

[0028] The beam transport system 20 includes a plurality of quadrupole electromagnets (not shown) and a bending 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 cylindrical gantry 26 in the treatment room 30 and can rotate together with the gantry 26. The beams B1 and B2 extracted from the particle beam generator 10 are converged by the quadrupole electromagnets while passing through the beam transport system 20, and then their direction is changed by the bending electromagnet 21 before they enter the irradiation device 25.

[0029] The irradiation device 25 includes, for example, two pairs of scanning electromagnets 251 and 252, a dose monitor 254, and a position monitor 253. The two pairs of scanning electromagnets 251 and 252 are installed in directions perpendicular to each other, and can deflect the beams B1 and B2 so that the beams B1 and B2 reach desired positions in a plane perpendicular to the beam axis at the target position.

[0030] The dose monitor 254 is a monitor that measures the irradiation dose of the beams B1 and B2 irradiated onto the target. The detected measurement value is output to the beam irradiation control device 40. The position monitor 253 is a monitor that detects the passing position of the beams B1 and B2 irradiated onto the diseased part 310, which is the target, and outputs the detected detection value to the beam irradiation control device 40. The beams B1 and B2 that pass through the irradiation device 25 reach the target 310 in the patient 31, who is the irradiation subject. Note that when treating a patient with cancer or the like, the irradiation subject 31 represents the patient, and the target 310 represents a tumor or the like. The first beam B1 is used to measure the beam range at the diseased part 310, and is not used for treatment. Treatment of the diseased part 310 is performed by the second beam B2.

[0031] The bed on which the irradiation target 31 is placed is called a couch 32. The couch 32 can move in the directions of three orthogonal axes and can also rotate around each axis based on instructions from the beam irradiation control device 40. These movements and rotations allow the irradiation target 31 to be moved to a desired position.

[0032] The beam irradiation control device 40 as a "control device" is connected to, for example, the particle beam generator 10, the beam transport system 20, the irradiation device 25, the couch 32, the storage device 43, the console 44, and the treatment planning device 50. The beam irradiation control device 40 is also connected to a detection unit 33 that detects the residual energy of the first beam B1 that has passed through the patient 31, and an internal body structure information estimation device 60. The residual energy detection unit 33 is disposed directly below the patient 31. The internal body structure information estimation device 60 is an example of a device that extracts medical images. Other devices that detect respiratory phases and estimate internal body structures may also be used.

[0033] The beam irradiation control device 40 controls devices such as the particle beam generator 10, the beam transport system 20, and the irradiation device 25. The beam irradiation control device 40 includes an internal body structure information acquisition unit 41 that acquires internal body structure information indicating the internal body structure of the patient 31, a beam range estimation unit 42 that estimates the beam range, and an irradiation protocol control unit 43.

[0034] The internal body structure information acquisition unit 41 acquires internal body structure information of the patient 31 based on a detection signal from an internal body structure information estimation device 60 that estimates information indicating the internal body structure. The beam range estimation unit 42 estimates the range of the second beam B2 inside the body of the patient 31 from the residual energy of the first beam B1 detected by the residual energy detector 33 and the internal body structure information acquired by the internal body structure information acquisition unit 41. The irradiation protocol control unit 43 causes the irradiation device 25 to irradiate either the first beam B1 or the second beam B2 onto a spot SP (see FIG. 5 ) set on the target 310 in accordance with a predetermined irradiation protocol based on the estimated beam range.

[0035] Before irradiating the patient 31 with the beams B1 and B2, the beam irradiation control device 40 acquires irradiation parameters (gantry angle, planned spot data, etc.) created by the treatment planning device 50. The beam irradiation control device 40 stores the acquired irradiation parameters in the storage device 43.

[0036] The console 44 is connected to the beam irradiation control device 40 and displays information on a monitor (not shown) based on signals received from the beam irradiation control device 40. Furthermore, the console 44 receives inputs from medical personnel who operate the particle beam therapy system and transmits various control signals to the beam irradiation control device 40.

[0037] 2, a method for estimating the beam range of the second beam B2, which is a treatment beam, in real time while the patient 31 is being treated and immediately irradiating the second beam B2 to the patient 31 based on the estimation result will be described.

[0038] The irradiation protocol control unit 43 outputs a control signal to the therapist controller 432 in accordance with the irradiation protocol 431. The therapist controller 432 outputs control signals to the particle beam generator 10, the beam transport system 20, and the irradiation device 25, thereby causing the irradiation device 25 to irradiate the first beam B1 toward the patient 31.

[0039] The first beam B1 has high energy and low intensity, and therefore passes through the patient 31 and is incident on the detector 33 disposed directly below the patient 31, and its residual energy is detected by the detector 33. Since the intensity of the first beam B1 is low, the dose given to the patient 31 is small.

[0040] The residual energy of the first beam B1 detected by the detection unit 33 is input to the beam range estimation unit 42. The internal body structure information acquisition unit 41 acquires internal body structure information from the respiratory phase of the patient 31 acquired by the internal body structure information estimation device 60, etc., and inputs the information to the beam range estimation unit 42.

[0041] The beam range estimation unit 42 estimates the range (beam range) of the second beam B2 within the patient 31 based on the residual energy of the first beam B1 that has passed through the patient 31 and the internal body structure information of the patient 31 obtained by the internal body structure information acquisition unit 41. Based on the estimated beam range and the internal body structure information, the irradiation protocol control unit 43 adjusts parameters such as the energy, intensity, and irradiation angle of the second beam and causes the irradiation device 25 to irradiate the patient 31 (more precisely, the affected area 310) with the second beam B2. The number of irradiations of the first beam B1 and the number of irradiations of the second beam B2 may correspond one-to-one or one-to-many. In one example, the particle beam therapy system irradiates the affected area 310 with the second beam B2 using pencil beam scanning to provide a predetermined dose to the affected area 31. Examples of scanning patterns will be described later. The beam range estimated by the beam range estimation unit 42 can also be used for motion management, which manages the movement of the patient 31.

[0042] Alternatively, for example, 4D CT or a motion model that can describe internal body structure information at any instant may be prepared, and internal body structure information may be obtained from the motion model. Furthermore, internal body structure information may be calculated by measurements using the internal body structure information estimation device 60, such as particle-based 4D CT or a corresponding motion model. This allows for more direct correlation between internal body structure and residual energy during respiratory motion.

[0043] The accuracy of internal body structure information obtained based on non-particle measurements, such as 4DCT or a motion model based on 4DCT, can be improved by performing calibration according to the beam range based on the measured residual energy.

[0044] 3 shows the relationship between the range and the dose of the first beam B1 and the second beam B2. Since the first beam B1 has high energy, it passes through the patient 31 and enters the detector 33. However, since the first beam B1 has low intensity, its residual energy is small. The dose that the first beam B1 gives to the patient 31 is also small.

[0045] The second beam B2 has parameters such as energy, intensity, and irradiation angle adjusted based on the beam range estimated from the residual energy of the first beam B1, etc. Since the second beam B2 has low energy, it does not pass through the body of the patient 31. The end of the range of the second beam B2 is set to a predetermined location on the affected area 310, and a large dose is applied to that predetermined location.

[0046] FIG. 4 is a schematic diagram illustrating a method for performing CT imaging of a patient using a 4D CT system. An X-ray tube 61 rotates around a patient 31, and X-rays passing through the patient 31 are detected by a detector 62. Markers 63 are placed on the body surface of the patient 31, and the movement of the markers 63 is recorded by a camera 64. A 4D CT image is constructed using the signals detected by the X-ray detector 62 and the body surface movement recorded by the camera 64. The 4D CT image provides structural information about how body tissues move over time during breathing. Typically, breathing is divided into ten respiratory phases according to the amplitude of the markers 63's movement. Therefore, the positions of biological tissues in ten different respiratory phases can be determined. Information from the 4D CT image can be combined with an internal structure information estimation device 60 to obtain approximate positions of body tissues in real time. For example, the internal structure information estimation device 60 can obtain the real-time iris position at a given moment. The 4D CT phase that provides the closest diaphragm position can be identified, thereby determining the patient's 3D body structure at that moment. In another example, a model can be constructed first from 4D CT and, when combined with diaphragm (or other surrogate) movement obtained from the internal body structural information estimation device 60, real-time structural information can be available at any time during treatment.

[0047] An example of the scanning patterns of the first beam and the second beam will be described using Figure 5. The scanning patterns are managed as an irradiation protocol of the irradiation protocol control unit 43. A plurality of spots SP are set on the affected area as "irradiation areas." The upper part of Figure 5 shows a timing chart for irradiating each of the beams B1 and B2. The lower part of Figure 5 shows the scanning patterns of each of the beams B1 and B2. The scanning pattern of the first beam B1 is shown by a solid line, and the scanning pattern of the second beam is shown by a dotted line.

[0048] The first beam B1 for estimating the beam range is scanned as if filling in a certain range, while turning back and forth in the following order: spot SP1 → spot SP2 → spot SP3 → spot SP4 → spot SP5 → spot SP7 → spot SP8 → spot SP9 → spot SP10 → spot SP11 → spot SP12 → spot SP13 → spot SP14 → spot SP15 → spot SP16.

[0049] The second beam B2, which is used to deliver a predetermined dose determined in the treatment plan to the affected area, is scanned so as to follow the first beam B1. The movement trajectory of the first beam B1 coincides with the movement trajectory of the second beam B2. In the scanning pattern shown in Figure 5, the beam range is estimated for each spot SP, and the second beam is adjusted based on the estimation result.

[0050] As shown in the timing chart of Figure 5, the irradiation interval t1 of the first beam B1 and the irradiation interval t2 of the second beam B2 are the same (t1 = t2). Because the first beam B1 is irradiated before the second beam B2, the first beam B1 and the second beam B2 are irradiated at the same cycle, although there is a difference in their start times. The delay time Δt from the end of irradiation of the first beam B1 to the start of irradiation of the second beam B2 is set as short as possible. Although the time chart of Figure 5 shows the beam switching time Δt as being shorter than the beam irradiation interval t1 or t2, in reality, the beam switching time Δt is longer than the beam irradiation interval t1 or t2 (Δt >> t1, t2). This is because a long time is required for a change in beam energy.

[0051] According to this embodiment configured as described above, the beam range inside the patient's body can be estimated based on the residual energy of the first beam B1 and internal body structure information, and treatment can be performed using the second beam B2 adjusted based on the estimated beam range.

[0052] According to this embodiment, the beam range can be estimated in real time while treatment is being performed with the second beam B2, so that the prescribed dose determined in the treatment plan can be accurately applied to the affected area.

[0053] According to this embodiment, since the beam range is estimated for each spot, the accuracy of the estimation can be increased, and as a result, the irradiation parameters of the second beam B2 can be adjusted accurately.

[0054] According to this embodiment, the beam range estimated in real time can also be used for motion management, and more accurate particle beam therapy can be realized.

[0055] The particle beam therapy system of this embodiment uses multiple beams B1 and B2 made of the same type of particles but with different properties, so the range in which the beam range can be estimated and the range in which treatment can be performed can be made to almost coincide. This allows for a wider range of application than the technology described in Non-Patent Document 1, making it easier to use.

[0056] Non-Patent Document 1 claims that He2+ and C6+ can be accelerated together because their mass-to-charge ratios are the same (He2+ has a mass of 4 amu, while C6+ has a mass of 12 amu, resulting in a mass-to-charge ratio of 2). However, because the stopping force of He2+ is different from that of C6+, at a certain velocity, C6+ will stop near the tumor while He2+ will penetrate the patient. This relationship between He2+ and C6+ limits the energy range applicable to both beam range measurement and treatment. For example, when using low-energy C6+ to treat a tumor near the skin, He2+ may not have enough energy to penetrate the patient and reach the detector. Conversely, when using high-energy C6+ to treat a tumor deep within the body, He2+ may have too much energy after penetrating the patient and reach the detector. Thus, the technology proposed in Non-Patent Document 1 has limited applicability.

[0057] In contrast, the particle beam therapy system of this embodiment uses beams B1 and B2 that are made of the same particles but have different properties (energy and intensity), thereby expanding the range in which both beam range estimation and treatment can be performed, and realizing an easy-to-use particle beam therapy system.

[0058] Example 2 will be described using FIG. 6. In the following examples, including this example, differences from Example 1 will be mainly described. In this example, a first beam B1 is irradiated onto one spot in a group consisting of a predetermined number of spots among the spots SP, and a second beam B2 is irradiated onto each spot included in the group. For comparison with Example 1, Examples 1-3 share the same spot arrangement. In the time chart of FIG. 6, the beam switching time Δt is shown as being shorter than the beam irradiation interval t12, but in reality, the beam switching time Δt is longer than the beam irradiation interval t12 (Δt >> t12).

[0059] In the example shown in Figure 6, the first beam B1 is irradiated at spot SP1 to estimate the beam range, and the second beam B2 is irradiated from spots SP1 to SP7 based on the estimation result. This completes the beam range estimation and treatment for one group. Furthermore, the first beam B1 is irradiated at the next spot SP8 to estimate the beam range, and the second beam B2 is irradiated from spots SP8 to SP15 based on the estimation result. This completes the beam range estimation and treatment for the second group.

[0060] The number of spots included in each group may be the same or different. For example, one group may be composed of a small number of spots, while another group may be composed of a larger number of spots. If the time required to change the beam irradiation angle is not an issue, the first beam B1 may be irradiated to spots other than the first spot in the group to estimate the beam range, and the second beam B2 may be irradiated sequentially starting from the first spot in the group. For example, in the example of FIG. 6 , the first beam B1 may be irradiated to spot SP6 to estimate the beam range, and then the beam irradiation angle of the irradiation device 25 may be changed to spot SP1, and the second beam B2 may be irradiated from spot SP1 to spot SP7.

[0061] This embodiment configured as described above also achieves the same effects as those of the first embodiment. In this embodiment, the first beam B1 is irradiated to the first spot in the group to estimate the beam range for the entire group, and the estimated result is used to irradiate each spot in the group with the second beam B2 for treatment. Therefore, as shown in the timing chart of FIG. 6, the frequency of switching between the first beam B1 and the second beam B2 can be reduced. During the irradiation interval t11 of the first beam B1, the second beam B2 is irradiated to multiple spots. The irradiation interval t12 of the second beam B2 is substantially the same as the irradiation interval t2 in the first embodiment. Therefore, this embodiment can more efficiently switch between the first beam B1 and the second beam B2 for irradiation compared to the first embodiment.

[0062] A modification of the second embodiment will be described with reference to FIG. 7 . In this modification, as in the second embodiment, the first beam B1 is irradiated onto one spot in a group consisting of a predetermined number of spots among the spots SP, and the second beam B2 is irradiated onto each spot included in the group. In this embodiment, a zigzag scanning pattern is adopted. In the time chart of FIG. 7 , the beam switching time Δt is shown as being shorter than the beam irradiation interval t22, but in reality, the beam switching time Δt is longer than the beam irradiation interval t22 (Δt >> t22).

[0063] The modified example configured in this manner also achieves the same effects as those of Example 2. The shape of the group, the number and size of spots included in the group, and the position of each spot in the group that is irradiated with the first beam B1 to estimate the beam range can be set according to the needs of the medical technician. Note that the group configuration, the position of the spot used to estimate the beam range, and the like may be calculated using a so-called machine learning technique.

[0064] A third embodiment will be described with reference to Fig. 8. In this embodiment, each of the beams B1 and B2 is irradiated onto the patient 31 using passive beam scattering.

[0065] The beams B1 and B2 supplied from the particle beam generator 10 to the irradiation device 25 via the beam transport system 20 are incident on and scattered by the scatterer 50. The first beam B1 is scattered by the scatterer 70 and passes through the patient 31, and the beam range is estimated from the residual energy after passing through the human body and information about the internal structure. Next, the second beam B2 is scattered by the scatterer 70 and irradiated onto the affected area 310, providing a predetermined dose.

[0066] For example, the 4D CT system 60 can acquire internal body structure information, roughly estimate the positions of internal body tissues by dividing them into several phases, and use the estimation results to irradiate the second beam 2 onto the affected area 310 .

[0067] This embodiment configured as described above also achieves substantially the same effects as those of Embodiment 1. In this embodiment, the beams B1 and B2 are scattered using the scatterer 50, so that the patient can be treated while more efficiently estimating the beam range.

[0068] A fourth embodiment will be described with reference to Fig. 9. In the particle beam therapy system of this embodiment, one of the scanning patterns described in Fig. 5 and the scanning patterns described in Fig. 6 or 7 can be selected before treatment begins.

[0069] The beam irradiation control device 40 acquires a treatment plan from the storage device 43 (S10) and acquires internal body structure information from the 4DCT system 60 (S11). Furthermore, the beam irradiation control device 40 sets an irradiation protocol in accordance with the request of a medical technician who is a user of the particle beam therapy system (S12). The medical technician selects one of the scanning patterns shown in Fig. 5 and Fig. 6 or 7. That is, either a method of estimating the beam range for each spot or a method of estimating the beam range for a group including multiple spots is selected.

[0070] The beam irradiation control device 40 executes steps S14 to S19 for all spots to be irradiated as defined in the treatment plan (S13). That is, the beam irradiation control device 40 irradiates a certain spot with the first beam to obtain the residual energy (S14), and corrects the internal body structure information using the obtained residual energy (S15). Step S15 is a pre-treatment calibration. Next, the beam irradiation control device 40 irradiates the spot with the first beam again to obtain the residual energy (S16). The beam irradiation control device 40 estimates the beam range from the residual energy and the internal body structure information (S17).

[0071] The beam irradiation control device 40 sets irradiation parameters such as the energy (kinetic energy), intensity, irradiation angle, etc. of the second beam B2 based on the beam range, the internal body structure information, and the treatment plan (S18).The beam irradiation control device 40 irradiates a predetermined spot with the second beam B2 whose irradiation parameters have been adjusted (S19).

[0072] This embodiment configured in this manner also achieves the same effects as those of Embodiment 1. Furthermore, this embodiment allows the user to select between a method of estimating the beam range for each spot and a method of estimating the beam range for each group including multiple spots, thereby improving usability.

[0073] Example 5 will be described with reference to Figure 10. In this example, a particle beam generator 10(1) that generates a first beam B1 and a particle beam generator 10(2) that generates a second beam B2 are installed separately.

[0074] The beam irradiation control device 40A switches between the two particle beam generators 10(1) and 10(2) in a predetermined order to output beams B1 and B2 from the irradiation device 25A. Note that signal lines are omitted as appropriate in Figure 10 and Figure 11, which will be described later.

[0075] The present embodiment configured as described above also achieves the same effects as those of the embodiment 1. However, since the particle beam generator 10 of the embodiment 1 can output beams B1 and B2 with different properties with a single unit, the introduction cost of the particle beam therapy system of the embodiment 1 is lower.

[0076] A sixth embodiment will be described with reference to Figure 11. The particle beam generator 10B used in the particle beam therapy system of this embodiment is equipped with two extraction septum magnets (extraction ports) 15(1) and 15(2), and separate beam transport systems 20(1) and 20(2) are connected to the two extraction ports, respectively. The beam transport systems 20(1) and 20(2) are connected to an irradiation system 25B. A beam irradiation control device 40B switches between the two extraction ports 15(1) and 15(2) and the two beam transport systems 20(1) and 20(2) to use beams B1 and B2 in a predetermined order.

[0077] The present embodiment configured as described above also achieves the same effects as those of the fifth embodiment. However, in the present embodiment, since only one particle beam generator 10B is installed, the introduction cost of the particle beam therapy system can be reduced compared to the fifth embodiment.

[0078] It should be noted that the present invention is not limited to the above-described embodiments. Those skilled in the art can make various additions and modifications within the scope of the present invention. The above-described embodiments are not limited to the configuration examples shown in the accompanying drawings. The configurations and processing methods of the embodiments can be modified as appropriate within the scope of achieving the object of the present invention.

[0079] Furthermore, the components of the present invention can be selected arbitrarily, and the invention including the selected components is also included in the present invention. Furthermore, the components described in the claims can be combined in combinations other than those explicitly stated in the claims.

[0080] The following inventions are included in this disclosure:

[0081] (Representation 1) A particle beam therapy system comprising an irradiation device that irradiates particle beams and a control device that controls the irradiation device, wherein the control device irradiates multiple particle beams of the same type but for different purposes from the irradiation device to an irradiation target at different times.

[0082] (Representation 2) The particle beam therapy system according to Representation 1, wherein the plurality of different types of particle beams include a first particle beam for measuring a range of the particle beam in the irradiation target, and a second particle beam used to treat the irradiation target.

[0083] (Representation 3) A particle beam therapy system according to Representation 1 or 2, wherein the first particle beam is irradiated to the irradiation target before the second particle beam.

[0084] (Representation 4) A particle beam therapy system according to any one of Representations 1 to 3, wherein the first particle beam is a particle beam having higher energy and lower intensity than the second particle beam, and the second particle beam is a particle beam having lower energy and higher intensity than the first particle beam.

[0085] (Representation 5) The particle beam therapy system described in any one of Representations 1-4, wherein the control device estimates range information indicating the range of the second particle beam in the irradiation target based on information indicating the internal structure of the irradiation target and the residual energy when the first particle beam passes through the irradiation target, and controls the second particle beam based on the estimated range information to irradiate the second particle beam to the irradiation target.

[0086] (Representation 6) A particle beam therapy system described in any one of Representations 1-5, wherein the control device corrects information indicating the internal structure of the irradiation target based on the residual energy of the first particle beam.

[0087] (Representation 7) The particle beam therapy system according to any one of Representations 1-6, wherein the control device sets a plurality of irradiation areas for irradiating the irradiation target with particle beams, and causes the irradiation device to irradiate the first particle beam and the second particle beam for each of the irradiation areas.

[0088] (Representation 8) The particle beam therapy system according to any one of Representations 1-7, wherein the control device sets a plurality of irradiation areas for irradiating the particle beam to the irradiation target, and causes the irradiation device to irradiate the first particle beam in groups each consisting of a predetermined plurality of irradiation areas among the plurality of set irradiation areas, and causes the irradiation device to irradiate the second particle beam for each of the predetermined plurality of irradiation areas included in the group.

[0089] (Representation 9) A particle beam therapy system according to any one of Representations 1 to 8, wherein the control device is capable of selecting whether to estimate the range information for each of a plurality of irradiation areas set for irradiating the irradiation target with particle beams, or to estimate the range information for each group consisting of a predetermined plurality of irradiation areas from among the plurality of irradiation areas.

[0090] (Representation 10) A particle beam therapy system described in any one of Representations 1-9, wherein the irradiation device irradiates the first particle beam and the second particle beam to the irradiation target via a scatterer that scatters and emits the incident particle beam.

[0091] (Representation 11) A particle beam therapy system according to any one of Representations 1-10, in which the first particle beam and the second particle beam are supplied to the irradiation device from a common particle beam generator.

[0092] (Representation 12) A particle beam therapy system according to any one of Representations 1-11, further comprising a first particle beam generator that supplies the first particle beam to the irradiation device, and a second particle beam generator that supplies the second particle beam to the irradiation device.

[0093] (Representation 13) A method for controlling a particle beam therapy system comprising an irradiation device that irradiates particle beams and a control device that controls the irradiation device, wherein the control device causes the irradiation device to irradiate a plurality of different types of particle beams to an irradiation target at different timings.

[0094] 10, 10(1), 10(2), 10B: particle beam generator, 20, 20(1), 20(2): beam transport system, 25, 25A, 25B: irradiation device, 33: residual energy detector, 40, 40A, 40B: beam irradiation controller, 41: internal body structure information acquirer, 42: beam range estimator, 43: irradiation protocol controller, 50: treatment plan generator, 60: 4DCT system, B1: first beam, B2: second beam

Claims

1. A particle beam therapy system comprising an irradiation device that irradiates particle beams and a control device that controls the irradiation device, wherein the control device causes the irradiation device to irradiate multiple particle beams of the same type but for different purposes to an object at different times.

2. The particle beam therapy system according to claim 1, wherein the plurality of different types of particle beams include a first particle beam for measuring a range of the particle beam in the irradiation target, and a second particle beam used to treat the irradiation target.

3. The particle beam therapy system according to claim 2, wherein the first particle beam is irradiated to the irradiation target prior to the second particle beam.

4. The particle beam therapy system according to claim 3, wherein the first particle beam is a particle beam having higher energy and lower intensity than the second particle beam, and the second particle beam is a particle beam having lower energy and higher intensity than the first particle beam.

5. The particle beam therapy system according to claim 4, wherein the control device estimates range information indicating a range of the second particle beam in the irradiation target based on information indicating an internal structure of the irradiation target and residual energy when the first particle beam passes through the irradiation target, and controls the second particle beam based on the estimated range information to irradiate the second particle beam to the irradiation target.

6. The particle beam therapy system according to claim 5, wherein the control device corrects information indicating an internal structure of the irradiation target based on the residual energy of the first particle beam.

7. The particle beam therapy system according to claim 5, wherein the control device sets a plurality of irradiation regions for irradiating the particle beam on the irradiation target, and causes the irradiation device to irradiate the first particle beam and the second particle beam for each of the irradiation regions.

8. The particle beam therapy system according to claim 5, wherein the control device sets a plurality of irradiation areas for irradiating the particle beam to the irradiation target, causes the irradiation device to irradiate the first particle beam in groups each consisting of a predetermined plurality of irradiation areas among the plurality of set irradiation areas, and causes the irradiation device to irradiate the second particle beam for each of the predetermined plurality of irradiation areas included in the group.

9. The particle beam therapy system according to claim 5, wherein the control device is capable of selecting whether to estimate the range information for each of a plurality of irradiation areas set for irradiating the irradiation target with a particle beam, or to estimate the range information for a group unit consisting of a predetermined number of irradiation areas from among the plurality of irradiation areas.

10. The particle beam therapy system according to claim 5, wherein the irradiation device irradiates the first particle beam and the second particle beam to the irradiation target via a scatterer that scatters and emits an incident particle beam.

11. The particle beam therapy system according to claim 5, wherein the first particle beam and the second particle beam are supplied to the irradiation device from a common particle beam generating device.

12. The particle beam therapy system according to claim 5, further comprising: a first particle beam generator that supplies the first particle beam to the irradiation device; and a second particle beam generator that supplies the second particle beam to the irradiation device.

13. A method for controlling a particle beam therapy system including an irradiation device that irradiates a particle beam and a control device that controls the irradiation device, the control device causing the irradiation device to irradiate a plurality of different types of particle beams to an irradiation target at different timings.

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