Particle beam therapy system and control method therefor

Abstract

To provide a particle beam therapy system that can more effectively apply particle beams.SOLUTION: A particle beam therapy system comprises an irradiation device 25 for applying particle beams B1 and B2, and a control device 40 for controlling the irradiation device. The control device applies the particle beams B1 and B2 of the same kind having different applications to an irradiation object 31 from the irradiation device at different timings.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Particle beam therapy (PBT) systems use particles such as protons or carbon ions to treat cancer. When particle beams enter the human body, they produce a characteristic called a Bragg peak, which allows the therapeutic dose to be concentrated in a narrow area. Therefore, compared to conventional photon beam radiation therapy, PBT can destroy tumors while sparing most of the surrounding healthy tissue. To fully utilize the potential of PBT, it is necessary to ensure accurate dose delivery. However, the range of particle beams (also called beams) is easily affected by the body tissues they pass through, so even a slight change in the tissues can significantly change the beam range. Therefore, obtaining the range (also called beam range) of the particle beam in real time during treatment is important to deliver an accurate dose to the affected area.

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

[0004] On the other hand, structural information of a patient's body can be obtained by tomography using particle beams (Patent Document 2). The internal structural information can be used to predict the distance the particle beam will travel and can be used in treatment planning. Non-Patent Document 1 proposes the idea of ​​using a particle beam containing a mixture of helium and carbon to simultaneously treat the affected area and measure the distance traveled. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6578282 specification [Patent Document 2] U.S. Pat. No. 10,555,709 [Non-patent literature]

[0006] [Non-Patent Document 1] Davide 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. Summary of the Invention [Problem to be solved by the invention]

[0007] In Patent Document 1, there are problems with the low signal-to-noise ratio of prompt gamma rays and the difficulty in finding suitable detectors. In Patent Document 2, since the patient's internal structure information is insufficient, the beam range from the body surface to the target cannot be accurately known. 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 problems, and provides a particle beam therapy system and a control method thereof that are capable of more effectively irradiating particle beams. [Means for solving the problem]

[0010] In order to solve the above problems, the particle beam therapy system according to the present invention includes an irradiation device that irradiates a particle beam 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. Effect of the Invention

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

[0012] [Figure 1] Overall diagram of the particle beam therapy system. [Diagram 2] FIG. 1 is a diagram showing the system configuration for irradiating an affected area with a transmitted beam used for estimating a beam range and a treatment beam used for treatment at different timings. [Diagram 3] FIG. 4 is an explanatory diagram showing the relationship between the range and the dose of the first beam and the second beam. [Figure 4] An explanatory diagram showing how a patient is scanned using 4DCT (Four-dimensional computed tomography). [Diagram 5] FIG. 4 is an explanatory diagram showing an example of a scanning pattern of a first beam and a second beam. [Figure 6] FIG. 11 is an explanatory diagram showing another example of the scanning pattern of the first beam and the second beam in the second embodiment. [Figure 7] 10A and 10B are explanatory diagrams showing modified examples of the scanning patterns of the first beam and the second beam. [Figure 8] FIG. 11 is an explanatory diagram showing how a beam is irradiated using a scatterer in the third embodiment. [Figure 9]13 is a flowchart of an irradiation control process in the fourth embodiment. [Figure 10] FIG. 13 is an overall view of a particle beam therapy system according to a fifth embodiment. [Figure 11] FIG. 13 is an overall view of a particle beam therapy system according to a sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 with different uses, are irradiated from an irradiation device to an irradiation target at different timings. In this disclosure, the irradiation range (range of the beam) 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 inside 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 energy of the beam is the individual kinetic energy of each particle in the beam. The energy of the beam determines how far into the body the particles can penetrate (i.e., the beam range). If the beam has enough energy, it will penetrate the patient and be stopped at a detector. The intensity of the beam is the number of particles in the beam. The intensity of the beam determines how many particles are delivered to a particular location in the patient, i.e., the dose.

[0017] In this disclosure, the first beam is made high energy to pass through the patient's body but low intensity to minimize the dose delivered to the patient, and the second beam is made low energy to stop the 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 a computed tomography (CT) image, a magnetic resonance imaging (MRI) image, an X-ray image, etc. In the present disclosure, as described below, the internal structure is photographed using 4DCT, a motion model is constructed, and a real-time internal structure is obtained.

[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 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 movement of the patient during particle beam therapy. EXAMPLES

[0021] A first embodiment will be described with reference to Fig. 1 to Fig. 5. Fig. 1 shows the overall configuration of a particle beam therapy system. Fig. 2 shows a configuration example in which a transmitted beam used for estimating a beam range and a treatment beam used for treatment are irradiated to an affected area at different timings.

[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 high-frequency application device 13, a high-frequency power supply 14, and an extraction septum magnet 15. The particle beam generator 10 generates a plurality of types of beams B1 and B2 made of the same particles and different in energy and intensity, and supplies them to the irradiation device 25. As described later, the particle beam generator 10 can switch between generating a first beam B1 that passes through a patient 31 to take an image, and a second beam B2 that applies a predetermined dose to an affected area 310 (see FIG. 2) of the patient 31 to treat the affected area. 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 by a radio frequency electric field that is frequency modulated over time 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, a flow of the charged beam (hereinafter, 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 high-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 high-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 (for example, 70 to 250 MeV), an extraction start signal is output from the beam irradiation control device 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, the beams B1 and B2 are kicked out of the orbit by a high-frequency kicker (not shown), deflected by the extraction septum electromagnet 15, and extracted to the beam transport system 20.

[0027] For example, the circular accelerator 12 accelerates the beam along an eccentric orbit in 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 the beams of each energy pass in common. This allows the circular accelerator 12 to extract a beam of any energy by a radio-frequency kicker. In addition to the circular accelerator 12, for example, a cyclotron, a synchrotron, a synchrocyclotron, etc. may 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 emitted 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 entering 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 dose of the beams B1 and B2 irradiated to 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 to 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 have passed through the irradiation device 25 reach the target 310 in the patient 31, which is the irradiation subject. In addition, 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 range of the beam at the diseased part 310, and is not used for treatment. The 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 the 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. By these movements and rotations, the position of the irradiation target 31 can 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 plan creation device 50. Furthermore, 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 to 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 structure information acquisition unit 41 acquires internal structure information of the patient 31 based on a detection signal from an internal structure information estimation device 60 that estimates information indicating the internal 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 structure information acquired by the internal 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 to 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] The beam irradiation control device 40 acquires irradiation parameters (gantry angle, planned spot data, etc.) created by the treatment plan creation device 50 before irradiating the beams B1 and B2 to the patient 31. 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 acquired 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] A method of 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 with reference to FIG.

[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 enters the detection unit 33 arranged directly below the patient 31, and the residual energy is detected by the detection unit 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 based on the respiratory phase of the patient 31 acquired by the internal body structure information estimation device 60, 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 in the body of the patient 31 based on the residual energy of the first beam B1 that has passed through the body of the patient 31 and the internal structure information of the patient 31 obtained by the internal structure information acquisition unit 41. Based on the estimated beam range and the internal 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 by pencil beam scanning, and gives a predetermined dose to the affected area 31. An example of a scanning pattern will be described later. The beam range estimated by the beam range estimation unit 42 can also be used for motion management that manages the movement of the patient 31.

[0042] For example, a motion model that can describe 4DCT or internal structure information at any moment may be prepared, and internal structure information may be obtained from the motion model. Furthermore, internal structure information may be calculated by measurements by the internal structure information estimation device 60, such as particle-based 4DCT or a corresponding motion model. This makes it possible to obtain a more direct correlation between the internal structure during respiratory motion and the residual energy.

[0043] For internal body structure information obtained based on non-particle measurements, such as 4DCT or a motion model based on 4DCT, the accuracy of the internal body structure information 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 detection unit 33. However, since the first beam B1 has low intensity, its residual energy is small. The dose given to the patient 31 by the first beam B1 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. 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 in the affected area 310, and a large dose is applied to the predetermined location.

[0046] FIG. 4 is a schematic diagram showing a method of CT imaging of a patient using a 4DCT 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. A marker 63 is placed on the body surface of the patient 31, and the movement of the marker 63 is recorded by a camera 64. Then, a 4DCT is constructed using the signal detected by the X-ray detector 62 and the movement of the body surface recorded by the camera 64. The 4DCT 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 movement of the marker 63. Thus, the positions of biological tissues in ten different respiratory phases can be obtained. Information from the 4DCT 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 certain moment. The phase of the 4DCT that gives the closest diaphragm position can be identified, thereby determining the 3D body structure of the patient at that moment. In another example, a model may be constructed first from 4DCT and, when combined with diaphragm (or other surrogate) movement obtained from the internal structure information estimation device 60, real-time structural information may be available at any time during treatment.

[0047] An example of the scanning pattern of the first beam and the second beam will be described with reference to FIG. 5. The scanning pattern is managed as an irradiation protocol of the irradiation protocol control unit 43. A plurality of spots SP are set as "irradiation regions" on the affected area. The upper side of FIG. 5 shows a timing chart of the irradiation of each of the beams B1 and B2. The lower side of FIG. 5 shows the scanning pattern 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 area, by turning around 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 prescribed dose to the affected area as determined by the treatment plan, is scanned so as to follow the first beam B1. The movement trajectory of the first beam B1 and the movement trajectory of the second beam B2 coincide with each other. In the scanning pattern shown in Figure 5, the beam range is estimated for each spot SP, and the second beam adjusted based on the estimation result is irradiated.

[0050] As shown in the timing chart of FIG. 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). Since the first beam B1 is irradiated before the second beam B2, the first beam B1 and the second beam B2 are irradiated in the same cycle, although there is a difference in their starting 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. In the time chart of FIG. 5, the beam switching time Δt is shown as if it were shorter than the beam irradiation interval t1 or t2, but in reality, the beam switching time Δt is longer than the beam irradiation interval t1 or t2 (Δt>>t1, t2). This is because it takes a long time to change the beam energy.

[0051] According to this embodiment configured in this manner, 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, since the beam range can be estimated in real time while performing treatment with the second beam B2, a predetermined 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 improved, 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, making it possible to realize even more accurate particle beam therapy.

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

[0056] In Non-Patent Document 1, it is claimed that He2+ and C6+ have the same mass-to-charge ratio (He2+ has a mass of 4 amu, C6+ has a mass of 12 amu, and both have a mass-to-charge ratio of 2), so they can be accelerated together. However, the stopping power of He2+ is different from that of C6+, so when He2+ and C6+ reach a certain speed, C6+ stops near the tumor and He2+ penetrates the patient. Because of this relationship between He2+ and C6+, the energy range that can be applied to both beam range measurement and treatment is limited. 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 inside, He2+ may reach the detector because its energy after penetrating the patient is too strong. Thus, the technology proposed in Non-Patent Document 1 has a limited range of 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), so that the range in which both beam range estimation and treatment can be performed can be expanded, thereby realizing an easy-to-use particle beam therapy system. EXAMPLES

[0058] Example 2 will be described with reference to FIG. 6. In the following examples including this example, differences from Example 1 will be mainly described. In this example, the first beam B1 is irradiated to one spot in a group unit consisting of a predetermined number of spots among the spots SP, and the second beam B2 is irradiated to each spot included in the group. For comparison with Example 1, Examples 1-3 have the same spot arrangement. In the time chart of FIG. 6, the beam switching time Δt is shown as if it were 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 Fig. 6, the first beam B1 is irradiated at spot SP1 to estimate the beam range, and the second beam B2 is irradiated from spot SP1 to spot SP7 according to 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 spot SP8 to spot SP15 according to 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, and another group may be composed of a larger number of spots. If the time to change the beam irradiation angle is not an issue, the first beam B1 may be irradiated to spots other than the first spot of the group to estimate the beam range, and the second beam B2 may be irradiated in order from the first spot of the group. For example, in the example of FIG. 6, after the first beam B1 is irradiated to the spot SP6 to estimate the beam range, the beam irradiation angle of the irradiation device 25 may be changed to the spot SP1, and the second beam B2 may be irradiated from the spot SP1 to the spot SP7.

[0061] The present embodiment thus configured also achieves the same effects as those of the first embodiment. In this embodiment, the first beam B1 is irradiated at the first spot of the group to estimate the beam range of the entire group, and the estimated result is used to irradiate each spot in the group with the second beam B2 for treatment, so that the frequency of switching between the first beam B1 and the second beam B2 can be reduced, as shown in the timing chart of FIG. 6. 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 approximately the same as the irradiation interval t2 of the first embodiment. Therefore, in this embodiment, the first beam B1 and the second beam B2 can be switched and irradiated more efficiently than in the first embodiment.

[0062] A modified example of the second embodiment will be described with reference to FIG. 7. In this modified example, as in the second embodiment, the first beam B1 is irradiated onto one spot in a group unit 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 if it were 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 has the same effect as that of Example 2. The shape of the group, the number of spots included in the group, the size of the spots, the position of the spot among the spots in the group to be irradiated with the first beam B1 to estimate the beam range, and the like can be set according to the requirements of a medical technician. Note that the configuration of the group, the position of the spot used to estimate the beam range, and the like may be calculated using a so-called machine learning technique. EXAMPLES

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

[0065] Each of the beams B1 and B2 supplied from the particle beam generator 10 to the irradiation device 25 via the beam transport system 20 is incident on the scatterer 50 and scattered. 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 internal structure information. Next, the second beam B2 is scattered by the scatterer 70 and irradiated to the affected area 310 to give a predetermined dose.

[0066] For example, internal body structure information can be acquired by the 4DCT system 60, the positions of internal body tissues can be roughly estimated in several phases, and the second beam 2 can be irradiated to the affected area 310 using the estimation results.

[0067] The present embodiment thus configured also has almost the same effects as those of embodiment 1. In this embodiment, the beams B1 and B2 are scattered by the scatterer 50, so that the patient can be treated while estimating the beam range more efficiently. EXAMPLES

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

[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 according to a request from a medical technician who is a user of the particle beam therapy system (S12). The medical technician selects one of the scanning patterns described in Fig. 5 and the scanning patterns described in Fig. 6 or 7. That is, either a method of estimating a beam range for each spot or a method of estimating a beam range for each 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 determined 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 structure information using the obtained residual energy (S15). Step S15 is a pre-treatment calibration. Next, the beam irradiation control device 40 irradiates the first beam again and obtains the residual energy (S16). The beam irradiation control device 40 estimates the beam range from the residual energy and the internal 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 structure information, and the treatment plan (S18). The beam irradiation control device 40 irradiates the second beam B2, the irradiation parameters of which have been adjusted, to a predetermined spot (S19).

[0072] The present embodiment configured as above also has the same operational effects as those of Example 1. Furthermore, in the present embodiment, it is possible to select either a method of estimating the beam range for each spot or a method of estimating the beam range for each group including multiple spots, thereby improving usability. EXAMPLES

[0073] A fifth embodiment will be described with reference to Fig. 10. In this embodiment, 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 controller 40A switches between the two particle beam generators 10(1) and 10(2) in a predetermined order to output the beams B1 and B2 from the irradiation device 25A. Note that signal lines are omitted as appropriate in FIG. 10 and FIG. 11, which will be described later.

[0075] The present embodiment thus configured also has the same operational effects as those of the embodiment 1. However, since the particle beam generator 10 of the embodiment 1 can output beams B1 and B2 having different properties from a single device, the introduction cost of the particle beam therapy system of the embodiment 1 is lower. EXAMPLES

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

[0077] The present embodiment thus configured also achieves the same effects as those of the embodiment 5. 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 embodiment 5.

[0078] The present invention is not limited to the above-described embodiment. A person skilled in the art can make various additions and modifications within the scope of the present invention. The above-described embodiment is not limited to the configuration example shown in the attached drawings. The configuration and processing method of the embodiment can be appropriately changed within the scope of achieving the object of the present invention.

[0079] In addition, each component of the present invention can be selected arbitrarily, and the invention having the selected configuration is also included in the present invention. Furthermore, the configurations 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 a particle beam 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 to be irradiated 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 for treating the irradiation target.

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

[0084] (Representation 4) The particle beam therapy system according to any one of Representations 1-3, 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) A particle beam therapy system according to any one of Representations 1-4, 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 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 according to any one of Representations 1-5, wherein the control device corrects information indicating an internal structure of the irradiation target based on the residual energy of the first particle beam.

[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 particle beam on the irradiation target, and irradiates the first particle beam and the second particle beam from the irradiation device 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, irradiates the first particle beam from the irradiation device in groups consisting of a predetermined plurality of irradiation areas among the plurality of set irradiation areas, and irradiates the second particle beam from the irradiation device to each of the predetermined plurality of irradiation areas included in the group.

[0089] (Representation 9) The 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 a particle beam, or to estimate the range information for each group consisting of a predetermined number of irradiation areas among the plurality of irradiation areas.

[0090] (Representation 10) A particle beam therapy system according to 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 an 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) The 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 for irradiating a particle beam and a control device for controlling the irradiation device, the control device causing the irradiation device to irradiate a plurality of different types of particle beams to an object to be irradiated at different timings. [Explanation of symbols]

[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 including an irradiation device that irradiates a particle beam and a control device that controls the irradiation device, The control device is a particle beam therapy system that causes the irradiation device to irradiate a plurality of particle beams of the same type but for different purposes at different timings to an irradiation target.

2. The 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 for treating the irradiation target. The particle beam therapy system according to claim 1 .

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

4. 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. The particle beam therapy system according to claim 3 .

5. 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 to irradiate the irradiation target based on the estimated range information. The particle beam therapy system according to claim 4 .

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

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

8. The control device includes: Setting a plurality of irradiation regions for irradiating the irradiation target with a particle beam; irradiating the first particle beam from the irradiation device in a group unit consisting of a predetermined number of irradiation regions among the plurality of set irradiation regions; The second particle beam is irradiated from the irradiation device to each of the predetermined plurality of irradiation regions included in the group. The particle beam therapy system according to claim 5 .

9. The control device includes: It is possible to select whether to estimate the range information for each of a plurality of irradiation regions set for irradiating the irradiation target with a particle beam, or to estimate the range information for each group consisting of a predetermined number of irradiation regions among the plurality of irradiation regions. The particle beam therapy system according to claim 5 .

10. 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. The particle beam therapy system according to claim 5 .

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

12. The apparatus further includes a first particle beam generating device that supplies the first particle beam to the irradiation device, and a second particle beam generating device that supplies the second particle beam to the irradiation device. The particle beam therapy system according to claim 5 .

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, comprising: The control device controls the irradiation device to irradiate a plurality of different types of particle beams at different timings to an irradiation target. A method for controlling a particle beam therapy system.

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