JP7258501B2 - Particle beam therapy system - Google Patents

Description

The present invention relates to a particle beam therapy system and its control method.

Particle beam therapy is a cancer treatment method that destroys cancer cells by irradiating charged particles accelerated by a particle beam accelerator to cancer-affected areas. A particle beam has the highest dose concentration near the end of its range. For this reason, there is a feature that a large amount of energy can be released from the cancer-affected area, and damage to healthy tissue can be reduced. On the other hand, since a large amount of energy is emitted in a limited small area, high beam precision is required.

A particle beam therapy system (particle beam therapy system) that enables particle beam therapy is composed of the following subsystems. Subsystems are, for example, an ion source, an injection device, a particle beam accelerator, a beam transport system, an irradiation device, a treatment table, an imaging device that assists treatment, treatment planning software, and a control device that controls each subsystem.

Accelerators are also miniaturized by using superconducting magnets, where synchrotrons or cyclotrons are used. The beam transport system includes a fixed beamline or a combination of a fixed beamline and a rotatable gantry. The gantry rotates about a predetermined axis of rotation (eg, an axis parallel to the patient's body axis). By rotating the irradiation device around the patient by means of the gantry, it is possible to irradiate the affected area with the particle beam bent by the magnet from any angle around the rotation axis. By irradiating the particle beam from multiple directions, it is possible to disperse the damage that the particle beam may cause to healthy tissue passing through until it reaches the cancer-affected area. Hereinafter, the particle beam may be abbreviated as beam.

Irradiation devices capable of scanning irradiation are known. An irradiation device capable of scanning irradiation (hereinafter also referred to as a scanning irradiation device) is equipped with two scanning electromagnets, and scans the beam so as to cover a surface perpendicular to the direction in which the beam travels. Scanning irradiators form a concentrated dose distribution on cancer lesions by scanning using beams that reach different depths. For this reason, in recent years, a particle beam therapy system having a rotatable gantry and a scanning irradiation device has become mainstream.

An example of scanning irradiation is a spot scanning irradiation method. In this irradiation method, the gantry rotates to an angle determined by the treatment plan and stops. Next, beams of planned doses are sequentially irradiated toward the spots corresponding to the angles. The gantry then rotates to the next angle and stops. The spot scanning irradiation method is also called a “Step and Shoot” method because “rotation→stop→irradiation” is repeated until irradiation of all spots at all angles determined in the treatment plan is completed.

WO2017/156419 Japanese Patent No. 4872540 Japanese Patent No. 5521225

Seco et al. , International Journal of Radiation Oncology Vol. 87, "Proton Arc Reduces Range Uncertainty Effects in SBRT for NSCLC Lung Cancer" Ding et al. , International Journal of Radiation Oncology Vol. 96, "Scanning Proton Arc Therapy"

Even with a particle beam therapy system having a 360-degree rotatable gantry, only two or three angles are used in actual treatment, and the function of the gantry is not fully utilized.

In the future, with the aim of improving the quality of life of patients, it is believed that cancer treatment that irradiates a large dose of beam in a short period of time will become widespread. For this purpose, there is a need for a particle beam therapy system that can irradiate the affected area with beams from more directions and increase the concentration of the dose.

However, because the gantry is heavy, when the gantry is stopped, the transport equipment and the irradiation equipment mounted on the gantry shake, and they have to stand still for several seconds until the shaking stops. Therefore, if the current "Step and Shoot" method is used to irradiate the beam while stopping at many angles, the treatment time increases.

Patent Document 1 includes a simple description of "substantially continuous rotating irradiation", but does not propose a method for realizing it.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide a particle beam therapy system and a control method thereof that enable efficient and appropriate irradiation of a particle beam.

In order to solve the above problems, a particle beam therapy system according to the present invention is a particle beam therapy system that irradiates a particle beam from an accelerator, comprising: an irradiation device that irradiates a predetermined position with a particle beam; A gantry that rotates around and a control device that controls the operation of the irradiation device and the gantry. A particle beam is emitted from a predetermined angle range set in advance.

According to the present invention, it is possible to irradiate a predetermined position with a particle beam from a predetermined angle range from the irradiation device while rotating the gantry.

1 is an explanatory diagram showing an overall outline of a particle beam therapy system; FIG. 1 is an overall configuration diagram of a particle beam therapy system; FIG. It is a block diagram of an irradiation apparatus. It is a hardware block diagram of a treatment planning apparatus. It is an explanatory view showing a control structure. FIG. 10 is a diagram showing a workflow for creating a treatment plan; FIG. 4 is an explanatory diagram showing spot management information; FIG. 4 is an explanatory diagram showing how a particle beam is scanned while rotating the gantry; 4 is a flow chart showing the whole particle beam irradiation. 4 is a flow chart showing irradiation start control. 4 is a flowchart showing irradiation stop control; FIG. 3 is an explanatory diagram showing a communication system between a gantry and a main controller; 10 is a flowchart showing irradiation stop control according to Example 5. FIG. 9 is a flowchart showing another example of irradiation stop control; A user interface screen for selecting either a method of irradiating a beam while continuously rotating the gantry (ARC mode) or a method of irradiating a beam by repeatedly rotating and stopping the gantry (IMPT mode) according to the sixth embodiment. It is an explanatory view showing .

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below based on the drawings. The particle beam therapy system according to this embodiment performs scanning irradiation while continuously rotating the gantry. This irradiation method can be called continuous rotating irradiation.

In the prior art, the target spot irradiated with the beam is only defined as two-dimensional coordinate values, and there is no consideration of the incident angle of the beam and the allowable range of the incident angle. Therefore, when the beam is emitted from the irradiation device while the gantry is continuously rotated, it may not be possible to irradiate the beam to a predetermined position.

Therefore, in this embodiment, the gantry is continuously rotated while the beam is emitted from the irradiation device, and an allowable angle range is set for each spot. When you enter, fire a beam from the irradiation device. That is, in this embodiment, instead of controlling the rotation of the gantry according to the position of the target spot, the beam is emitted at the moment the gantry reaches a predetermined angular range with respect to the target spot while continuously rotating the gantry. .

In this embodiment, beam irradiation to each spot is managed by spot management information T1, as will be described later with reference to FIG. The spot management information T1 stores spot position and beam information (hereinafter also referred to as position information) and a predetermined angle range regarding the irradiation angle of the beam in association with each spot.

The spot position and beam information include, for example, coordinates (x, y) [mm], beam energy E [MeV/n] or range Range [mm], and dose Q [MU]). The predetermined angular range includes, for example, the irradiation angle θ and the allowable angular range dθ.

The gantry rotates the irradiation device around the patient, and the angle of the gantry also determines the angle of the irradiation device. Therefore, in this embodiment, the angle of the irradiation device may be expressed as the angle of the gantry.

The control device of this embodiment acquires the gantry angle in real time, and controls continuous rotation irradiation based on, for example, the information indicating the state of the accelerator, the information indicating the state of the treatment table, and the angle of the gantry.

According to this embodiment, since the beam is emitted from the irradiation device while the gantry is continuously rotating, the treatment time can be shortened compared to the conventional "Step and Shoot" method. The treatment time of the particle beam therapy system of this embodiment can be shortened by (the number of beam irradiation directions)×(the time during which the beam cannot be irradiated due to rotation). Since the particle beam therapy system of this embodiment is a control system that irradiates beams corresponding to the angle conditions for each spot, it is possible to increase the number of beam irradiation directions from several tens to several hundred, thereby achieving dose concentration. can improve sexuality.

FIG. 1 is an explanatory diagram showing an overall overview of a particle beam therapy system 1 according to this embodiment. As shown in FIG. 1(1), in this embodiment, the gantry 13 (see FIG. 2) is continuously moved along the movement path TR. In this embodiment, moving along a circular or substantially circular trajectory may be referred to as continuous rotation.

Inside the gantry 13, a treatment table 15 is supported by an articulated robot arm 152 (both are shown in FIG. 3). The patient 4 is placed and fixed on the top board 151 (see FIG. 3) of the treatment table 15 .

When the gantry 13 continuously rotates along the trajectory TR, the position and orientation of the irradiation device 14 also continuously change along with this rotation. When the gantry angle (irradiation angle of the irradiation device) enters a predetermined angular range, the particle beam is irradiated toward the affected area 41 of the patient 4 .

When the irradiation angle (gantry angle) deviates from a predetermined angle range or when a beam having a predetermined energy cannot be produced, beam scanning irradiation is stopped. The gantry 13 continues to rotate without stopping during beam irradiation and even while irradiation is stopped. Then, when the angle of the gantry enters a predetermined angle range for the next irradiation candidate spot, the irradiation device 14 emits a beam. As described above, in this embodiment, while the gantry 13 is continuously rotated, the spot is irradiated with the beam every time the angle of the irradiation device enters the predetermined angle range set for each spot.

FIG. 1(2) shows the functional configuration of the main controller 21 (see FIG. 2) that controls the entire particle beam therapy system 1. As shown in FIG. Details of the operation of the main controller 21 will be described later with reference to FIG. 6 and the like. The main controller 21 includes, for example, a treatment plan acquisition unit F11, a patient state acquisition unit F12, a spot information generation unit F13, an irradiation control unit F14, an accelerator state acquisition unit F15, a gantry angle acquisition unit F16, a treatment table state acquisition unit F17, an irradiation A state acquisition unit F18 is provided.

The treatment plan acquisition unit F11 has a function of acquiring a treatment plan created by a doctor. The patient condition acquisition unit F12 has a function of acquiring the condition of the affected part 41 measured by, for example, a CT (Computed Tomography) device or the like. The spot information generation unit F13 has a function of setting at least one spot (usually a plurality of spots) based on the treatment plan and the condition of the affected area, and generating information of each spot. The generated spot position information and the like and the predetermined angle range are stored in the spot management information T1 (see FIG. 7).

The irradiation control unit F14 has a function of controlling beam irradiation by the irradiation device 14 . The irradiation control unit F14 performs beam irradiation based on the information obtained from the accelerator state obtaining unit F15, the gantry angle obtaining unit F16, and the treatment table state obtaining unit F17, and the irradiation results obtained by the irradiation state obtaining unit F18. and control stopping.

The accelerator state acquisition unit F15 has a function of acquiring information indicating whether or not a beam having a predetermined energy can be extracted from the accelerator 12 . The gantry angle acquisition unit F<b>16 has a function of acquiring the angle of the gantry 13 . The angle of the gantry 13 can be detected by a rotation angle sensor (not shown). If the gantry 13 moves at a constant speed, the angle can also be calculated based on the elapsed time.

The treatment table state acquisition unit F17 is a function of acquiring the state of the treatment table 15 . The state of the treatment table 15 is, for example, the position and posture of the treatment table 15 . The irradiation state acquisition unit F18 has a function of monitoring the dose with which the affected part 41 is irradiated. When the planned dose to the affected area 41 is achieved, the irradiation control unit F14 stops beam irradiation.

FIG. 1(3) is a graph showing the relationship between the movement (continuous rotation) of the gantry 13 and the state of beam irradiation by the irradiation device. The upper part of FIG. 1(3) shows the speed change of the gantry 13 . The lower side of FIG. 1(3) shows the on/off state of beam irradiation.

It is assumed that the gantry 13 starts moving from the initial position (speed=0) and rotates continuously at a constant speed from time t1 to time t4. A beam irradiation period ARC1 for the first spot is from time t1 to time t2. That is, the gantry angle is within the predetermined angle range of the first spot from time t1 to time t2. In the first beam irradiation period ARC1, scanning irradiation is performed toward the affected area 41 with a plurality of beams from the irradiation device 14 whose angle changes every moment.

After time t2, the beam irradiation is stopped because the angle of the gantry 13 deviates from the predetermined angle range of the first spot. The gantry 13 continues to rotate and enters the predetermined angle range for the second spot at time t3. The period from time t3 to time t4 is the second beam irradiation period ARC2 in which the second spot is irradiated with the beam. In the second beam irradiation period ARC2 as well, a plurality of beams are scanned and irradiated toward the affected area 41 from the irradiation device 14 whose angle changes from moment to moment.

According to this embodiment configured in this manner, the beam can be scanned and irradiated from the irradiation device 14 toward the affected area 41 while the gantry 13 is continuously rotated. According to this embodiment, when the angle of the gantry 13 falls within the predetermined angle range of any spot, the beam is emitted from the irradiation device 14 toward the spot within the predetermined angle range. As a result, according to the particle beam therapy system 1 according to the present embodiment, it is possible to irradiate the affected area 41 with more beams than in the conventional system, thereby improving the efficiency of treatment and improving the patient's quality of life. be able to.

A first embodiment will be described with reference to FIGS. 2 to 11. FIG. FIG. 2 shows the overall configuration of the particle beam therapy system 1. As shown in FIG. The particle beam therapy system 1 includes, for example, an ion source and injection device 11, a particle beam accelerator 12, a rotatable gantry 13, an irradiation device 14, a treatment table 15, and a control system 20. .

Charged particles generated by the ion source are guided to the particle beam accelerator 12 by an injector. Although FIG. 2 shows a system using a pre-accelerator and a synchrotron, a cyclotron or synchrocyclotron may be used, or a particle beam accelerator using a superconducting electromagnet may be used.

The charged particle beam 3 accelerated within the accelerator 12 is transported to the treatment room via the beam transport system and the gantry 13 . A charged particle beam 3 is emitted from an irradiation device 14 supported by a gantry 13 toward a patient 4 on a treatment table 15 . A charged particle beam may be abbreviated as a particle beam or beam. Also, since the number of appearances of beams is large, the code "3" may be omitted.

A configuration example of the control system 20 that controls the particle beam therapy system 1 will be described. Control system 20 includes, for example, main controller 21 , treatment planning device 22 , auxiliary imaging equipment controller 23 , and memory device 24 . A detailed configuration example will be described later with reference to FIG.

FIG. 3 shows the configuration of the irradiation device 14 and the state of beam irradiation.

In order to irradiate the beam 3 to a certain spot 42 of the diseased part 41, the irradiation device 14 shown in FIG. 3 is used. The energy of the beam 3 is selected to reach the spot 42 (target) to be irradiated. A range shifter 146 may be used to adjust the beam energy to the depth of the spot 42 .

Here the beam loses a lot of energy at small depth regions, ie has a narrow Bragg peak. Broadening of the Bragg peak may be necessary to form a uniform dose distribution. A ridge filter 145 is used for that purpose.

The coordinates (x, y) of the spot 42 are defined in a plane perpendicular to the direction of travel of the beam. By supplying currents corresponding to the two-dimensional coordinate values to the two scanning electromagnets 141 and 142 , the beam is bent so as to reach the spot 42 . The dose and position of the beam are measured by dose monitor 143 and position monitor 144 . After the beam of the predetermined dose determined by the treatment plan is irradiated to the correct position, the next spot is irradiated.

FIG. 4 shows a configuration example of the treatment planning device 22. As shown in FIG. The treatment planning device 22 is configured as a computer system having, for example, a microprocessor (CPU: Central Processing Unit in the figure) 221 , a memory 222 , a storage device 223 , a communication interface device 224 and a user interface device 225 .

The storage device 223 comprises, for example, a flash memory device, hard disk drive, etc., and stores computer programs such as an operating system 2231 and a treatment planning program 2232 . In addition to these computer programs 2231 and 2232, software (not shown) such as driver software is also stored in the storage device 223. FIG.

The function of the treatment planning apparatus 22 is realized by the microprocessor 221 reading the treatment planning program 2232 stored in the storage device 223 into the memory 222 and executing it.

A communication interface device 224 is a device for communicating with the main controller 21 . The user interface device 225 is a device for exchanging information with a user (physician) who uses the treatment planning device 22 . User interface device 225 includes an information output device and an information input device. Examples of information output devices include displays, printers, voice synthesizers, and the like. Examples of information input devices include keyboards, pointing devices, touch panel voice recognition devices, and the like. For example, the calculation results of the treatment plan and the operation to the program 2232 are shown on the display.

The treatment planning program 2232 calculates optimum spot management information T1 for the patient 4 and the affected area 41. FIG. The treatment planning program 2232 runs on the operating system 2231 and has access to the required memory 222 and microprocessor 221 . The treatment planning program 2232 can also access the storage device 223 using the user interface device 225 to enter patient information and save calculation results.

A workflow for creating a treatment plan is described below in FIG. Here, an outline of the treatment planning software 2232 will be described first. By using the treatment planning software 2232, the doctor determines several beam angles to irradiate the affected area 41. FIG. The treatment planning program 2232 is created so as to optimize the information for each spot irradiated with the beam based on each irradiation angle determined by the doctor.

FIG. 5 shows the overall configuration of the control system 20. As shown in FIG. In this embodiment, the main controller 21 plays a central role in irradiation control. The main controller 21 is connected to, for example, a treatment planning device 22, an auxiliary imaging equipment control device 23, a storage device 24, an acceleration system control device 25, a gantry control device 26, an irradiation control device 27, and a treatment couch control device .

The auxiliary imaging equipment control device 23 is, for example, a CT device or the like. Auxiliary imaging equipment controller 23 may be configured as a device that tracks moving lesion 41 . For example, the auxiliary imaging equipment controller 23 can track the movement of a gold marker implanted near the affected area 41 with a fluoroscope.

The storage device 24 is a device for storing history data (data indicating progress) of particle beam therapy.

An acceleration system controller 25 controls the accelerator 12 and the beam transport system. The acceleration system controller 25 controls an accelerator controller 251 that controls the accelerator 12 and a transport system controller 252 that controls the beam transport system.

A gantry controller 26 controls the gantry 13 . The irradiation control device 27 controls the irradiation device 14 . The irradiation control device 27 controls a scanning magnet control device 271, a dose monitor control device 272, a position monitor control device 273, a ridge filter control device 274, and a range shifter control device 275, respectively. A scanning magnet control device 271 controls the scanning electromagnets 141 and 142 . The dose monitor controller 272 controls the dose monitor 143 . Position monitor controller 273 controls position monitor 144 . Ridge filter controller 274 controls ridge filter 145 . Range shifter controller 275 controls range shifter 146 .

The treatment table control device 28 controls the position, attitude, etc. of the treatment table 15 .

The main controller 21 of the control system 20 reads the treatment plan from the treatment planning device 22, and instructs the controllers 23, 25, 26, 27, 28 of each subsystem based on the treatment plan, so that the accelerator 12, the beam It controls the transportation system, the gantry 13, the irradiation device 14, the treatment table 15, and the like.

The main controller 21 can store the progress of beam irradiation to the affected area 41 in the storage device 24 . When resuming treatment, the main controller 21 can read the progress of the previous treatment from the storage device 24 and use it.

FIG. 6 is a flow chart of treatment plan creation processing. The treatment planning device 22 reads a CT image of the patient 4 to be irradiated (S11), and receives an instruction (prescription) from the doctor via the user interface device 225 (S12). A doctor's prescription includes, for example, information such as which affected areas to receive and how much to irradiate with the beam, and which vital organs should be protected from the beam.

The treatment planning device 22 sets each spot to be irradiated with the beam and the beam irradiation direction to each spot (S13). The treatment planning device 22 optimizes the irradiation dose to each spot (S14). After the irradiation angle and irradiation dose for each spot are determined, the treatment planning system 22 calculates the dose distribution within the patient's body (S15).

The treatment planning device 22 displays the result of creating the treatment plan through the user interface device 225 (S16), and stores the created treatment plan in the storage device 24 (S17). In addition, the treatment planning system 22 sends the information required by the controllers 23, 25, 26, 27, 28 of the other subsystems.

FIG. 7 shows a configuration example of the spot management information T1. The spot management information T1 is information generated by the treatment planning device 22 for each spot. The spot management information T1 includes spot position and beam information (C11 to C13) and a predetermined angle range (C14, C15).

The coordinate information C11 specifies the spot position as two-dimensional coordinates (x, y) on the plane on which the beam is incident. The beam information C12 indicates the beam energy or range corresponding to the spot position (depth). The dose/number of particles/beam current information C13 indicates the dose of the beam. The irradiation angle information C14 indicates the reference value (θ) of the beam angle with which the spot is irradiated. The permissible angle range information C15 indicates the permissible range of beam irradiation angles. The beam hits the spot at an acceptable angle. Beam irradiation is stopped when it deviates from the allowable range.

The allowable angle can be set as a range from plus dθ to minus dθ with respect to the reference angle (θ). It is also possible to change the value of the allowable angle between the front side and the rear side of the irradiation device 14 in the traveling direction.

FIG. 8 shows the state of continuous rotating irradiation according to this embodiment. A method of controlling the particle beam therapy system 1 that realizes continuous rotational irradiation will be described later with reference to FIG.

It is assumed that the irradiation device 14 moves from left to right in FIG. A plurality of spots 42 are set on an affected area 41 such as a tumor in the treatment plan. When the angle of the irradiation device 14 (the rotation angle of the gantry 13) enters the angle range (θ, dθ) of each spot 42, the spot is irradiated with the beam.

FIG. 9 is a flowchart showing the entire particle beam irradiation process. First, the main controller 21 reads a treatment plan from the treatment planning device 22 (S21). When resuming the continuation of the previous treatment, the main controller 21 reads the previous progress status from the storage device 24 (S21).

When the gantry 13 begins to rotate stably, the main controller 21 receives information indicating the angles of the gantry 13 (for example, θg1, θg2, θg3, . . . ) from the gantry controller 26 (S22). Here, the gantry control device 26 transmits the angle of the gantry 13 to the main controller 21 as numerical information. The method of transmitting the numerical value of the angle as it is is called "Data type" in this specification. FIG. 12(1) shows an example of "Data type". As described above, the gantry 13 supports and moves the irradiation device 14 , so the angle of the gantry 13 indicates the angle of the irradiation device 14 .

The main controller 21 receives the angle (for example, θg1) and information from other subsystems 25, 27, 28 (S22), and determines whether the beam is being irradiated based on the received information ( S23).

When the main controller 21 determines that beam irradiation is not being performed (S23: NO), it determines spot candidates to be irradiated by referring to the treatment plan and spot management information T1 (S24). The main controller 21 causes the acceleration system controller 25 to prepare a beam corresponding to the determined depth of the spot candidate (S25). For example, the main controller 21 instructs the acceleration system controller 25 to switch the beam energy. Alternatively, the main controller 21 instructs the irradiation control device 27 to adjust the range shifter 146 . The main controller 21 may instruct both the acceleration system controller 25 and the irradiation controller 27 .

The main controller 21 determines whether to start irradiation based on the information from the controllers 25 to 28 of each subsystem (S26). Details of step S26 for determining the start of irradiation will be described later with reference to FIG.

When determining to start beam irradiation (S26: YES), the main controller 21 instructs the irradiation control device 27 to start irradiation (S27). Upon receiving the irradiation start signal from the main controller 21, the irradiation control device 27 causes the irradiation device 14 to irradiate the target spot with a beam. When the irradiation cannot be started (S26: NO), the main controller 21 returns to step S22.

The main controller 21 causes the storage device 24 to store the history of beam irradiation as progress (S30).

On the other hand, when the main controller 21 determines in step S23 that the beam irradiation is not being performed (S23: YES), it determines whether or not the beam irradiation currently being performed should be stopped based on the information of each of the controllers 25 to 28 ( S28). The details of step S28 for determining whether to stop irradiation will be described later with reference to FIGS. 11 to 13. FIG.

When the main controller 21 determines that beam irradiation should be stopped (S28: YES), it instructs the irradiation control device 27 to stop (S29). Upon receiving a stop signal from the main controller 21 , the irradiation control device 27 causes the irradiation device 14 to stop beam irradiation. Then, the main controller 21 saves the history of beam irradiation as progress in the storage device 24 (S30). If the main controller 21 does not stop the irradiation (S28: NO), the process returns to step S22.

FIG. 10 is a flowchart showing the irradiation start determination process described in step S26 in FIG. An example will be described below in which a target spot (Spot1) positioned at coordinates (x1, y1) is irradiated with a beam having energy E1 from a predetermined angular range (θ1, dθ1).

As described above, the main controller 21 acquires information from each of the controllers 25 to 28 (S41), and determines spot candidates to be irradiated (hereinafter also referred to as target spots) based on the treatment plan and spot management information T1. (S42). Then, the main controller 21 instructs the acceleration system controller 25 to prepare a beam having the energy (E1) set for the target spot (Spot1) (S43).

For example, if the gantry angle θg1 is within the predetermined angle range (θ1−dθ1, θ1+dθ1) (S44: YES AND S45: YES), and the beam energy to be applied to the target spot (Spot1) can be accelerated to the energy E1, If there is (S46: YES), the irradiation conditions are satisfied. Therefore, the main controller 21 determines that Spot1 (x1, y1, E1, Q1, θ1, dθ1) may be irradiated with the beam, and instructs the irradiation control device 27 to start irradiation (S47).

Specifically, the main controller 21 returns to step S41 and waits until the gantry angle reaches the predetermined angle range (θ1−dθ1≦θg1) (S44: NO). Then, when the gantry angle deviates from the predetermined angle range (θg1≦θ1+dθ1), the main controller 21 stops beam irradiation (S56).

When the irradiation control device 27 receives an irradiation start signal from the main controller 21 (S48), the scanning electromagnets 141 and 142 are driven by supplying current or voltage corresponding to the two-dimensional coordinate values (x1, y1) of the target spot. (S49). Further, the irradiation control device 27 instructs the acceleration system control device 25 to output a beam having energy E1 (S50). The irradiation control device 27 may directly instruct the acceleration system control device 25 via a communication line (not shown), or may instruct the acceleration system control device 25 via the main controller 21 .

The irradiation control device 27 monitors signals from the dose monitor 143 and the position monitor 144 (S51, S53), and when the stop condition is satisfied, instructs the acceleration system control device 25 to stop beam output (S52, S54). ).

That is, when the irradiation position of the beam shifts (S51: YES), or when the dose Q1 irradiated to the target spot reaches a predetermined dose Qt (S53: YES), the accelerator 12 is stopped (S52, S54). The irradiation control device 27 reports to the main controller 21 that the beam irradiation to the target spot has been completed and the irradiated dose (S55).

Upon receiving the report from the irradiation control device 27, the main controller 21 confirms the end of the irradiation of the target spot (S56), and saves the progress in the storage device 24 (S57). Then, the main controller 21 determines whether there is a spot candidate for the next irradiation target (S58), and if it determines that there is a spot candidate for the next irradiation target (S58: YES), the process returns to step S42. If there is no spot candidate to be irradiated next (S58: NO), the main controller 21 saves the irradiation progress in the storage device 24 (S59).

FIG. 11 is a flowchart of processing for ending or stopping beam irradiation. The main controller 21 receives information from the control devices 25 to 28 of each subsystem to monitor whether or not a predetermined stop condition is established (S62, S64, S66).

For example, when the amount of irradiation to the target spot is achieved (S62: YES), the main controller 21 normally terminates beam irradiation (S63). When the gantry angle deviates from the predetermined angle range of the target spot (S64: YES), the main controller 21 stops beam irradiation (S65). The main controller 21 also stops the beam irradiation (S67) when the beam having the predetermined energy cannot be extracted from the accelerator 12 (S66: YES).

When the main controller 21 decides to end or stop beam irradiation, it transmits a stop signal to the irradiation control device 27 (S68). Then, the main controller 21 determines the next spot candidate to be irradiated (S69), and saves the progress in the storage device 24 (S70).

For example, when a synchrotron is used as the particle beam accelerator 12, the main controller 21 decides to stop beam irradiation when there is no accumulated charge or the gantry angle exceeds the allowable range. In either case, the main controller 21 immediately transmits a stop signal to the irradiation control device 27 .

When the irradiation is stopped because the beam cannot be emitted from the accelerator 12, the main controller 21 requests the acceleration system controller 25 to perform control to replenish the charge. When the gantry angle exceeds the predetermined angle range and when the irradiation ends normally, the main controller 21 saves the irradiation progress in the storage device 24 and selects the next spot candidate to be irradiated.

Here, steps S62 and S64 are preferably performed before step S66. The reason is to suppress excessive beam irradiation. The accuracy of the control can be ensured by executing the stop condition determinations S62, S64, and S66 in order rather than in parallel.

When the progress of irradiation is stored in the storage device 24, the dose applied to each spot is recorded. Instead of spots, for example, the progress may be stored in terms of beam irradiation directions and layers (Layer, which means a layer composed of spots irradiated with beams of the same energy). The save format of the progress is not specified.

Ideally, the irradiation of all spots is completed while the gantry 13 makes one rotation from 0 degrees to 360 degrees. However, as described with reference to FIG. 10, there may be cases where irradiation must be stopped before the administration of the prescribed prescribed dose is completed (S62, S64, S66). In that case, the main controller 21 can read the progress saved during the previous treatment from the storage device 24 and continue the treatment when the irradiation can be resumed.

When resuming an interrupted treatment, the gantry 13 can be rotated in a direction opposite to the previous rotation direction. It is necessary to reverse the sign of the setting value ((θ-dθ-), (θ+dθ+), etc.). However, the case where (-dθ-) and (+dθ) are the same value is excluded. The direction of rotation is also considered when selecting the next spot candidate.

According to this embodiment configured as described above, the beam can be scanned and irradiated from the irradiation device 14 toward the affected area 41 while the gantry 13 is continuously rotated. As a result, according to this embodiment, the affected area 41 can be efficiently irradiated with the beam, the efficiency of treatment can be increased, and the patient's quality of life can be improved.

Example 2 will be described with reference to FIG. Each of the following embodiments, including the present embodiment, corresponds to a modified example of the first embodiment, so the differences from the first embodiment will be mainly described.

The gantry control device 26 of this embodiment sends an electrical signal of one pulse to the main controller 21 each time the gantry 13 reaches a certain angle, instead of sending the angle information of the gantry 13 to the main controller 21 .

As shown in FIG. 12(2), when the gantry 13 rotates at a constant speed, the electrical pulse is sent like a clock signal, so this method is called "clock type". When the angular intervals for data transmission are small, there is an advantage that transmission and reception can be performed at high speed compared to the "Data type" shown in FIG. 12(1) described in the first embodiment.

Example 3 will be described with reference to FIG. The gantry control device 26 of this embodiment preliminarily reads information (θ and dθ) on a predetermined angle range for each spot, and transmits a gate signal while the gantry 13 passes through the range of angles that may be irradiated.

As shown in FIG. 12(3), this gate signal rises when the gantry 13 reaches the angle (θ−dθ) that is the starting point of the predetermined angle range, and the gantry 13 reaches the angle (θ−dθ) that is the end point of the predetermined angle range. .theta.+d.theta.) is formed as a long digital pulse that falls off. This system is called "Gate type".

In "Gate type", the gantry control device 26 sends a gate signal to the acceleration system control device 25 and the irradiation control device 27 without going through the main controller 21 in order to determine whether the gantry control device 26 can irradiate the beam. Sendable.

Furthermore, "Gate type" can be realized by a logic circuit instead of a computer. For example, for a cyclotron accelerator 12 that generates a continuous beam, the gating signal can be used directly for controlling the accelerator system by using it as a beam ejection signal.

Additionally, the auxiliary imaging equipment controller 23 may also output a gating signal as a cue for illumination. In this case, the gate signal of the auxiliary imaging equipment control unit 23 and the gate signal of the gantry control unit 26 are input to the logic circuit, and the AND (coincidence) of both signals is obtained to generate a beam irradiation signal (beam ON signal). can be generated. Thus, in this embodiment, the control speed can be improved by using the "Gate Type" signal and utilizing the logic circuit.

In order to ensure the accuracy of the "Clock type" shown in FIG. 12(1) and the "Gate type" control shown in FIG. 12(3), it should be combined with the "Data type" after considering the control speed. is also conceivable. That is, it is possible to improve the accuracy of irradiation control by using both acquisition of the gantry angle as numerical information and a gate signal indicating that the gantry 13 has entered a predetermined angle range.

Example 4 will be described. As described in Example 3, not all control needs to go through the main controller 21 . Signals may be exchanged directly between the subsystem controllers 23-28.

Since the gantry 13 rotates continuously during beam irradiation, it is desirable that the processing speed of the control system is as fast as possible. Therefore, a control system that allows direct communication between the gantry control device 26, the irradiation control device 27, and the acceleration system control device 25 is conceivable.

For example, a clock signal or gate signal of the gantry controller 26 is processed by a logic circuit to generate a beam extraction signal or a beam on/off signal, and the generated signal is provided to the acceleration system controller 25 or the irradiation controller 27. can be considered.

Furthermore, for example, a control system that allows direct communication between the irradiation control device 27 and the acceleration system control device 25 may be used in order to quickly perform on/off control of the beam.

The present embodiment configured in this way also has the same effect as the first embodiment. Furthermore, in this embodiment, irradiation control can be executed at high speed.

Embodiment 5 will be described with reference to FIGS. 13 and 14. FIG. In Example 5, the termination of irradiation is determined in parallel for each termination condition. That is, in this embodiment, the center determination process of FIG. 13 and the cancellation determination process of FIG. 14 are executed in parallel, and beam irradiation is stopped when cancellation is determined in either process.

FIG. 13 shows processing for stopping beam irradiation when the angle of the gantry 13 deviates from the predetermined angle range.

The main controller 21 acquires the gantry angle and information on the accelerator 12 (S81), and determines whether the gantry 13 angle is out of the predetermined angle range of the target spot (S82). When the main controller 21 determines that the angle of the gantry 13 is out of the predetermined angle range (S82: YES), it decides to stop beam irradiation (S83), and saves the progress up to that point in the storage device 24. (S84). If NO in step S82, the process returns to step S81.

FIG. 14 shows a process of stopping beam irradiation when a beam with a predetermined energy cannot be extracted from the accelerator 12. FIG.

The main controller 21 acquires the angle of the gantry 13 and the information of the accelerator 12 (S91), and determines whether beam extraction is impossible (S92). If the beam cannot be extracted from the accelerator 12 (S92: YES), the main controller 21 determines to stop beam irradiation (S93), and saves the progress up to that point in the storage device 24 (S94).

The main controller 21 can also instruct the acceleration system controller 25 to generate a beam. Note that if NO is determined in step S92, the process returns to step S91.

The present embodiment configured in this way also has the same effect as the first embodiment. Furthermore, in the present embodiment, beam irradiation can be stopped earlier than in the first embodiment, so excessive beam irradiation can be suppressed (in the case of FIG. 13).

Example 6 will be described. The particle beam therapy system 1 of this embodiment can perform not only the continuous rotation irradiation method that is characteristic of this embodiment, but also conventional irradiation methods (eg, Intensity Modulated Particle Therapy). Here, the continuous irradiation method according to this embodiment is called ARC mode, and the conventional method is called IMPT mode.

If the ARC mode and the IMPT mode can be switched depending on the patient's case, more appropriate treatment can be performed. The particle beam therapy system 1 of this embodiment provides the doctor with a screen as shown in FIG. 15(1). This screen presents the physician with a choice between IMPT and ARC modes.

As shown in FIG. 15(2), when the ARC mode is selected, the doctor designates the continuous rotation irradiation section by the angle of the gantry 13 . Alternatively, as shown in FIG. 15(3), it is also possible to designate continuous rotational irradiation to be performed in a plurality of discontinuous periods. In this case, a period in which beam irradiation is not performed is provided between a period in which continuous rotational irradiation is performed and a period in which the next continuous rotational irradiation is performed.

The present embodiment configured in this way also has the same effect as the first embodiment. Furthermore, according to this embodiment, the IMPT method and the ARC method can be combined, so appropriate beam irradiation can be performed according to the patient's case. Furthermore, according to this embodiment, a plurality of continuous rotation irradiation periods can be set during one rotation of the gantry 13, so that the possibility of beam irradiation to important organs other than the affected part 41 is further reduced. It can improve safety and usability.

Example 7 will be described. In this embodiment, the accelerator 12 is caused to generate and prepare a beam during periods when beam irradiation is not performed.

In the irradiation plan optimized by the treatment planning device 22, the beam irradiation angles are not necessarily continuous and uniformly distributed. Depending on the shape of the affected area 41, the density of other tissues located around it, the position of important organs, and the like, there may be a period during which no irradiation is performed or an angular range with few target spots.

In that case, after the irradiation of a certain spot is completed, there is a gap time during which the gantry 13 does not reach the irradiation position of the next target spot. The main controller 21 approximates the length of the gap time, and when the gap time is longer than a predetermined value, the particle beam accelerator 12 that emits a discontinuous beam, such as a synchrotron accelerator, stores charge instructed to replenish This instruction is issued from the main controller 21 through the acceleration control device 25 .

This embodiment, which is configured in this way, also has the same effect as the first embodiment. Furthermore, according to the present embodiment, charges can be accumulated in the accelerator 12 using the gap time during which beam irradiation is not performed, so the possibility of stopping irradiation due to failure to extract the beam can be reduced. , the treatment time can be shortened.

Example 8 will be described. In Example 1 and the like, the angular range in which each spot can be irradiated with a beam is set in advance, and beam irradiation is controlled according to the angle of the gantry 13 . If the gantry 13 rotates at a constant speed, time can be used instead of angle. Here, if the angle of the gantry 13 is θ, the rotation time is t, and the angle (angular velocity) of rotation per unit time is ω, then θ=ω×t. From this equation, it can be seen that t and θ have the same information if the angular velocity is constant.

The present embodiment configured in this way also has the same effect as the first embodiment. Furthermore, in this embodiment, if the rotation start timing and angle (angular velocity) are known, the gantry angle can be calculated using only the internal clock without communication with the main controller 21 . Therefore, the operation of the control system 20 can be further speeded up.

In addition, this invention is not limited to embodiment mentioned above. Those skilled in the art can make various additions, modifications, etc. within the scope of the present invention. The above-described embodiments are not limited to the configuration examples illustrated in the accompanying drawings. The configuration and processing method of the embodiment can be changed as appropriate within the scope of achieving the object of the present invention.

In addition, each component of the present invention can be selected arbitrarily, and the present invention includes an invention having a selected configuration. Furthermore, the configurations described in the claims can be combined in addition to the combinations specified in the claims.

1: Particle beam therapy system, 11: Ion source and injection device, 12: Accelerator, 13: Gantry, 14: Irradiation device, 15: Treatment table, 20: Control system, 21: Main controller, 22: Treatment planning device, 24 : storage device, 25: acceleration system control device, 26: gantry control device, 27: irradiation control device, 28: treatment table control device

Claims (9)

A particle beam therapy device that irradiates a particle beam from an accelerator,
an irradiation device for irradiating a predetermined position with a particle beam;
a gantry that rotates the irradiation device around a treatment table;
a control device that controls the operation of the irradiation device and the gantry,
The control device is
while continuously rotating the irradiation device at a constant speed by the gantry, the irradiation device irradiates the predetermined position with a particle beam from a predetermined angular range;
Acquiring gantry angle information during rotation of the gantry, controlling irradiation of the particle beam by the irradiation device based on the acquired gantry angle information,
Spot management information that defines each spot to be irradiated is held, and the spot management information includes at least spot position information and the predetermined angular range within which the particle beam can be irradiated onto the spot. include,
Particle therapy equipment. The predetermined angle range includes a reference irradiation angle and a permissible angle range,
The particle beam therapy system according to claim 1. The control device causes the accelerator to generate a particle beam having a predetermined energy and waits before the value indicated by the gantry angle information enters the predetermined angle range.
The particle beam therapy system according to claim 1 . The controller stops irradiating the target spot with the particle beam when the particle beam from the irradiator deviates from the predetermined angular range.
The particle beam therapy system according to claim 1 . The controller stops irradiating the target spot with the particle beam when irradiation of a predetermined dose set in advance is achieved.
The particle beam therapy system according to claim 1 . The controller stops irradiating the target spot with the particle beam when the accelerator is unable to generate a particle beam with a predetermined energy.
The particle beam therapy system according to claim 1 . When stopping irradiation of the target spot with the particle beam, the control device selects the next target spot from among the spots stored in the spot management information.
A particle beam therapy system according to any one of claims 4 to 6 . The control device saves the progress of irradiation in a storage device when stopping the irradiation of the target spot with the particle beam.
The particle beam therapy system according to claim 7 . The control device restarts irradiation of the particle beam by the irradiation device based on the progress saved in the storage device.
The particle beam therapy system according to claim 8 .

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