Charged particle beam irradiation system

Abstract

To provide a charged particle beam irradiation system that can realize respiratory-gated irradiation using X-rays.SOLUTION: A charged particle beam irradiation system comprises a charged particle beam irradiation device for emitting charged particle beams transported from an accelerator, toward an isocenter. X-rays generated from a first X-ray generation part and a second X-ray generation part pass through the isocenter, and are detected by a first detection part and a second detection part. The first X-ray generation part and the second X-ray generation part are arranged so as to sandwich a virtual plane formed by orbits of the charged particle beams capable of being selected by the charged particle beam irradiation device. When a side on which the charged particle beams are incident on the charged particle beam irradiation device is defined as an upstream side, and a side on which the charged particle beams are emitted from the charged particle beam irradiation device is defined as a downstream side, the first detection part and the second detection part are located upstream or downstream from the first X-ray generation part and the second X-ray generation part.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a charged particle beam irradiation system. [Background technology]

[0002] Conventionally, particle beam therapy (sometimes referred to as proton beam therapy) has been used as a cancer treatment method, in which a charged particle beam, such as a proton beam or a heavy particle beam (e.g., a carbon beam), is irradiated to an affected area to treat the area. In such particle beam therapy, the dose of the charged particle beam is increased by irradiating the affected area from various directions while concentrating the charged particle beam on the affected area and suppressing exposure to areas other than the affected area. Patent Documents 1 and 2 disclose a device for irradiating a charged particle beam, in which a beam transport system and an irradiation unit are configured to rotate around the patient so that the patient can be irradiated with the charged particle beam from all directions. However, such a rotating irradiation device (hereinafter referred to as a rotating gantry) is large because it is configured to rotate around the patient. Therefore, Patent Document 3 discloses a device for irradiating a charged particle beam, in which the charged particle beam can be irradiated from any angle without using a rotating irradiation device. By not using a mechanism for rotating the irradiation unit, which is one of the reasons for the device's large size, the charged particle beam irradiation device described in Patent Document 3 is able to be made smaller than those described in Patent Documents 1 and 2. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6523076 [Patent Document 2] Patent No. 6158334 [Patent Document 3] Patent No. 6387476 Summary of the Invention [Problem to be solved by the invention]

[0004] Charged particle beams must be precisely irradiated onto the patient's treatment site. However, because the patient's organs constantly move due to factors such as breathing and pulsation, the treatment site constantly shifts relative to the charged particle beam's irradiation position. To address this issue, a treatment technique called respiratory-gated irradiation is used to perform treatment while taking into account the patient's breathing. One example of this irradiation technique is to monitor the condition of the tumor, markers placed around it, and the patient's internal organs using X-rays during treatment irradiation to confirm the treatment site for the charged particle beam irradiation position, and then control the charged particle beam irradiation at the appropriate timing. The X-ray generator and detector used for monitoring must be installed in suitable locations to enable high-precision detection. However, in the case of rotating gantries such as those described in Patent Documents 1 and 2, installation space is often limited, necessitating installation in specific locations. For example, by arranging the X-ray generator and detector facing each other so that they rotate coaxially with the charged particle beam irradiation system and do not obstruct the charged particle beam irradiation, the condition of the patient's internal organs can be detected and the charged particle beam can be irradiated. When using a rotating gantry with a rotation angle of 360 degrees or more (hereinafter referred to as a full gantry) as disclosed in Patent Document 1, the plane formed by the irradiation axes of each charged particle beam generated when irradiated from different angles and the plane formed by the axis connecting the X-ray generator and detector are generally configured to be on the same plane. That is, the X-ray generator and detector also rotate as the irradiation unit rotates. On the other hand, in the case of a rotating gantry with a rotation angle of less than 360 degrees (e.g., 180 degrees) as disclosed in Patent Document 2 (hereinafter referred to as a half gantry), the X-ray generator and detector may be installed without rotating simultaneously with the irradiation unit, unlike a full gantry. Non-rotation improves the installation accuracy of the X-ray generator and detector, and the repeatability of the positioning of the X-ray generator and detector after rotation. In contrast, in the case of a charged particle beam irradiation device other than a rotating gantry such as that described in Patent Document 3, it is difficult to arrange the plane formed by the irradiation axis of the charged particle beam and the plane formed by the axis connecting the X-ray generation unit and the detection unit on the same plane.For example, if the equipment is positioned so that the X-rays and proton beams travel along a cross section perpendicular to the patient's head-to-tail direction, there is a possibility that the irradiation nozzle will interfere with the FPD (Flat Panel Detector), which is the detection unit, or that the X-ray generator on the floor will interfere with the irradiation device, making it difficult to achieve.

[0005] Therefore, the present invention has been made in consideration of the above problems, and aims to provide a charged particle beam irradiation system that is capable of treatment using respiratory-synchronized irradiation with X-rays, even if it does not use a rotating gantry. [Means for solving the problem]

[0006] In order to address the above-mentioned problems, a charged particle beam irradiation system according to one embodiment of the present invention includes a charged particle beam irradiation device into which a transported charged particle beam is incident after being extracted from an accelerator and then extracted toward an isocenter, and a first X-ray generator, a first detector, and a second X-ray generator, and a second detector. The X-rays generated from the first X-ray generator and the second X-ray generator pass through the isocenter and are detected by the first detector and the second detector, respectively. The first X-ray generator and the second X-ray generator are arranged on either side of an imaginary plane formed by multiple trajectories of the charged particle beam that can be selected by the charged particle beam irradiation device. When the side where the charged particle beam enters the charged particle beam irradiation device is defined as the upstream side and the side where the charged particle beam is extracted from the charged particle beam irradiation device is defined as the downstream side, the first detector and the second detector are located upstream or downstream of the first X-ray generator and the second X-ray generator.

[0007] According to the charged particle beam irradiation system of the present invention, even if a rotating gantry is not used, treatment using respiratory-gated irradiation with X-rays can be performed. [Brief explanation of the drawings]

[0008] [Figure 1] Figure 1 is a schematic diagram of a particle beam therapy facility. [Figure 2]FIG. 2(a) is a side view of the vicinity of the irradiation nozzle, and FIG. 2(b) is a front view of the vicinity of the irradiation nozzle. [Figure 3] FIG. 3 is a perspective view of the charged particle beam irradiation system in a state where the X-ray generation unit is not arranged. [Figure 4] FIG. 4(a) is a left side view of the charged particle beam irradiation system shown in FIG. 3, and FIG. 4(b) is a right side view of the charged particle beam irradiation system. [Figure 5] FIG. 5 is a front view of the charged particle beam irradiation system shown in FIG. [Figure 6] FIG. 6(a) is a top view of the charged particle beam irradiation system shown in FIG. 3, and FIG. 6(b) is a rear view of the charged particle beam irradiation system. [Figure 7] FIG. 7 is a perspective view of a charged particle beam irradiation system in which an X-ray generating unit, an X-ray detecting unit, and a mobile vehicle carrying a patient are arranged. [Figure 8] FIG. 8 is a right side view of the charged particle beam irradiation system shown in FIG. [Figure 9] FIG. 9 is a front view of the charged particle beam irradiation system shown in FIG. [Figure 10] FIG. 10 is a diagram for explaining the mechanism of charged particle beam irradiation by the charged particle beam irradiation device. [Figure 11] FIG. 11 is an example of a top view of a treatment room equipped with a charged particle beam irradiation device. [Figure 12] FIG. 12 is a schematic diagram showing the installation conditions of the X-ray imaging device. [Figure 13] FIG. 13 is a diagram showing the relationship between the effective field of view and the installation angle of the X-ray imaging device. [Figure 14] FIG. 14 is a system configuration diagram showing an example of the system configuration of a charged particle beam irradiation device. [Figure 15] FIG. 15 is a block diagram showing an example of the configuration of an information processing device that controls the irradiation of a charged particle beam by a charged particle beam irradiation device. [Figure 16] FIG. 16 is a flowchart showing an example of the control operation of the charged particle beam irradiation device by the information processing device. [Figure 17] FIG. 17 is an example of a timing chart for carrying out therapeutic irradiation by predicting a respiratory waveform. [Figure 18] FIG. 18 is another example of a timing chart for carrying out therapeutic irradiation by predicting a respiratory waveform. [Figure 19] Figure 19(a) is a diagram showing the arrangement relationship between the charged particle beam irradiation system, X-ray generation unit, and detection unit according to this embodiment, Figure 19(b) is a diagram showing the arrangement relationship between the charged particle beam irradiation system, X-ray generation unit, and detection unit in a conventional full gantry, and Figure 19(c) is a diagram showing the arrangement relationship between the charged particle beam irradiation system, X-ray placement unit, and detection unit in a conventional half gantry. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, the charged particle beam irradiation system according to this embodiment will be described in detail with reference to the drawings.

[0010] <Embodiment> Example 1 FIG. 1 is a schematic diagram of a particle beam therapy facility embodying the present invention. A charged particle beam extracted from an accelerator (not shown) passes through a beam transport system 90 and is transported to a treatment room 30. The accelerator is a device that generates a charged particle beam, and may be realized, for example, by a synchrotron, cyclotron, or linear accelerator. The beam transport system 90 includes a vacuum duct and a charged particle beam conditioning device. The charged particle beam conditioning device may include, as appropriate for the specifications, a beam slit for adjusting the beam shape and / or dose, a bending magnet for adjusting the direction of the charged particle beam, a quadrupole magnet for adjusting the beam shape of the charged particle beam, and a steering magnet for fine-tuning the beam position of the charged particle beam, thereby adjusting the beam shape and dose of the charged particle beam. The treatment room is surrounded on all four sides by walls such as concrete for radiation shielding. An irradiation nozzle is located inside the treatment room at the end of the beam transport system, and the charged particle beam passes through the irradiation nozzle and is irradiated onto a patient lying on a treatment table. FIG. 1 shows an example in which irradiation can be performed in two directions: horizontally (by the irradiation nozzle of the charged particle beam irradiation device 50a) and vertically (by the irradiation nozzle of the charged particle beam irradiation device 50b) in a treatment room. In the first embodiment, the horizontal traveling direction of the charged particle beam is designated X, the vertical traveling direction is designated Y, and the direction perpendicular to both X and Y is designated Z. The charged particle beams traveling in the horizontal and vertical directions intersect at a point O called the isocenter. The irradiation nozzle includes a scanning electromagnet for scanning the charged particle beam over the irradiation target shape, a dose monitor for measuring the dose, a position monitor for measuring the beam position, an energy modulation device, and the like. Furthermore, the treatment room is equipped with a positioning device for patient positioning. Patient positioning may refer to determining the relative position of the patient (treatment area) with respect to the irradiation nozzle (with respect to the charged particle beam irradiation device) in the treatment room. The positioning device is composed of an imaging diagnostic device consisting of an X-ray tube as the X-ray generation unit 20, a flat panel detector (hereinafter referred to as FPD) as the detection unit, etc., and a device for transmitting and receiving positioning data. In Figure 1, two FPDs 21 (only one is shown) are installed so as to be suspended from the ceiling (not shown). The X-ray tubes 20 are each installed in a position point-symmetrical to the FPD 21 with point O in between.In FIG. 1, two X-ray tubes are installed under the floor. In this embodiment 1, the FPD 21 is on the ceiling side and the X-ray tube 20 is under the floor, but this does not limit their placement, and the FPD may be on the floor side and the X-ray tube on the ceiling side. Although not shown, other imaging diagnostic devices such as an X-ray CT or MRI may also be installed in the treatment room. Furthermore, in this embodiment, the FPD 21 is suspended from the ceiling, but this is not limited thereto and the FPD may be attached to a device in the treatment room.

[0011] FIG. 2(a) is a schematic side view of the vicinity of the irradiation nozzle realizing the first embodiment, and FIG. 2(b) is a front view of the vicinity of the irradiation nozzle realizing the first embodiment. In FIG. 2, an imaginary plane formed by the charged particle beams in two directions, horizontal and vertical, is defined as a virtual plane P, and point O is within the virtual plane P. If the paired positioning devices are the X-ray tube 20a and the FPD 21a, and the X-ray tube 20b and the FPD 21b, as shown in FIG. 2(a), the FPD 21a and the FPD 21b are installed upstream of the X-ray tube 20a and the X-ray tube 20b in the traveling direction of the charged particle beam. In this embodiment, the FPD 21 is installed upstream of the X-ray tube 20, but the FPD 21 may also be installed downstream of the X-ray tube 20. The X-ray tube 20a and the X-ray tube 20b are positioned symmetrically with respect to the virtual plane P. The FPD 21a and the FPD 21b are positioned symmetrically with respect to the virtual plane P. 2(b), the X-ray tube 20a and the FPD 21a, and the X-ray tube 20b and the FPD 21b are installed point-symmetrically with respect to point O, so that the X-ray tube 20a and the FPD 21b are installed on the same side of the imaginary plane P, and the X-ray tube 20b and the FPD 21a are installed on the opposite side. Note that although an example of plane-symmetrical arrangement with respect to the imaginary plane P is shown here, the X-ray tube 20a and the X-ray tube 20b do not have to be arranged plane-symmetrical with respect to the imaginary plane P. For example, the FPD 21a may be installed further rearward (toward the back of the paper) than shown in the front-to-back (depth) direction of the paper surface of FIG.

[0012] As shown in Figure 2, the Z direction corresponds to the craniocaudal direction of the patient. Although not shown, the patient lies on a treatment table, and patient positioning and treatment irradiation are performed. In this embodiment, the FPDs 21a and 21b and the X-ray tubes 20a and 20b are installed on either side of the virtual plane P, enabling imaging of a wide area in the craniocaudal direction. If the X-ray tubes 20a and 20b and the FPDs 21a and 21b are located on the same side of the virtual plane P, i.e., if they are not arranged symmetrically with respect to the virtual plane P, the imaging area will be on the left and right sides of the body axis, making it impossible to image a wide area of ​​the human body. As a result, to image a wide area, the patient must be moved craniocaudal and imaging must be performed multiple times. In this embodiment, since a wide area can be imaged at once, it is possible to reduce the radiation exposure from X-ray imaging. Furthermore, by reducing the time required for positioning, the utilization efficiency of the treatment room is improved, contributing to increased hospital revenue.

[0013] In the first embodiment, as shown in FIG. 2( a), two FPDs 21 (21a, 21b) can be installed between the horizontal irradiation nozzle and the vertical irradiation nozzle, allowing for effective use of space. Generally, to allow a radiologist to easily grasp the patient's posture in three dimensions when positioning the patient, the X-ray tube 20 and the FPD 21 are installed so that an imaginary plane P formed by the irradiation axis of the charged particle beam and a plane formed by an axis connecting the X-ray tube 20 and the FPD 21 are coplanar. Alternatively, the X-ray tube 20 and the FPD 21 are installed so that the plane formed by the axis connecting the X-ray tube 20 and the FPD 21 is inclined toward the horizontal side from the imaginary plane P. That is, one of the FPDs 21 is installed downstream in the beam propagation direction, toward the open space in the treatment room. In this case, it becomes difficult to access the irradiation port from downstream in the horizontal beam propagation direction, and a configuration is required, such as retracting the FPD 21, to prevent interference between the FPD 21 and a person. In this embodiment, access from the downstream side to the upstream side in the horizontal beam propagation direction is possible without retracting the FPD 21, thereby improving work efficiency. Eliminating the need to retract the FPD 21 is expected to improve installation position accuracy, enabling highly accurate therapeutic irradiation such as respiratory-gated irradiation. Furthermore, if the FPD 21 cannot be installed upstream, the treatment couch may overlap the imaging range, potentially changing the imaging conditions. This embodiment avoids this, allowing consistent imaging conditions regardless of the position of the treatment couch, and is expected to improve treatment accuracy.

[0014] <Example 2> Fig. 3 is a perspective view of a charged particle beam irradiation system in a state where a charged particle beam irradiation device is not arranged, in which an X-ray generation unit and a detection device for detecting the X-rays are not arranged. Fig. 4(a) is a right side view of the charged particle beam irradiation device shown in Fig. 3. Fig. 4(b) is a left side view of the same charged particle beam irradiation device. Fig. 5 is a front view of the charged particle beam irradiation device shown in Fig. 3. Fig. 6(a) is a top view of the charged particle beam irradiation device shown in Fig. 3, and Fig. 6(b) is a rear view of the same charged particle beam irradiation device.

[0015] As shown in FIGS. 3 to 6 (particularly FIG. 4), the charged particle beam irradiation device according to the second embodiment has a shape with a semicircular cutout when viewed from the side, and a charged particle beam is irradiated from the semicircular recess 51 toward an isocenter O at the center of the semicircle. An irradiation nozzle 11 is provided in the recess 51, and the charged particle beam is irradiated from the irradiation nozzle 11 to an affected area (isocenter) that is an irradiation target. The irradiation nozzle 11 is slidable within a semicircular range along guide rails 52 provided in the recess 51 of the charged particle beam irradiation device, and irradiates the charged particle beam from various directions within this range. Note that the irradiation nozzle 11 is not an essential component, and the charged particle beam can be irradiated from the concave surface of the recess 51 even without the irradiation nozzle 11.

[0016] Here, a mechanism for irradiating a charged particle beam by the charged particle beam irradiation system (non-rotating gantry) in this embodiment 2 will be briefly described with reference to Fig. 10. Note that the irradiation nozzle 11 is omitted in Fig. 10.

[0017] 10(a) is a schematic diagram showing the path of a charged particle beam when a bending electromagnet 80 provided in a charged particle beam irradiation device 50 of a charged particle beam irradiation system is viewed from the right side. That is, FIG. 10(a) corresponds to FIG. 4(a) or FIG. 8 described later. As shown in FIG. 10(a), the charged particle beam irradiation device 50 includes a deflecting electromagnet 70 and a bending electromagnet 80.

[0018] The charged particle beam (shown at the left end of FIG. 10) input to the charged particle beam irradiation device is accelerated by an accelerator (not shown) and input to the charged particle beam irradiation device via a beam transport system (not shown). For further details of the charged particle beam irradiation device, see Patent Document 3.

[0019] FIG. 10(a) shows examples of multiple beam paths that differ for each deflection angle φ and convergence angle θ. Here, the traveling direction of the charged particle beam is defined as the X axis, the direction of the magnetic field generated by the bending electromagnet 80 is defined as the Z axis, and the direction perpendicular to the X and Z axes is defined as the Y axis. The bending electromagnet 80 is configured to converge the charged particle beam incident from a wide range of deflection angles φ relative to the X axis on the XY plane to the isocenter O. Note that in FIG. 10(a), the irradiation nozzle is omitted, and for simplicity of explanation, the isocenter O is defined as the origin of the XYZ space, and the upstream side (the accelerator side, the left side of the paper in FIG. 10(a)) is defined as the positive direction of the X axis.

[0020] The deflection angle φ ranges from greater than -90 degrees to less than +90 degrees, and the positive (+Y-axis) deflection angle range and the negative (-Y-axis) deflection angle range may be different (asymmetric). For example, the maximum deflection angle on the positive side (φ=φMAX) may be any of 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, and 85 degrees, and the maximum deflection angle on the negative side (φ=-φMAX) may be any of -10 degrees, -15 degrees, -20 degrees, -25 degrees, -30 degrees, -35 degrees, -40 degrees, -45 degrees, -50 degrees, -60 degrees, -70 degrees, -80 degrees, and -85 degrees. Note that the deflection angle φ is not limited to these angles.

[0021] The bending electromagnet 80 includes one or more coil pairs, which generate a uniform magnetic field (effective magnetic field regions 81a and 81b) oriented in a direction perpendicular to the traveling direction of the charged particle beam and the direction of spread of the deflection angle φ of the charged particle beam (the Z-axis direction in the figure), and are arranged on either side of the path of the charged particle beam. The effective magnetic field region generated by one coil pair of the bending electromagnet 80 has a crescent shape in the XY plane as shown in Figure 10(a), and details of this will be described later. Note that the gap between the opposing coil pairs through which the charged particle beam passes (the distance in the Z-axis direction) is sufficiently small compared to the range of spread of the charged particle beam in the XY plane, so the spread of the charged particle beam in the Z-axis direction will not be considered here.

[0022] 10(b) is a cross-sectional view of the bending electromagnet 80 taken along line AA. The bending electromagnet 80 preferably includes at least two pairs of coils 84a and 84b. Magnetic poles 85a and 85b are incorporated inside the coils 84a and 84b, respectively, and a yoke 86 is connected to the magnetic poles 85a and 85b. A power supply (not shown) is connected to the bending electromagnet 80, and when a current (excitation current) is supplied from the power supply to the coil pairs 84a and 84b, the bending electromagnet 80 is excited and effective magnetic field regions 81a and 81b (collectively referred to as effective magnetic field region 81) are formed.

[0023] The range of the effective magnetic field region 81a and the range of the effective magnetic field region 81b may be different (asymmetric). For example, if the range of the positive (+Y-axis direction) deflection angle φ and the range of the negative (-Y-axis direction) deflection angle φ are asymmetric, the effective magnetic field regions 81a and 81b can be formed asymmetrically accordingly, thereby reducing the unused effective magnetic field region.

[0024] The deflection angle φ of the charged particle beam deflected by the deflection electromagnet 70 and incident on the bending electromagnet 80 ranges from the maximum positive deflection angle (φ=φMAX) to the maximum negative deflection angle (φ=-φMAX), where the maximum positive deflection angle φMAX is an angle of 10 degrees or more and less than 90 degrees, and the maximum negative deflection angle -φMAX is an angle of more than -90 degrees and less than -10 degrees. The deflection angle φ and the irradiation angle θ, which will be described later, are the angles of the path of the charged particle beam with respect to the X-axis on the XY plane.

[0025] A charged particle beam incident within the positive deflection angle range (greater than φ=0 to φMAX) is deflected by the effective magnetic field region 81a of the first coil pair 84a, passes through the irradiation nozzle 11, and is irradiated onto the isocenter O. A charged particle beam incident within the negative deflection angle range (less than φ=0 to −φMAX) is deflected by the effective magnetic field region 81b of the second coil pair 84b, passes through the irradiation nozzle 11, and is irradiated onto the isocenter O. The magnetic fields of the effective magnetic field region 81a and the effective magnetic field region 81b are oriented in opposite directions. Note that a charged particle beam incident from the deflection electromagnet 70 to the bending electromagnet 80 at a deflection angle φ=0 passes through either one of the effective magnetic field regions 81a and 81b, or between both regions 81a and 81b, and is converged onto the isocenter O via the irradiation nozzle (not shown).

[0026] The deflection angle φ of the charged particle beam incident on the bending electromagnet 80 is controlled by a deflection electromagnet 70. The deflection electromagnet 70 generates a magnetic field oriented in a direction (Z-axis in the figure) perpendicular to the traveling direction (X-axis in the figure) of the charged particle beam supplied from an accelerator (not shown), and includes an electromagnet that deflects the passing charged particle beam, and a control unit that controls the strength and direction of the magnetic field (neither of which is shown). The deflection electromagnet 70 deflects the charged particle beam in the XY plane by controlling the strength and direction (Z-axis direction) of the magnetic field, and emits the charged particle beam deflected at the deflection angle φ at a deflection origin Q to the bending electromagnet 80. Here, the deflection origin Q and the isocenter O are on the X-axis (the same horizontal plane).

[0027] 10(c), a calculation formula for forming the effective magnetic field region 81a of the bending electromagnet 80 will be described. In this embodiment, deflection of the charged particle beam in the Z-axis direction is not taken into consideration, so the formation of the effective magnetic field region in the XY plane will be described. The effective magnetic field region 81a of the bending electromagnet 80 will be described, but the same applies to the effective magnetic field region 81b, so a description thereof will be omitted.

[0028] First, the boundary of the effective magnetic field region 81a on the output side 83 of the bending electromagnet 80 for the charged particle beam is determined to be a range at a position equidistant r1 from the isocenter O. Next, the boundary of the effective magnetic field region 81a on the input side 82 of the bending electromagnet 80 for the charged particle beam is determined based on the relational expressions (1) to (5) described below so that the incident charged particle beam is deflected at a deflection angle φ at an imaginary deflection origin Q located at a predetermined distance L from the isocenter O, and converges at the isocenter O. Here, the imaginary deflection origin Q is a point at the center of the deflection electromagnet 70, where it is assumed that the charged particle beam receives a kick of the deflection angle φ over an extremely short distance.

[0029] The charged particle beam transported at a deflection angle φ enters at an arbitrary point P1 on the boundary of the effective magnetic field region 81a on the entrance side 82, performs a circular motion with a curvature radius r2 within the effective magnetic field region 81a (the central angle at this time is (φ+θ)), exits at a point P2 on the boundary of the effective magnetic field region 81a on the exit side 83, and is irradiated toward the isocenter O. In other words, points P1 and P2 are on an arc with a radius r2 and a central angle (φ+θ).

[0030] 10(c), an XY coordinate system is assumed with the isocenter O as the origin on the XY plane. If the angle between the X axis and a line connecting point P2 on the exit side 83 and the isocenter O is defined as the irradiation angle θ, the coordinates (x, y) of point P1 on the entrance side 82, the deflection angle φ, and the distance R between point Q and point P1 can be calculated from the following relational expressions (1) to (4).

[0031]

number

[0032] Here, a magnetic field with a uniform magnetic flux density B is generated in the effective magnetic field region 81a, and if the momentum of the charged particle beam is p (which roughly depends on the accelerator) and the charge is q, the radius of curvature r2 of the charged particle beam deflected in the magnetic field is expressed by equation (5).

[0033]

number

[0034] Based on the above relational expressions (1) to (5), the shape and arrangement of the coil pair 84a and magnetic pole 85a of the bending electromagnet 80 can be adjusted, and the current flowing through the coil pair 84a can be adjusted to adjust the shape of the boundary of the effective magnetic field region 81a. That is, the boundary is determined so that the distance between any point P2 on the boundary of the effective magnetic field region 81a on the exit side 83 and the isocenter O is equal to r1, the magnetic flux density B of the effective magnetic field region 81a is adjusted to determine r2 from expression (5), and the boundary of the effective magnetic field region 81a on the entrance side 82 is determined so that the distance R between point P1 on the boundary of the effective magnetic field region 81a on the entrance side 82 and the deflection starting point Q satisfies the relationship of expression (4). The maximum value of φ in expression (3) becomes the maximum deflection angle φMAX. Although not limited thereto, it is preferable to adjust the positions of the deflection origin Q, the bending electromagnet 80, and the isocenter O so that the charged particle beam passing through the deflection origin Q converges at the isocenter O without being deflected by the bending electromagnet 80, as this simplifies the device configuration.

[0035] The boundary between the effective magnetic field regions 81a, 81b of the bending electromagnet 80 obtained as described above has an ideal shape for converging the charged particle beam to the isocenter O. In reality, even if there is a deviation from this ideal shape or non-uniformity in the magnetic field distribution, the charged particle beam can be deflected to match the isocenter O by finely adjusting the excitation amount (magnetic flux density B) of the bending electromagnet 80 in advance for each deflection angle φ, storing the information in a power supply device, and controlling the deflection angle φ and the amount of current of the bending electromagnet 80 so that they are linked. Furthermore, if the non-uniformity in the magnetic field distribution can be predicted in advance, it is also possible to finely adjust the trajectory of the charged particle beam by correcting the shape and arrangement of the coil pairs 84a, 84b and magnetic poles 85a, 85b of the bending electromagnet 80.

[0036] This allows the charged particle beam to be irradiated at a desired angle to the affected area (isocenter O).

[0037] FIG. 7 is a perspective view showing a charged particle beam irradiation system in which an X-ray generation unit 20 is arranged in a charged particle beam irradiation device and a mobile vehicle 10 carrying a patient is also arranged. FIG. 8 is a right side view of the charged particle beam irradiation device shown in FIG. 7. FIG. 9 is a front view of the charged particle beam irradiation system shown in FIG. 3. The positional relationship between the charged particle beam irradiation device, the X-ray generation unit and its detection unit will be explained using FIGS. 7 to 9. In order to make it easier to see the X-ray generation unit irradiation device and the mobile vehicle 10 carrying a patient, the top wall, the back wall, and the structure on the accelerator side beyond the wall of the charged particle beam irradiation device 50 shown in FIG. 3 are not shown in FIGS. 7 to 9.

[0038] The charged particle beam irradiation device is installed in a specified treatment room. A patient U to be treated is placed on a treatment couch 15 of a mobile vehicle 10 and transported under automatic control to the treatment position of the charged particle beam irradiation device. The treatment couch 15 on which the patient U is placed is connected to an arm 16 provided on the mobile vehicle 10, and by driving this arm 16 (the axis of the arm 16 rotates), the treatment site of the patient U placed on the treatment couch 15 can be moved to the position of the isocenter O of the charged particle beam irradiation device. The mobile vehicle 10 may be automatically controlled by a program or manually controlled by an operator via remote control.

[0039] 7 to 9, the charged particle beam irradiation system 1 includes a charged particle beam irradiation device 50, an X-ray generation unit 20 (20a, 20b), and a detection unit 21 (21a, 21b). As described above, the charged particle beam irradiation device 50 is a device that can irradiate a charged particle beam toward an isocenter.

[0040] The X-ray generation unit 20 is a device that irradiates X-rays, and the detection unit 21 is a device that faces the X-ray generation unit 20 and detects X-rays that have passed through the body of the patient U to generate an X-ray image. In FIGS. 7 to 9, X-rays are schematically shown by dotted lines. The X-ray image generated by the detection unit 21 may be a moving image or a still image. The X-ray image generated by the detection unit 21 is transmitted to an information processing device 100 (described later) that determines the timing of irradiating the charged particle beam.

[0041] 7 to 9, the X-ray generation units 20 (20a, 20b) are provided in the treatment room where the charged particle beam irradiation device is arranged, near the floor, such as under the floor, on both sides of the charged particle beam irradiation device on the irradiation nozzle 11 side (charged particle beam irradiation source side) as viewed from the isocenter O. By providing them under the floor, it is possible to prevent them from interfering with the movement of a vehicle 10 or people within the treatment room, for example.

[0042] The detectors 21 (21a, 21b) that detect the X-rays irradiated from the X-ray generators 20 are provided near the ceiling of the treatment room so as to face the X-ray generators 20 (20a, 20b), respectively. That is, the detectors 21 are installed downstream of the X-ray generators 20 in the direction of travel of the charged particle beam. Note that the positions of the X-ray generators 20 and the detectors 21 may be reversed. That is, the detectors 21 may be arranged upstream of the X-ray generators 20 in the direction of travel of the charged particle beam.

[0043] A dashed-dotted line (17) in FIG. 9 indicates an imaginary plane 17 (corresponding to the above-mentioned imaginary plane P) showing the path through which the charged particle beam passes. As shown in FIG. 9, the charged particle beam passes through the imaginary plane 17, which is a vertical plane passing through the center of the device in FIG. 9. The X-rays irradiated from the X-ray generation unit 20 are irradiated so as to intersect with the imaginary plane 17 and pass through the isocenter O. That is, in the charged particle beam irradiation system 1 according to this embodiment, the X-ray generation unit 20a and the detection unit 21b are arranged on the same side so as not to sandwich the imaginary plane 17, and the X-ray generation unit 20b and the detection unit 21a are also arranged on the same side so as not to sandwich the imaginary plane 17. Note that the X-ray generation unit 20a and the X-ray generation unit 20b do not have to be arranged symmetrically in the treatment room across the imaginary plane 17, and similarly, the detection unit 21a and the detection unit 21b do not have to be arranged symmetrically in the treatment room across the imaginary plane 17.

[0044] Figure 11 is a top view of a treatment room implementing this embodiment. The dimensions of the treatment room are approximately 8 m x 6 m, but are not limited to this. To ensure safety during treatment and reduce the patient's psychological burden, the charged particle beam irradiation device 50 is designed so that only a portion of the tip, including the irradiation nozzle 11, is visible to the patient through a decorative wall 55. Because the decorative wall 55 is often made of plywood, passing X-rays through the decorative wall 55 generally degrades the image quality. Therefore, it is preferable to install the X-ray generator and detector downstream of the decorative wall 55. This is because installing the X-ray generator upstream of the decorative wall 55 would inevitably cause the X-rays to pass through the decorative wall 55 due to their positional relationship with the detector, which is undesirable. Therefore, the X-ray generator 20 and detector 21 must be installed downstream of the decorative wall 55 shown in Figure 11 so that the X-rays pass through the isocenter O. Furthermore, if the edge of the charged particle beam irradiation device 50, the irradiation nozzle 11, or the arm 16 of the mobile vehicle 10 and its drive mechanism 16' interfere with the X-ray imaging area (dashed line in Figure 9), the X-rays will be attenuated and the effective field of view will be narrowed. Therefore, we will describe the installation conditions that enable imaging of a wide area in the craniocaudal direction without changing the imaging conditions or enlarging the treatment room, and that allow respiratory-synchronized irradiation.

[0045] As shown in Figures 12(a) and 12(b), the relative positions of the X-ray generator and detector when viewed from the Z direction are expressed as angle α [deg], and the relative positions of the X-ray generator and detector when viewed from the X direction are expressed as angle β [deg]. The effects of α and β on the effective field of view of the detected image were confirmed. Angle α is the angle of the X-ray flux relative to the horizontal plane on the XY plane, and angle β is the angle of the X-ray flux relative to the horizontal plane on the YZ plane. Here, the effective field of view refers to the area where the X-ray flux generated by the X-ray generator 20 is detected by the detector 21 without interfering with the charged particle beam irradiation device or treatment table (mobile vehicle). Furthermore, when the entire screen area (the entire detection range of the detector 21) is 100, the effective field of view is defined as 80% when the area occupied by the effective field of view is 80.

[0046] The ideal arrangement of the X-ray generators and detectors to form a field of view is one in which the axes connecting the two pairs of X-ray generators 20 and detectors 21 are orthogonal. As shown in Figure 13(a), when β is less than 45 degrees, i.e., the greater the difference between the axes connecting the two pairs of X-ray generators 20 and detectors 21, the less interference with the charged particle beam irradiation device. On the other hand, when α is large, i.e., when the imaging system is tilted toward the irradiation device, the interference between the arm 16 and the drive mechanism 16' increases. When α is small, i.e., when the imaging system is tilted toward the floor, the interference between the arm 16 and the drive mechanism 16' decreases. However, as α becomes smaller, the X-ray generators 20 or detectors 21 located on the floor side extend beyond the decorative wall 55 or do not fit within the treatment room, resulting in an unsuitable arrangement. In Figure 13(b), we examined the interference between the X-ray beam and peripheral devices when α is greater than 70 degrees and β is around 45 degrees. When α was fixed at 74 degrees and the effect of β on the effective visual field was confirmed, the effective visual field was 100% when β was 42<β<45. Furthermore, the effective visual field was 80% when β was 38<β<47. When α was fixed at 78 degrees and the effect of β on the effective visual field was confirmed, the effective visual field was 100% when β was 41<β<46. Furthermore, the effective visual field was 80% when β was 39<β<48. When α was fixed at 82 degrees and the effect of β on the effective visual field was confirmed, the effective visual field was 100% when β was 41<β<48. Furthermore, the effective visual field was 80% when β was 39<β<50. The higher the effective field of view, the wider the imaging range of the X-ray image obtained by X-ray imaging and the better the image quality, so the larger the percentage of the effective field of view, the better. By installing the X-ray generator and detector in an area that is 80% or more of the effective field of view, it is possible to add the function of respiratory-synchronized irradiation and enable high-precision therapeutic irradiation without increasing the size of the device. However, this does not mean that it is necessary to arrange the X-ray generator 20 and detector 21 so that the effective field of view is 80% or more.

[0047] Figure 14 is a system configuration diagram for implementing this embodiment. The system includes an irradiation control system 166 for performing therapeutic irradiation and an indoor equipment control system 161 for patient positioning, with a treatment overall control system 167 as the host system. The treatment overall control system 167 instructs the focusing electromagnet and irradiation nozzle to perform treatment from the desired angle. The focusing electromagnet is excited to perform irradiation from the desired angle, and the irradiation nozzle is driven to irradiate the charged particle beam to the isocenter O. The indoor equipment control system 161 drives the treatment couch 15 via a treatment couch control system 164, and moves the patient to the position where therapeutic irradiation will be performed. Then, an X-ray generator control system 162 performs X-ray exposure, and a detector control system 163 acquires an image.

[0048] According to the present invention, the X-ray generation unit 20 and the detection unit 21 are not installed in the direction of travel of the charged particle beam emitted from the irradiation nozzle, so there is no need to retract the X-ray generation unit 20 and the detection unit 21 during therapeutic irradiation. As a result, the installation accuracy of the X-ray generation unit 20 and the detection unit 21 is not affected by their retraction, so treatment accuracy is not reduced compared to when the X-ray generation unit 20 and the detection unit 21 are retracted to be stored under the ceiling or floor. In addition, the space from the X-ray generation unit 20 to the detection unit 21 is not blocked by the irradiation nozzle. Therefore, patient positioning is possible while changing the therapeutic irradiation angle, shortening treatment time. As a result, the number of patients treated per treatment room can be increased.

[0049] Generally, to make it easier for radiologists to grasp the patient's posture in three dimensions when positioning the patient, the units are installed on a horizontal and vertical beam line, with the imaginary plane 17 formed by the irradiation axis of the charged particle beam and the plane formed by the axis connecting the two pairs of X-ray generators 20 and detectors 21 orthogonal to each other and on the same plane. As long as there are images captured from at least two directions, positioning is possible regardless of the arrangement direction, and therefore the arrangement of the X-ray generators 20 and detectors 21 of the present invention can also achieve patient positioning accuracy equivalent to that of conventional units.

[0050] The present invention contributes to improving treatment accuracy in non-coplanar irradiation, which irradiates treatment beams not only from cross sections perpendicular to the patient's longitudinal axis but also from non-coplanar planes, thereby reducing the dose to normal tissue and adjacent critical organs. After patient positioning, the treatment couch is rotated around the isocenter to initiate irradiation so that irradiation occurs on the desired non-coplanar plane. Treatment is dependent on the accuracy of the treatment couch movement. In the present invention, two pairs of X-ray generators 20 and detectors 21 are positioned along the patient's longitudinal axis, ensuring ample space around the patient. This allows the patient's position to be confirmed using a consistent X-ray imaging system while ensuring sufficient space for the treatment couch to rotate around the isocenter, improving treatment accuracy in non-coplanar irradiation.

[0051] In the rotating gantry, two pairs of X-ray generators 20 and detectors 21 rotate, so patient positioning is performed in the forward direction, and the position of the internal monitor during irradiation depends on the irradiation angle. In this embodiment, in respiratory-gated irradiation, images acquired for patient positioning and internal monitor during irradiation can be evaluated using the same geometric arrangement regardless of the irradiation angle during a series of treatments. When positioning the patient, bones that are less affected by respiratory movement are used as landmarks. Next, in respiratory-gated irradiation, positioning must take into account the relative positional relationship between the bones and the movement of organs that move with respiratory movement, so two-stage position confirmation is performed. Similar confirmation is also performed for irradiation of the prostate, which is affected by the movement of gas in the intestine, or other objects whose movement changes over time due to internal movement during irradiation. In this invention, the geometric arrangement of the two pairs of X-ray generators 20 and detectors 21 is the same during patient positioning and internal monitor, improving irradiation accuracy in treatments that require organ position reproducibility, such as respiratory-gated irradiation.

[0052] In this embodiment, two pairs of X-ray generators 20 and detectors 21 are installed in the patient longitudinal axis direction relative to a non-rotating gantry, thereby simplifying equipment installation and building structure, and enabling maintenance and downsizing of the entire device. In the case of a half-gantry with the same arrangement, at least one of the two pairs of X-ray generators 20 and detectors 21 located upstream of the beam is installed inside the cylindrical rotating gantry. Therefore, complex supports are required for equipment installation inside the rotating gantry, and maintenance work must be performed inside the rotating gantry, placing a heavy burden on the worker. Furthermore, since the irradiation device does not rotate, the building housing the irradiation device can be about half the size of a rotating gantry, which requires a huge cylindrical structure approximately 10 meters in height and depth to accommodate rotation, significantly reducing the introduction cost of the treatment device.

[0053] Example 3 <Configuration of information processing device> 15 is a block diagram showing an example of the configuration of an information processing device 100 that controls a charged particle beam irradiation system. The information processing device 100 is a computer system that controls the irradiation of a charged particle beam from a charged particle beam irradiation device to a treatment site of a patient, and may be realized by a so-called server device, a PC, a tablet terminal, etc., but is not limited to these. As shown in FIG. 15, the information processing device 100 includes a communication unit 110, an input unit 120, a control unit 130, and a calculation unit 140. The information processing device 100 may also include an output unit 150.

[0054] The communication unit 110 is a communication interface capable of communicating with external devices. For example, the communication unit 110 transmits instruction information instructing the irradiation unit of the charged particle beam irradiation device on the timing of irradiating a charged particle beam in accordance with an instruction from the control unit 130. Furthermore, in accordance with an instruction from the communication unit 110 and the control unit 130, the communication unit 110 instructs the X-ray generation unit 20 to irradiate X-rays and instructs the detection unit 21 to transmit an X-ray image. Furthermore, the communication unit 110 receives information related to the treatment of a patient from an external device and transmits it to the control unit 130.

[0055] The input unit 120 is an input interface that has a function of accepting input from an operator of the information processing device 100 and transmitting the input to the control unit 130. The input unit 120 may be realized by, for example, input devices such as a keyboard or a mouse, but is not limited to these. The input unit 120 accepts, for example, input of information related to the treatment of a patient, and transmits the accepted input content to the control unit 130.

[0056] The control unit 130 is a processor having the function of controlling each unit of the information processing device 100. The control unit 130 functions as the information processing device 100 by executing a program stored in the calculation unit 140. The control unit 130 includes a treatment control unit 131 and an X-ray control unit 132 as functions to be performed by the information processing device 100. The treatment control unit 131 has the function of transmitting instruction information to instruct the charged particle beam irradiator to irradiate a charged particle beam via the communication unit 110. The X-ray control unit 132 instructs the X-ray generation unit 20 to irradiate X-rays via the communication unit 110 and acquires an X-ray image detected by the detection unit 21. The X-ray control unit 132 transmits the acquired X-ray image to the treatment control unit 131.

[0057] The calculation unit 140 has a function of analyzing the X-ray image acquired by the X-ray control unit 132 and identifying the relative position of the target area to be treated relative to the patient. The image processing unit 141 performs image processing on the X-ray image acquired by the X-ray control unit 132, analyzes features in the image, and calculates the position of the target treatment area. At this time, an optimal combination of existing image filters (e.g., noise reduction filters and edge enhancement filters) is executed to reduce the burden on the radiologist when positioning the patient, but details thereof are omitted here. The calculation unit 140 also has a memory unit 142. The memory unit 142 is a storage medium capable of storing various programs and various data required for the operation of the information processing device 100. The memory unit 142 can be realized by, for example, a hard disk drive (HDD), a solid state drive (SSD), a flash memory, etc., but is not limited to these. The memory unit 142 stores a learning model 143 for determining the irradiation timing of the charged particle beam. 15, the position of the treatment site may be calculated via a learning model registered in the learning model 143. The learning model 143 is stored in the storage unit 142.

[0058] An example of the learning model 143 is a learning model that learns the correspondence between X-ray images and the positions of organs. The learning model 143 receives inputs of an X-ray image and information indicating a treatment site, and identifies the relative position of the target site relative to the patient. The image processing unit 141 determines whether the target treatment site is located within an irradiation area including the irradiation position (isocenter) of the charged particle beam, and identifies the irradiation timing. Therefore, the learning model 143 is generated by learning a plurality of training data, using as training data information that associates X-ray images with information indicating the positions of various organs in the X-ray images. The algorithm used for the learning model 143 may be, in addition to known algorithms, for example, linear regression (+ regularization), support vector machine (+ kernel method), random forest, neural network, deep learning, or kNN (k-nearest neighbor method), but is not limited thereto. This learning model 143 is preferably a patient-specific model that learns the X-ray images and treatment target positions of each patient to be treated. However, it may also be a general-purpose model that learns the X-ray images and treatment target positions of multiple different patients. Preparing a model specific to each patient is expected to improve treatment accuracy compared to using a general-purpose model, while a general-purpose model eliminates the need to prepare a new model for each treatment of a different patient. The X-ray images used for learning are X-ray images captured by the X-ray generation unit 20 and detection unit 21 positioned as shown in Figures 7 to 9. That is, these are X-ray images obtained by irradiating X-rays in the human body's height direction (longitudinal direction) and obliquely with respect to the horizontal direction relative to the human body's height direction. Training data is generated by associating this X-ray image with information (annotations) indicating which parts of which organs correspond to which parts in the image. In this embodiment, it is preferable to prepare a first learning model 143 corresponding to the X-ray image captured by the detection unit 21a and a second learning model 143 corresponding to the X-ray image captured by the detection unit 21b. Note that the annotation may be added by a medical professional or the like. Furthermore, the image used for learning here may be a digitally reconstructed radiograph generated by simulating an X-ray image from a CT image.Furthermore, multiple learning models may be registered in the learning model 143. Another example of a learning model is a learning model that learns the correspondence between an irradiation site to be treated, the exposure conditions of the X-ray image, and an image filter, and optimizes the image filter. The image filter selected by the learning model 143 is applied to the acquired X-ray image, and the image processing unit 141 analytically detects the target. In this case, the relative position of the target site with respect to the patient is also identified, and the image processing unit 141 determines whether the target treatment site has arrived in an irradiation area including the irradiation position (isocenter) of the charged particle beam, and can identify the relative position of the target site with respect to the patient for specifying the irradiation timing.

[0059] The output unit 150 has a function of outputting information specified by the control unit 130. The output unit 150 may be realized by, for example, a monitor, a speaker, or the like, but is not limited to these. The output of information by the output unit 150 may be realized in the form of transmitting information to an external device. The output unit 150 may output information regarding the treatment area, for example, under instructions from the control unit 130.

[0060] <Operation of information processing device 100> FIG. 16 is a flowchart showing an example of the operation of the information processing device 100 in controlling irradiation of a charged particle beam.

[0061] As shown in FIG. 16, the communication unit 110 of the information processing device 100 receives an X-ray image. The communication unit 110 transmits the received X-ray image to the control unit 130. The control unit 130 accepts input of an X-ray image for performing respiratory synchronization of proton beam therapy (step S1601). That is, the control unit 130 detects X-rays emitted from the X-ray generation unit 20 with the detection unit 21 and accepts input of an X-ray image obtained by the detection. As described above, the X-ray image is not an image of the patient's body irradiated with X-rays parallel to the charged particle beam (the same plane as the virtual plane formed by the irradiation path of the charged particle beam) as in the conventional case, but rather an image of the patient's body irradiated with X-rays that intersect with the virtual plane formed by the line through which the charged particle beam passes. In other words, the image is an image of the patient's body irradiated with X-rays obliquely. The X-ray images received here need only be information that can be used to estimate the state of the organs inside the body, and may be streaming video, a series of still images, or video captured at predetermined time intervals (for example, in 0.1 second increments, but not limited to this).

[0062] Next, the communication unit 110 or the input unit 120 of the information processing device 100 receives input of information about the treatment area of ​​the patient and transmits it to the control unit 130 (step S1602). The information about the treatment area may be information that at least enables the information processing device 100 to identify the relative position of the target area to be treated with respect to the patient.

[0063] The control unit 130 sequentially receives input of X-ray images from the communication unit 110 and inputs the X-ray images and information related to the treatment site to the learning model 143 (step S1603). As a result, the treatment control unit 131 identifies the timing at which the charged particle beam should be irradiated (step S1604).

[0064] Then, the treatment control unit 131 transmits instruction information to instruct the charged particle beam irradiating device to irradiate the charged particle beam at a specific timing via the communication unit 110 (step S1605).

[0065] This allows the information processing device 100 to control the irradiation of the charged particle beam at an appropriate timing.

[0066] In this embodiment, for organs that move due to respiration, the information processing device 100 identifies the relative position of the irradiation target organ and the positional relationship between the irradiation target organ and other organs, thereby reducing the work required by a radiologist and reducing the radiation dose from X-ray exposure. For example, X-ray images of one respiratory cycle are continuously acquired as internal body information, and the information is simultaneously acquired by multiple external information acquisition devices. For example, by synchronizing the respiratory waveform and body surface movement with internal body monitor information, the information processing device 100 can predict the relative position of the irradiation target organ and the positional relationship between other organs and the irradiation target organ using only external information during treatment, allowing for appropriate timing of irradiation. This eliminates the need for exposure during irradiation, thereby reducing the patient's radiation exposure. Furthermore, X-ray imaging can be performed to confirm the relative relationships only when external monitor information indicates an unstable respiratory waveform.

[0067] FIG. 17 shows a first control example in which an unstable respiratory waveform is predicted from data stored in the memory unit 142 of the calculation unit 140 and irradiation is performed. This is a timing chart that schematically illustrates the timing of X-ray irradiation, charged particle beam irradiation, and the like. From top to bottom, FIG. 17 illustrates the waveform of the extracorporeal monitor information, the waveform of the beam-on signal based on the extracorporeal monitor information, the waveform of the irradiation target position information based on the X-ray exposure, the waveform of the X-ray exposure-on signal, the waveform of the beam-on signal based on the irradiation target position information, and the irradiation waveform of the charged particle beam. The extracorporeal monitor information may be information on images of the patient's exterior, such as images of the patient's abdomen, and may be waveform information that schematically indicates the degree of abdominal expansion based on these images. The beam-on signal based on the extracorporeal monitor information is information indicating an irradiation instruction for the charged particle beam, and is information on an irradiation instruction that is issued when the patient's breathing based on the extracorporeal monitor information is stable. The irradiation target position information by X-ray exposure is information indicating the position of the treatment site (the part to be irradiated with the charged particle beam) by imaging the inside of the patient's body through X-ray exposure. The X-ray exposure ON signal is a signal that instructs the X-ray generation unit 20 to irradiate X-rays. The beam ON signal based on the irradiation target position information is a signal that instructs the irradiation of the charged particle beam to the treatment target site identified by X-ray exposure. The irradiation at the bottom of Figure 17 indicates the timing of the charged particle beam irradiation performed by the beam ON signal based on the irradiation target position information.

[0068] First, the image processing unit 141 analyzes external monitor information of the patient under treatment. The external monitor information may be an image of the patient's abdomen or the like. Basically, when the external monitor information indicates that breathing is stable (where the external monitor information in FIG. 17 indicates a stable wave system), the charged particle beam irradiation device turns on the beam-on signal based on the external monitor information and performs charged particle beam irradiation when the patient's body is in a predetermined state, for example, when the value of the external monitor information indicates a positive value (above a predetermined value) in the example of FIG. 17, that is, when the patient's peritoneum is expanded by a predetermined amount or more.

[0069] At this time, the calculation unit 140 references the patient's external monitor information registered in the memory unit 142 and the respiratory waveform data at that time to predict an unstable respiratory waveform in advance. For example, an unstable respiratory waveform 1701, indicated by the dashed line on the respiratory waveform and starting from the arrow in the external monitor information in Figure 17, is predicted. That is, the external monitor information is input to the learning model 143 to estimate whether the patient's respiratory disturbance is likely to occur. If an unstable respiratory waveform occurs, accurate therapeutic irradiation cannot be performed. Therefore, if an unstable respiratory waveform is predicted, X-ray imaging is performed. That is, the X-ray generation unit 20 is instructed to start X-ray exposure and the detection unit 21 is instructed to perform imaging. Then, when the treatment area (irradiation target position information) detected by X-ray exposure reaches the irradiation position, charged particle beam irradiation is performed. While X-ray exposure is being performed, the learning model 143 and the external monitor information continue to predict the respiratory waveform. Then, X-ray imaging is stopped when it is predicted from the external monitor information that the respiratory waveform will stabilize (the stage of the area surrounded by the dotted line 1702 in FIG. 17 ). This reduces unnecessary radiation exposure. Then, control of the charged particle beam irradiation is returned to control based on the external monitor information. Note that the timing for returning to control of the charged particle beam irradiation based on the external monitor information may be when it is predicted that the respiratory waveform will stabilize and when the position of the treatment target area based on the external monitor information is synchronized with the position of the treatment target area detected by X-ray exposure. According to the first control example, X-ray exposure is performed only when breathing is unstable, thereby reducing the processing load on the device compared to continuous X-ray exposure during treatment. Furthermore, according to the first control example, even if detection of the treatment target area based on the external monitor information becomes impossible due to irregular breathing, detection of the treatment target area based on the external monitor information can be resumed.

[0070] Alternatively, in respiratory-gated irradiation, X-ray imaging is performed only at the start and end timings of the irradiation gate (near the start and end of the respiratory gate ON signal), confirming that the irradiation target is within the specified range. If the initial relative relationship is deviated, the irradiation timing can be corrected based on the respiratory waveform, thereby reducing the radiation dose from X-ray imaging. Figure 18 shows a second control example in which X-ray imaging is performed near the ON signal and end of the respiratory gate ON signal, which performs irradiation based on external monitor information. The content of each signal in Figure 18 is the same as in Figure 17, but an irradiation target position prediction waveform indicating the position of the treatment target predicted from the external monitor information has been added. In the second control example, as shown in the figure, the irradiation target position is detected periodically by X-ray exposure. Since the patient's breathing is basically cyclical, X-ray exposure is performed only at the timings of inspiration and expiration to determine whether the irradiation target is located at the desired position. If unstable breathing is not predicted, the charged particle beam is turned ON based on the external monitor information, as in the first control example. That is, the charged particle beam is irradiated at the timing when the extracorporeal monitor information reaches or exceeds a predetermined value.

[0071] On the other hand, if it is detected based on the X-ray image that the irradiation target position is not at the desired position (see dotted line 1801 in FIG. 18 ), it is possible to detect a discrepancy in the relative relationship between the extracorporeal monitor information and the periodic timing of X-ray exposure. If such a discrepancy is detected, the charged particle beam irradiation system switches the X-ray exposure from intermittent to continuous. During continuous X-ray exposure, the position of the treatment target area is continuously identified based on the X-ray image. Then, when the treatment target area reaches the irradiation position, the charged particle beam irradiation system performs charged particle beam irradiation. Then, when the patient's breathing stabilizes, the charged particle beam irradiation system synchronizes the position of the treatment target area identified by X-ray exposure with the position of the treatment target area identified from the extracorporeal monitor information to determine the irradiation timing of the periodic X-ray exposure. Once the irradiation timing is determined, the continuous X-ray exposure is stopped and the system returns to intermittent X-ray exposure.

[0072] Furthermore, when the irradiation beam device 50 having a non-rotating gantry of Example 2 is combined with Example 3, a large space can be secured around the patient, allowing for the installation of an extracorporeal information acquisition device, such as a 3D camera or an ultrasound device. This allows for the installation of a relatively large, radiation-free device, such as an MRI, to more precisely identify the position in addition to extracorporeal information. For example, although MRI has a lower frame rate than X-ray images, it allows the information processing device 100 to more accurately identify the relative position of the organ to be irradiated and the positional relationship between the organ and other organs, enabling irradiation at the appropriate timing.

[0073] FIG. 19 is a diagram schematically illustrating the relative positional relationship between the X-ray generation unit 20 and the detection unit 21 in a conventional full gantry and half gantry, and the relative positional relationship between the X-ray generation unit and the detection unit in the present invention. FIG. 19(a) is a diagram illustrating an example of the arrangement of the X-ray generation unit and the detection unit in a charged particle beam irradiation system other than a rotating gantry according to the present invention. FIG. 19(b) is a diagram illustrating the relative positional relationship between the X-ray generation unit and the detection unit in a full gantry. FIG. 19(c) is a diagram illustrating the relative positional relationship between the X-ray generation unit and the detection unit in a half gantry. The dotted lines in FIGS. 19(a) to 19(c) indicate a virtual plane P(17) generated from multiple trajectories of the irradiated charged particle beam. Furthermore, F1 and F2 respectively indicate the detection units, and X1 and X2 indicate the X-ray generation unit. Regarding upstream and downstream, the upstream indicates the source side of the charged particle beam in the charged particle beam irradiation device, and the downstream indicates the emission side of the charged particle beam.

[0074] 19(a), 19(b), and 19(c), the charged particle beam irradiation system not having a rotating gantry according to the present invention and the conventional full gantry and half gantry systems share the commonality that the axes connecting pairs of X-ray generators (X1, X2) and detectors (F1, F2), i.e., the line connecting the X-ray generator X1 and the detector F1 and the line connecting the X-ray generator X2 and the detector F2 (both not shown), intersect on the imaginary plane P. On the other hand, the charged particle beam irradiation system not having a rotating gantry according to the present invention and the conventional full gantry and half gantry systems differ in that the direction from upstream to downstream of the device is parallel or perpendicular to the imaginary plane P. Furthermore, as is clear from a comparison of FIG. 19(a) and FIG. 19(c), the charged particle beam irradiation system not having a rotating gantry according to the present invention and the conventional full gantry systems differ in that all detectors are located upstream of the X-ray generators. 19(a) and 19(b), the difference between the two is whether the X-ray generation units (X1, X2) and the detection units (F1, F2) are on the same side of the imaginary plane P. From the above, one of the features of the non-rotating gantry charged particle beam irradiation system according to the present invention is that it satisfies the following two conditions: (i) the X-ray generation units and the detection units are not on the same side of the imaginary plane P, and (ii) all the detection units (or X-ray generation units) are arranged upstream of the X-ray generation units (or detection units).

[0075] <Summary> In the charged particle beam irradiation system according to the above embodiment, a rotating gantry is not used as a device for irradiating a charged particle beam, but the first X-ray generation unit and the second X-ray generation unit are arranged symmetrically with respect to a virtual plane formed by a plurality of trajectories of the charged particle beam that can be selected by the charged particle beam irradiation device, and when the side where the charged particle beam enters the charged particle beam irradiation device is defined as the upstream side and the side where the charged particle beam is emitted from the charged particle beam irradiation device is defined as the downstream side, the first detection unit and the second detection unit are positioned upstream or downstream of the first X-ray generation unit and the second X-ray generation unit, thereby making it possible to realize respiratory synchronization using X-rays while suppressing the increase in size of the charged particle beam irradiation device.

[0076] By locating the X-ray generator and detector on the ground and ceiling to the left and right of the charged particle beam irradiation device, they are separated from the irradiation device, ensuring ample space around the patient without the need to retract the X-ray generator and detector during treatment beam irradiation. Therefore, the installation accuracy of the X-ray generator and detector is not affected by insertion / retraction, and treatment accuracy is not reduced. Furthermore, patient positioning is possible while changing the treatment irradiation angle, shortening treatment time and allowing for an increase in the number of patients treated per treatment room. Furthermore, while ensuring space for the treatment couch to rotate around the isocenter, patient positioning can be confirmed with a consistent geometric arrangement for X-ray imaging, improving treatment accuracy in non-coplanar irradiation.

[0077] In respiratory-gated irradiation, images acquired during treatment as patient positioning and internal monitors during irradiation can be evaluated using the same geometric arrangement regardless of the irradiation angle. When positioning the patient, bones, which are less affected by respiratory movement, are used as the reference point, and positioning must also take into account the relative position of the bones and the movement of organs that move with respiration, so two-stage position confirmation is performed. In this case, the geometric arrangement of the two pairs of X-ray generators and detectors during patient positioning and internal monitors is the same, improving the treatment accuracy of respiratory-gated irradiation.

[0078] <Modification> The charged particle beam irradiation system and the information processing device 100 shown in the above embodiment are not limited to the aspects shown in the above embodiment. Appropriate modifications are possible within the knowledge of those skilled in the art. Various modifications will be described below.

[0079] (1) The information processing device 100 may include a learning unit for learning the learning model 143. That is, the information processing device 100 may include a function for generating the learning model 143 by performing learning according to a predetermined algorithm based on a plurality of teacher data.

[0080] The information processing device 100 may also include a re-learning unit that accepts input of new training data and re-learns the learning model 143. By including the re-learning unit, it is possible to obtain more training data (knowledge) and thereby improve the accuracy of estimation.

[0081] (2) In the above embodiment, the case where there is one learning model 143 has been described, but there may be multiple learning models 143. That is, for example, a learning model 143 may be created for each organ to be treated. By subdividing the learning model 143 for each organ, more accurate learning can be performed, and highly accurate charged particle beam irradiation can be achieved.

[0082] (3) In the above embodiment, the learning model 143 may be created for each patient receiving treatment. In this case, the learning model 143 may be trained by adding the patient's treatment area as annotation information to X-ray images. Generating the learning model 143 for each patient enables more accurate charged particle beam irradiation. Furthermore, the learning model 143 may be constructed not only from pre-treatment image information of the patient receiving treatment, but also from patient data, such as X-ray images of unspecified patients who have previously received treatment, before treatment. This increases the amount of training data, which is expected to improve treatment accuracy. This approach is expected to improve not only irradiation control during treatment of organs that undergo respiratory movement, but also positioning accuracy of skeletal positioning using X-ray images of bones.

[0083] (4) In the above embodiment, the angle formed between the X-rays and the imaginary plane 17 is arbitrary, and it is sufficient that the X-ray generation units 20 are provided on both sides of the charged particle beam irradiation device so as not to interfere with the movement of the mobile vehicle 10. In this case, it is preferable to provide the X-ray generation unit 20 as close to the charged particle beam irradiation device as possible to prevent the treatment room from becoming large, but it is also preferable to provide the X-ray generation unit 20 in a position where the housing of the charged particle beam irradiation device and the mobile vehicle 10 when in the treatment position do not interfere with the acquisition of X-ray images. Furthermore, in the above embodiment, an example is shown in which two X-ray generation units 20 and corresponding detection units 21 are provided, but this may be one pair, or more than two pairs of X-ray generation units and corresponding detection units may be provided.

[0084] (5) The program of each embodiment of the present disclosure may be provided in a state stored in a storage medium readable by an information processing device. The storage medium may be a "non-transitory tangible medium" capable of storing the program. The program may include, for example, a software program or an information processing device program.

[0085] The storage medium may, where appropriate, include one or more semiconductor-based or other integrated circuits (ICs) (e.g., field programmable gate arrays (FPGAs), application specific ICs (ASICs), etc.), hard disk drives (HDDs), hybrid hard drives (HHDs), optical disks, optical disk drives (ODDs), magneto-optical disks, magneto-optical drives, floppy diskettes, floppy disk drives (FDDs), magnetic tapes, solid state drives (SSDs), RAM drives, secure digital cards or drives, any other suitable storage media, or any suitable combination of two or more of these. The storage medium may, where appropriate, be volatile, non-volatile, or a combination of volatile and non-volatile.

[0086] Furthermore, the program of the present disclosure may be provided to the information processing device 100 via any transmission medium (such as a communication network or broadcast waves) capable of transmitting the program.

[0087] Furthermore, each embodiment of the present disclosure may also be realized in the form of a data signal embedded in a carrier wave in which a program is embodied by electronic transmission.

[0088] The program of the present disclosure may be implemented using any programming language, such as a scripting language such as JavaScript (registered trademark) or Python, or C language, Go language, Swift, Koltin, or Java (registered trademark).

[0089] (6) The present invention may also be a method for controlling a charged particle beam from a charged particle beam irradiation device by an information processing device 100. That is, one aspect of the present invention is a charged particle beam irradiation device including a bending electromagnet that deflects the charged particle beam to continuously change the irradiation angle of the charged particle beam to an isocenter, and an irradiation nozzle that continuously moves along the shape of the exit side of the effective magnetic field area of ​​the bending electromagnet, an X-ray generation unit that irradiates X-rays, and a detection unit that detects the X-rays, wherein the charged particle beam emitted from the bending electromagnet passes through the irradiation nozzle and is irradiated to the isocenter, and a virtual line connecting the X-ray generation unit and the detection unit is arranged so as not to be parallel to but intersect with a virtual plane formed by the charged particle beam irradiated from the irradiation nozzle to the isocenter. A method for controlling irradiation of a charged particle beam by a charged particle beam irradiation system in which a ray generation unit and a detection unit are arranged, wherein an information processing device executes the following steps: a first reception step of receiving an X-ray image detected by the detection unit; a second reception step of receiving information on the treatment area of ​​a patient receiving treatment with the charged particle beam; and a control step of controlling the timing of irradiating the charged particle beam using a learning model that has learned the relationship between the X-ray image detected by the detection unit and the position of an organ in the X-ray image, the X-ray image received in the first reception step, and information on the treatment area of ​​the patient received in the second reception step.

[0090] (7) The processing in the flowchart shown in Fig. 16 can be modified as needed within the scope in which similar results can be obtained. For example, of the processing in steps S1601 and S1602, the processing in step S1602 may be executed first, or the processing in steps S1601 and S1602 may be executed simultaneously. [Explanation of symbols]

[0091] 1. Charged particle beam irradiation system 10 Mobile vehicles 11 Irradiation nozzle 15 Treatment table 16 Arm 20, 20a, 20b X-ray generating unit 21, 21a, 21b Detector 50 Charged particle beam irradiation device 70 Bending electromagnet 80 Bending electromagnet 100 Information processing device 110 Communications Department 120 Input section 130 Control Unit 131 Treatment Control Unit 132 X-ray control unit 140 Calculation Department 141 Image processing section 142 Storage section 143 Learning Model 150 Output section

Claims

1. a charged particle beam irradiation device into which the transported charged particle beam is incident after being extracted from the accelerator and can be extracted toward an isocenter; The apparatus includes a first X-ray generating unit, a first detecting unit, a second X-ray generating unit, and a second detecting unit, X-rays generated from the first X-ray generating unit and the second X-ray generating unit pass through the isocenter and are detected by the first detecting unit and the second detecting unit, respectively; the first X-ray generating unit and the second X-ray generating unit are arranged on either side of an imaginary plane formed by a plurality of trajectories of the charged particle beam that can be selected by the charged particle beam irradiation device; When a side where the charged particle beam enters the charged particle beam irradiation device is defined as an upstream side and a side where the charged particle beam is emitted from the charged particle beam irradiation device is defined as a downstream side, the first detection unit and the second detection unit are located upstream or downstream of the first X-ray generation unit and the second X-ray generation unit. Charged particle beam irradiation system.

2. 2. The charged particle beam irradiation system according to claim 1, wherein the plurality of orbits are irradiated from irradiation units fixedly installed at regular intervals in the charged particle beam irradiation device.

3. 2. The charged particle beam irradiation system according to claim 1, wherein the first X-ray generation unit and the second X-ray generation unit are arranged symmetrically with respect to the imaginary plane.

4. the plurality of orbits are formed by the influence of a focusing electromagnet having a pair of coils arranged on either side of a path of the charged particle beam; The focusing electromagnet is When a current is input to the coil pair, an effective magnetic field region is generated in which the magnetic field is oriented in a direction (Z axis) perpendicular to the traveling direction (X axis) of the charged particle beam, and the axis perpendicular to both the X axis and the Z axis is defined as the Y axis. In the XY plane, The charged particle beam is deflected at a deflection angle φ with respect to the X axis at the deflection starting point Q, and the charged particle beam is incident on the effective magnetic field region, and is deflected by the effective magnetic field region, and is irradiated onto the isocenter at an irradiation angle θ with respect to the X axis, Any point P2 on the boundary of the effective magnetic field region on the exit side of the charged particle beam is located at an equal distance r1 from the isocenter, A point P1 on the boundary of the effective magnetic field region on the incident side of the charged particle beam and the point P2 are on an arc of radius r2 and central angle (θ+φ), When the distance between the deflection origin Q and the isocenter is L, the distance R between the deflection origin Q and the point P1 is expressed by the following relational expression (4): The charged particle beam irradiation system according to claim 1 , wherein the following is satisfied:

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