WO2024147262A1 - Particle beam irradiation system and method for moving x-ray radiography apparatus - Google Patents

Abstract

A particle beam irradiation system (1) according to one embodiment of the present invention comprises: an irradiation nozzle (10) which moves, about an isocenter (C), in a circumferential direction between positions equidistant from the isocenter (C), within a circumferential moving range of 240 degrees or less, and which is capable of varying the direction of irradiation of the isocenter (C) with a charged particle beam (B); and an X-ray radiography apparatus (4) which moves in the circumferential direction and which is capable of varying the radiographing direction for an X-ray image of a subject P located at the isocenter (C).

Description

Particle beam irradiation system and method for moving X-ray imaging device

An embodiment of the present invention relates to particle beam irradiation technology.

　Conventionally, a technology is known in which an X-ray imaging device is supported on a rotating gantry for changing the irradiation direction of the irradiation nozzle, and the X-ray imaging device rotates along with the rotating gantry to change the shooting direction of the X-ray image. By supporting the X-ray imaging device on the rotating gantry, it is possible to take X-ray images of the patient from any shooting direction, but the rotating gantry is a large device, which not only limits the space available for its placement, but also increases construction costs. Therefore, there is a demand for miniaturizing particle beam irradiation systems.

There is also a known type of rotating gantry that does not rotate a full 360 degrees, but has a rotation range of 225 degrees or less. However, this type of half rotating gantry does not have a structure for supporting the X-ray imaging device, and the X-ray tube and flat panel detector are fixed to the floor and ceiling.

US Patent Application Publication No. 2006/0067468 International Publication No. 2013/093020

The problem that this invention aims to solve is to enable the user to take an X-ray image of a subject from the shooting direction of their choice, and to miniaturize the entire particle beam irradiation system, including the X-ray imaging device.

1 is a block diagram showing a particle beam irradiation system according to a first embodiment; FIG. FIG. 4 is a side view showing the nozzle support device when the irradiation nozzle is at a 0 degree position. FIG. 13 is a side view showing the nozzle support device when the irradiation nozzle is at a +90 degree position. FIG. 4 is a side view showing the nozzle support device when the irradiation nozzle is at a position of −90 degrees. FIG. 11 is a block diagram showing a particle beam irradiation system according to a second embodiment. FIG. 4 is a front view showing the nozzle support device and the first and second photographing support units. FIG. FIG. FIG. FIG. FIG.

A particle beam irradiation system according to an embodiment of the present invention includes an irradiation nozzle that moves in a circumferential direction around an isocenter at a position equidistant from the isocenter, the range of movement in the circumferential direction being 240 degrees or less, and that can change the irradiation direction of a charged particle beam with respect to the isocenter, and an X-ray imaging device that moves in the circumferential direction and can change the imaging direction of an X-ray image of a subject placed at the isocenter.

Embodiments of the present invention allow the user to capture an X-ray image of a subject from the shooting direction of their choice, and can reduce the size of the entire particle beam irradiation system, including the X-ray imaging device.

Below, embodiments of a particle beam irradiation system and an X-ray imaging device movement method will be described in detail with reference to the drawings. First, a first embodiment will be described with reference to Figs. 1 to 5.

Reference numeral 1 in FIG. 1 denotes a particle beam irradiation system according to the first embodiment. This particle beam irradiation system 1 is a so-called particle beam cancer treatment device that irradiates a charged particle beam B (FIG. 3) such as carbon ions as therapeutic radiation to a lesion tissue (cancer) of a patient P to perform treatment.

Radiation therapy technology using the particle beam irradiation system 1 is also known as heavy particle beam cancer therapy technology. This technology uses carbon ions to pinpoint the cancer lesion (affected area), damaging the cancer lesion while minimizing damage to normal cells. The charged particle beam B is defined as a heavy particle beam that is heavier than helium atoms.

Compared to conventional cancer treatments using X-rays, gamma rays, or proton beams, heavy ion beam cancer treatments have a higher ability to kill cancer lesions, and the radiation dose is low on the surface of the body of patient P (Figure 3), with the radiation dose peaking at the cancer lesion. This allows for fewer irradiations and fewer side effects, and a shorter treatment period.

For example, when the charged particle beam B (Figure 3) passes through the body of the patient P, it loses kinetic energy and decreases in speed, and is subjected to resistance that is approximately inversely proportional to the square of the speed, causing it to suddenly stop when it has slowed to a certain speed. The stopping point of the charged particle beam B is called the Bragg peak, and high energy is released. By aligning this Bragg peak with the position of the diseased tissue (affected area) of the patient P, the particle beam irradiation system 1 can destroy only the diseased tissue while minimizing damage to normal tissue.

As shown in FIG. 1, the particle beam irradiation system 1 includes a beam irradiation device 2, a nozzle support device 3, an X-ray imaging device 4, and a control device 5.

The beam irradiation device 2 includes an ion generator, a beam transport line, and a half rotating gantry. These have the same configuration as the ion generator, beam transport line, and half rotating gantry used in proton beam irradiation devices and the like, and are not shown in the figures as they are conventionally known. Note that the ion generator may include an ion source, a linear accelerator, a circular accelerator, etc.

For example, the ion generator (not shown) has an ion source of carbon ions, which are charged particles, and the charged particle beam B is generated by these carbon ions. The linear accelerator (not shown) is linear in a plan view and accelerates the ions generated by the ion source to form the charged particle beam B. The linear accelerator then introduces this charged particle beam B into a circular accelerator (not shown).

The circular accelerator is a synchrotron or synchrocyclotron, has a ring shape in a plan view, and further accelerates the charged particle beam B. Here, the charged particle beam B is accelerated to about 70% of the speed of light while orbiting the circular accelerator about a million times. The charged particle beam B accelerated by the circular accelerator is then transported to a half rotating gantry (not shown) by a beam transport line (not shown). The circular accelerator may also be a cyclotron.

The particle beam irradiation system 1 is provided with a vacuum duct (not shown) that extends integrally from the ion generator to the half rotating gantry. The inside of this vacuum duct is evacuated, forming a transport path for guiding the charged particle beam B.

The half rotating gantry is installed so that its axis of rotation faces horizontally and rotates around this horizontal axis. The half rotating gantry rotatably supports part of the vacuum duct continuing from the beam transport line, as well as the bending electromagnets and focusing electromagnets that form the transport path.

This half rotating gantry is a smaller device than a full rotation type rotating gantry. A typical full rotation type rotating gantry rotates over a full circumference of 360 degrees, but a half rotating gantry refers to a device whose rotation range is less than two-thirds of the circumference (less than 240 degrees). The half rotating gantry of this embodiment is a device whose rotation range is 180 degrees.

The vacuum duct is first guided from the end of the half rotating gantry along its horizontal axis. Then, once the vacuum duct leaves the horizontal axis of the half rotating gantry, it is directed in a direction perpendicular to the horizontal axis. The irradiation nozzle 10 (Figure 2), where the tip of this vacuum duct is located, is provided in a position close to the patient P.

As shown in FIG. 3, the nozzle support device 3 is a device that supports the irradiation nozzle 10 so that it can move in the circumferential direction. The X-ray imaging device 4 is a device that uses X-rays as imaging radiation to take X-ray images of the patient P as a subject. The X-ray images acquired by the X-ray imaging device 4 are used to position the patient P before irradiation with the charged particle beam B. The X-ray images are also used to track the movement (moving body) of the affected area (internal organs) during irradiation with the charged particle beam B. The X-ray images may also be used to acquire CT (Computed Tomography) images of the patient P.

As shown in FIG. 1, the control device 5 controls the beam irradiation device 2, the nozzle support device 3, and the X-ray imaging device 4. Each component of the control device 5 does not necessarily have to be provided in one computer. For example, one control device 5 may be realized by multiple computers connected to each other via a network. Furthermore, the beam irradiation device 2, the nozzle support device 3, and the X-ray imaging device 4 may each be controlled by a separate computer.

The control device 5 of this embodiment is configured as a computer having hardware resources such as a CPU (Central Processing Unit), GPU (Graphics Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), HDD (Hard Disk Drive) and SSD (Solid State Drive), and information processing by software is realized using the hardware resources as the CPU executes various programs. Furthermore, the method of moving an X-ray imaging device of this embodiment is realized by having the computer execute various programs.

The processing circuit of the control device 5 is, for example, a circuit equipped with a CPU, a GPU, or a dedicated or general-purpose processor. This processor realizes various functions by executing various programs stored in the memory unit of the control device 5. The processing circuit may also be configured with hardware such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit). Various functions can also be realized by such hardware. The processing circuit can also realize various functions by combining software processing by a processor and a program with hardware processing.

In this embodiment, the control device 5 automatically controls various devices, but other configurations are also possible. For example, the control device 5 may be configured to accept input operations from a user (administrator) of the particle beam irradiation system 1 and control various devices. In other words, the control device 5 may be a remote control device for controlling various devices through manual operations by the user.

Next, the nozzle support device 3 and the X-ray imaging device 4 will be described with reference to Figures 2 to 5. Note that the right side of the paper in Figures 3 to 5 will be described as the front side.

As shown in FIG. 2, the irradiation nozzle 10 is provided at the tip side of a vacuum duct (not shown) supported by a half rotating gantry (not shown). This irradiation nozzle 10 is the part that emits the charged particle beam B toward the patient P.

The irradiation nozzle 10 is provided with a scanning electromagnet (not shown). The scanning electromagnet has an X-deflection scanning magnet that deflects and scans the charged particle beam B in the X direction and a Y-deflection scanning magnet that deflects and scans the charged particle beam B in the Y direction when the traveling direction of the charged particle beam B is the Z direction. The scanning electromagnet controls the charged particle beam B to scan the thin charged particle beam B in accordance with the shape of the affected area of the patient P. In other words, the charged particle beam B irradiated from the irradiation nozzle 10 is scanned over a predetermined scanning range in two directions (X direction and Y direction) perpendicular to the traveling direction. The irradiation nozzle 10 may also be provided with a dose monitor, a position monitor, a range shifter, a ridge filter, etc.

In the treatment room in which patient P is placed, an isocenter C is set, which is the position where the charged particle beam B is most concentrated. Before treatment begins, the affected area of patient P is positioned at isocenter C while the position of the affected area is confirmed using X-ray images taken by X-ray imaging device 4, etc.

The irradiation nozzle 10 moves in the circumferential direction at a position equidistant from the isocenter C, with the isocenter C as the center. If a central axis H of the circumferential movement of the irradiation nozzle 10 is defined as an axis passing through the isocenter C, this central axis H coincides with the horizontal axis that is the center of rotation of the half rotating gantry. The charged particle beam B is irradiated from the irradiation nozzle 10 in a direction perpendicular to the central axis H.

As shown in FIG. 3, the irradiation nozzle 10 is set to move in a circumferential direction over a range of 180 degrees around the isocenter C. For example, if the position of the irradiation nozzle 10 when irradiating the charged particle beam B in the horizontal direction is set to 0 degrees, the irradiation nozzle 10 can move over a range from +90 degrees to -90 degrees.

The irradiation direction of the charged particle beam B with respect to the isocenter C can be changed within the range in which the irradiation nozzle 10 moves. For example, as shown in FIG. 4, when the irradiation nozzle 10 is at a position of +90 degrees, the charged particle beam B is irradiated from directly above the patient P. Also, as shown in FIG. 5, when the irradiation nozzle 10 is at a position of -90 degrees, the charged particle beam B is irradiated from directly below the patient P.

The patient P as the subject is placed on a movable stage 11 provided in the treatment room. This movable stage 11 is supported by a movable arm 12 and moves with the patient P placed on it, positioning the affected area of the patient P at the isocenter C. By moving this movable stage 11, the patient P can be moved to the irradiation position of the charged particle beam B and aligned. Therefore, the charged particle beam B can be irradiated with optimal accuracy to the diseased tissue of the patient P. The movable stage 11 and the movable arm 12 are controlled by a control device 5 (Figure 1).

The patient P is positioned at the isocenter C, and by rotating the half rotating gantry (not shown), the irradiation nozzle 10 can be rotated around the stationary patient P. In addition, by changing the orientation of the patient P and rotating the irradiation nozzle 10, the charged particle beam B can be irradiated from any direction around the patient P. Therefore, the burden on the patient P can be reduced, and the affected area can be accurately irradiated with the charged particle beam B from the optimal direction.

The X-ray imaging device 4 of the first embodiment is supported by the nozzle support device 3 and moves in the circumferential direction together with the irradiation nozzle 10, making it possible to change the imaging direction of the X-ray image of the patient P placed at the isocenter C. In this way, the nozzle support device 3 that supports the irradiation nozzle 10 can also be used as a device that supports the X-ray imaging device 4.

The nozzle support device 3 is a device that supports a part of the tip side of the half rotating gantry (not shown). In this way, the irradiation nozzle 10 at the tip side of the half rotating gantry is guided by the nozzle support device 3 and is stably supported in a state where it can move in the circumferential direction.

As shown in Figures 2 and 3, the X-ray imaging device 4 has two X-ray tubes 20 and two flat panel detectors 21. For example, X-rays emitted from one X-ray tube 20A are detected by one flat panel detector 21A. X-rays emitted from the other X-ray tube 20B are detected by the other flat panel detector 21B.

Here, the line connecting one X-ray tube 20A and one flat panel detector 21A is defined as the first virtual line L1. The line connecting the other X-ray tube 20B and the other flat panel detector 21B is defined as the second virtual line L2. In this case, the first virtual line L1 and the second virtual line L2 intersect at the isocenter C. In this embodiment, the angle at which the first virtual line L1 and the second virtual line L2 intersect is in the range of 10 degrees or more and 170 degrees or less.

The nozzle support device 3 comprises a fixed frame 30, a movable frame 31, a C-rail 32, a nozzle base 33, and a support arm 34.

The fixed frame 30 is a member that fixes the C-shaped rail 32 to the floor surface F. For example, the fixed frame 30 is a member that is rectangular when viewed from the front and has an opening cut out into a C-shape (U-shape) when viewed from the side. The patient P is placed in this opening. Two C-shaped rails 32 are fixed to this fixed frame 30, one on each side. In other words, the two C-shaped rails 32 are supported by the fixed frame 30.

The C-rail 32 is a member that is C-shaped (U-shaped) in side view and extends in the circumferential direction. The movable frame 31 is supported by the fixed frame 30 via the C-rail 32, and is a member that moves together with the nozzle base 33 and the support arm 34. The nozzle base 33 is a member that supports the irradiation nozzle 10. This nozzle base 33 is a member that moves along the C-rail 32 via the movable frame 31.

The nozzle support device 3 is equipped with a drive motor (not shown) for moving the movable frame 31. This drive motor is controlled by the control device 5.

The support arms 34 are members that extend circumferentially from the nozzle base 33. As shown in FIG. 3, two support arms 34 are provided that extend upward and downward from the nozzle base 33. These two support arms 34 form a C-shape (U-shape) in side view. When the nozzle base 33 and the support arms 34 move circumferentially, their movement is guided by the C-shaped rails 32.

Now, the movable frame 31 will be described in detail. As shown in Figure 2, the movable frame 31 is provided with two first members 41, one on the left and one on the right, which are guided by a C-shaped rail 32 and form a C-shape (U-shape) in side view (Figure 3). The ends of these first members 41 are connected to each other by two second members 42, one above and one below, which extend in the axial direction. Two third members 43, one on the left and one on the right, which extend in the circumferential direction, are connected to the center of these second members 42. These third members 43 are connected to each other by multiple fourth members 44 which extend in the axial direction.

The nozzle base 33 and the support arm 34 are connected to the third member 43 and the fourth member 44. In this way, the nozzle base 33 and the support arm 34 can be stably moved by the movable frame 31 while being stably fixed to the floor surface F by the fixed frame 30.

The fixed frame 30 and the movable frame 31 may be designed (colored) to match the floor, walls, and ceiling of the treatment room, and may be covered with decorative panels. In this way, the components that make up the nozzle support device 3 will not be visible to the patient P. In other words, the nozzle support device 3 may have a screen function.

As shown in FIG. 3, an X-ray tube 20 is provided at the tip end of each support arm 34. A flat panel detector 21 is provided on an irradiation nozzle 10 fixed to a nozzle base 33 at the base end of the support arm 34. In this way, a configuration can be realized in which the irradiation nozzle 10, X-ray tube 20, and flat panel detector 21 can be moved in the circumferential direction.

The irradiation nozzle 10 and the two flat panel detectors 21 are arranged side by side in the circumferential direction. In this way, X-ray images can be taken of the patient P by moving the flat panel detector 21 in the circumferential direction while taking X-ray images. Furthermore, CT images can also be taken.

The movable stage 11 allows the patient P (subject) to enter through the open portion of the C-rail 32 and be positioned at the isocenter C. For example, the movable stage 11 carrying the patient P can be entered from the direction of the white arrow D in Figure 3. In this way, the patient P can be entered from an appropriate direction and positioned at the isocenter C.

The patient P is positioned so that the body axis extending along the direction of the patient's height coincides with the direction of the central axis H. Furthermore, the body axis of the patient P does not have to coincide with the direction of the central axis H. For example, the patient P may be positioned with the top of the head facing the irradiation nozzle 10. Furthermore, the patient P may be positioned so that the position of the head and feet are opposite to the direction shown in the figure. The position of the patient P may be changed as appropriate depending on the position of the affected area to be irradiated with the charged particle beam B.

A proximity sensor 35 that detects the approach of the mobile platform 11 is provided at the tip side of each support arm 34. The control device 5 that controls the operation of the support arm 34 and the mobile platform 11 performs control to stop the operation of the support arm 34 and the mobile platform 11 when the proximity sensor 35 detects the approach of the mobile platform 11. In this way, it is possible to prevent collision between the support arm 34 and the mobile platform 11.

Next, the second embodiment will be described with reference to Figures 6 to 10. Note that components that are the same as those shown in the previously described embodiment will be given the same reference numerals and duplicated explanations will be omitted. The right side of the paper in Figures 8 to 10 will be described as the front side.

As shown in FIG. 6, the particle beam irradiation system 1A of the second embodiment includes a beam irradiation device 2, a nozzle support device 3A, an X-ray imaging device 4, a control device 5, and an imaging support device 50.

As shown in Figures 7 and 9, the nozzle support device 3A of the second embodiment is a device that supports only the irradiation nozzle 10 so that it can move in the circumferential direction. This nozzle support device 3A has one C-rail 36 that is C-shaped in side view. The irradiation nozzle 10 is supported on this C-rail 36. Although the illustration is simplified to aid understanding, the C-rail 36 has a structure that moves the irradiation nozzle 10 while maintaining a passage path for the charged particle beam B.

The nozzle support device 3A is equipped with a drive motor (not shown) for moving the nozzle base 33 and the irradiation nozzle 10 along the C-shaped rail 36. This drive motor is controlled by the control device 5. The range of movement of the irradiation nozzle 10 in the circumferential direction is 180 degrees or less.

As shown in FIG. 7, the imaging support device 50 is a device that supports the X-ray imaging device 4 so that it can move in the circumferential direction. In the second embodiment, the X-ray imaging device 4 moves in the circumferential direction separately from the irradiation nozzle 10.

This imaging support device 50 includes a first imaging support unit 50A (Fig. 8) that supports two flat panel detectors 21 so that they can move in the circumferential direction, and a second imaging support unit 50B (Fig. 10) that supports two X-ray tubes 20 so that they can move in the circumferential direction.

The first imaging support unit 50A is equipped with one C-rail 51A and one support arm 52A that form a C-shape in side view. Two flat panel detectors 21 are supported in the center of this support arm 52A. The two flat panel detectors 21 move in the circumferential direction as the support arm 52A moves while being guided by the C-rail 51A.

The second imaging support unit 50B is equipped with one C-rail 51B and one support arm 52B that form a C-shape in side view. An X-ray tube 20 is supported at each of the two ends of this support arm 52B. The two X-ray tubes 20 move in the circumferential direction as the support arm 52B moves while being guided by the C-rail 51B.

In addition, a proximity sensor 35 is provided at the tip side of each of the support arms 52A, 52B. When the control device 5 detects the proximity of the mobile platform 11 by the proximity sensor 35, it performs control to stop the operation of the support arms 52A, 52B and the mobile platform 11. In this way, it is possible to prevent collision between the support arms 52A, 52B and the mobile platform 11.

The first and second camera support units 50A and 50B are equipped with drive motors (not shown) for moving the support arms 52A and 52B along the C-rails 51A and 51B. The drive motors are controlled by the control device 5. The range of movement of each of the support arms 52A and 52B in the circumferential direction is 180 degrees or less.

In this way, the X-ray tube 20 and flat panel detector 21 of the X-ray imaging device 4 can be moved to any position in the circumferential direction to perform imaging, regardless of the position of the irradiation nozzle 10.

The present invention has been described above based on the first and second embodiments, but the configurations applied in any of the embodiments may be applied to other embodiments, and the configurations applied in each embodiment may be combined.

In the above embodiment, a half rotating gantry (not shown) is exemplified as an apparatus in which the range in which the irradiation direction of the charged particle beam B can be changed is two-thirds or less of the entire circumference (240 degrees or less), but other configurations may also be used. For example, the above embodiment can also be applied to a slit-type irradiation device 90.

Next, the slit-type irradiation device 90 will be described with reference to Figs. 11 and 12. The right side of Fig. 11 will be described as the front side (forward side) of the slit-type irradiation device 90. If the direction in which the beam pipe 91, which is a vacuum duct through which the charged particle beam B travels, extends and the direction in which the charged particle beam B comes is defined as the X direction, the vertical direction on the page perpendicular to this will be defined as the Y direction, and the direction perpendicular to these will be defined as the Z direction.

First, the beam pipe 91 forms a transport path that guides the charged particle beam B from the ion generator to the slit-type irradiation device 90. In other words, the beam pipe 91 is a sealed continuous space with a sufficient degree of vacuum to allow the charged particle beam B to pass through.

A deflection electromagnet 92 is provided at the end of the beam pipe 91. An expansion duct 93 is provided, which spreads out in a triangular shape (fan shape) in side view from the deflection electromagnet 92. The expansion duct 93 spreads out in the Y direction from the end of the beam pipe 91. A main body 94 is connected to the tip of this expansion duct 93. The main body 94 has a vertically long rectangular shape in side view. The inside of the expansion duct 93 and the main body 94 is an enclosed space with a vacuum level that continues from the beam pipe 91.

Inside the main body 94, there are provided a number of deflection electromagnets 95 (Fig. 12) that deflect the charged particle beam B incident from a wide angle range and focus it on the isocenter C. These deflection electromagnets 95 generate an effective magnetic field region M (Fig. 11). The isocenter C is set as the position where the charged particle beam B is irradiated with the most concentration, and the affected area of the patient P (Fig. 2) is placed at this isocenter C.

For example, inside the main body 94, a pair of deflection electromagnets 95 are provided in the Z direction. Then, two sets of deflection electromagnets 95 are arranged side by side in the Y direction. One set of deflection electromagnets 95 generates one effective magnetic field region M. As shown in FIG. 11, two sets of deflection electromagnets 95, one above the other, can generate two effective magnetic field regions M.

The effective magnetic field region M is generated to have a crescent shape when viewed from the side. By controlling the strength of the effective magnetic field region M, the trajectory of the charged particle beam B can be controlled. The charged particle beam B can be irradiated at any angle centered on the isocenter C. For example, if the inclination of the reference trajectory when the trajectory of the charged particle beam B is not deflected is set to 0 degrees, the irradiation angle of the charged particle beam B can be changed in the range from +85 degrees to -85 degrees centered on the isocenter C.

Note that the reference trajectory refers to the trajectory along which the charged particle beam B flies straight from the beam pipe 91 toward the isocenter C.

In the example of FIG. 11, the two effective magnetic field regions M, one above the other, have the same shape and the same strength. In other words, effective magnetic field regions M that are symmetrical above and below are generated, but other configurations are also possible. For example, the effective magnetic field region M may be asymmetric above and below. In other words, the two effective magnetic field regions M, one above and one below, may have different shapes and strengths. Furthermore, a configuration in which one effective magnetic field region M is generated at either the top or the bottom may also be possible. Note that the center of the range of angles of the charged particle beam B that change in the circumferential direction around the isocenter C may be shifted from the reference trajectory of the charged particle beam B.

Patient P is placed on a movable stage 11. This movable stage 11 is supported by a movable arm 12 and moves with patient P placed on it, positioning the affected area of patient P at isocenter C. By moving this movable stage 11, patient P can be moved to the irradiation position of charged particle beam B and aligned. Therefore, the charged particle beam B can be irradiated to the diseased tissue of patient P with optimal accuracy.

The front side of the main body 94 has a recess 96 that is recessed in a semicircular shape when viewed from the side. An isocenter C is set at the center of the semicircle of this recess 96, and a patient P is placed at this isocenter C. Here, the movable stage 11 can be used to position the patient P at the isocenter C by having the patient P enter the recess 96 on the front side of the main body 94. For example, the movable stage 11 carrying the patient P can be entered from the front direction of the slit-type irradiation device 90 (the direction of the white arrow D in Figure 11). In this way, the patient P can be entered from an appropriate direction and placed at the isocenter C.

A slit 97 is formed on the front side of the main body 94, and is opened so as to extend in the circumferential direction centered on the isocenter C where the patient P is positioned. For example, a vertically long slit 97 (Figure 12) is formed. The slit-type irradiation device 90 emits the charged particle beam B from this slit 97 toward the isocenter C at any angle. The slit 97 is closed with an extremely heat-resistant and extremely cold-resistant polyimide film, and a vacuum is maintained inside the main body 94 in a state where the charged particle beam B can pass through.

An irradiation nozzle 10 that can change the irradiation direction of the charged particle beam B toward the isocenter C is provided near the slit-type irradiation device 90.

The irradiation nozzle 10 moves in a circumferential direction at a position equidistant from the isocenter C, where the patient P (Figure 2) is located as the irradiation target. In other words, the irradiation nozzle 10 can be rotated in one direction and the other direction by a predetermined angle. For example, if the inclination of the reference trajectory of the charged particle beam B is 0 degrees, the irradiation nozzle 10 can move in a range from +85 degrees to -85 degrees. This range of movement is 180 degrees or less, for example, 170 degrees or less.

The irradiation nozzle 10 moves so as to follow the shape (boundary shape) of the exit side of the effective magnetic field region M when viewed from the side. The charged particle beam B traveling from the exit side of the effective magnetic field region M toward the isocenter C passes through the irradiation nozzle 10, and the direction of travel of the charged particle beam B is fine-tuned by the irradiation nozzle 10.

11 and 12, in order to facilitate understanding, the X direction of the slit-type irradiation device 90 is illustrated as being aligned with the horizontal direction. However, when the slit-type irradiation device 90 is actually installed, the entire slit-type irradiation device 90 is inclined. For example, the main body 94 is installed on the floor surface F (FIG. 2) with the longitudinal direction (Y direction) of the main body 94 inclined.

For example, the upper part of the main body 94 is tilted toward the patient P. The irradiation range of the charged particle beam B is a range of any angle centered on the isocenter C, but by tilting the slit-type irradiation device 90, the charged particle beam B can be irradiated from directly above the patient P.

In other words, the slit-type irradiation device 90 is installed in a tilted state so that the reference trajectory when the trajectory of the charged particle beam B is not deflected by the slit-type irradiation device 90 is tilted from the horizontal direction (horizontal axis). In this way, the range of angles at which the charged particle beam B is irradiated to the patient P, who is the object to be irradiated with the charged particle beam B, becomes practical.

The upper part of the main body 94 of the slit-type irradiation device 90 may be tilted away from the patient P. The slit-type irradiation device 90 may also be used without being tilted.

The control device 5 of the above-described embodiment includes a control device, a storage device, an output device, an input device, and a communication interface. Here, the control device includes a highly integrated processor such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an FPGA (Field Programmable Gate Array), or a dedicated chip. The storage device includes a ROM (Read Only Memory), a RAM (Random Access Memory), a HDD (Hard Disk Drive), an SSD (Solid State Drive), etc. The output device includes a display panel, a head-mounted display, a projector, a printer, etc. The input device includes a mouse, a keyboard, a touch panel, etc. This control device 5 can be realized with a hardware configuration using a normal computer.

The program executed by the control device 5 in the above-described embodiment is provided by being pre-installed in a ROM or the like. Additionally or alternatively, this program is provided by being stored in a non-transitory computer-readable storage medium as a file in an installable or executable format. This storage medium includes CD-ROMs, CD-Rs, memory cards, DVDs, flexible disks (FDs), etc.

The programs executed by the control device 5 may also be stored in a computer connected to a network such as the Internet and provided by downloading them via the network. In other words, the programs may be provided from cloud computing resources. A server on the cloud may execute the programs and only the processing results may be provided via the cloud. The control device 5 may also be configured by combining separate modules that independently perform the functions of the components and are interconnected via a network or dedicated lines.

In the above embodiment, a human patient P is exemplified as the subject of X-ray photography, but other aspects are also possible. For example, the subject may be an animal such as a dog or a cat. The particle beam irradiation system 1 may be used when administering radiation therapy to these animals. Furthermore, the body axis of the subject is an axis that extends in the height direction in the case of a human, and an axis that extends in the length direction in the case of an animal such as a dog or a cat.

In the above embodiment, an example was given of an embodiment in which two X-ray tubes 20 and two flat panel detectors 21 are provided, but other embodiments are also possible. For example, an embodiment in which one X-ray tube 20 and one flat panel detector 21 are provided may also be used. In this case, there may be only one support arm 34. Furthermore, an embodiment in which three or more X-ray tubes 20 and three or more flat panel detectors 21 are provided may also be used.

In the above embodiment, the X-ray tube 20 is provided at the tip side of the support arm 34, and the flat panel detector 21 is provided at the base end side of the support arm 34, but other configurations are also possible. For example, the X-ray tube 20 may be provided at the base end side of the support arm 34, and the flat panel detector 21 may be provided at the tip side of the support arm 34. Furthermore, one X-ray tube 20A and the other flat panel detector 21B may be provided at the tip side of the support arm 34, and the other X-ray tube 20B and one flat panel detector 21A may be provided at the base end side of the support arm 34.

In the above embodiment, two C-shaped rails 32 are fixed to the fixed frame 30, but other configurations are also possible. For example, a total of three or more C-shaped rails 32 may be fixed to each of the two sides and the center of the fixed frame 30.

According to at least one of the embodiments described above, the particle beam irradiation system 1 includes an X-ray imaging device 4 that can change the direction in which an X-ray image of a subject placed at the isocenter C is captured. This allows an X-ray image of the subject to be captured from a direction desired by the user, and the particle beam irradiation system 1 as a whole, including the X-ray imaging device 4, can be made smaller.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations can be made without departing from the gist of the invention. These embodiments or variations thereof are within the scope of the invention and its equivalents as described in the claims, as well as the scope and gist of the invention. Note that the term "a" or "an" is not necessarily intended to limit the term to only one, and the term "a" or "an" may refer to multiple entities.

Claims (8)

1. an irradiation nozzle that moves in a circumferential direction around an isocenter at a position equidistant from the isocenter, the range of movement in the circumferential direction being 240 degrees or less, and that can change an irradiation direction of the charged particle beam with respect to the isocenter;
   an X-ray imaging device that moves in the circumferential direction and is capable of changing an imaging direction of an X-ray image of a subject placed at the isocenter;
   Equipped with
   Particle beam irradiation system.
2. a nozzle support device that supports the irradiation nozzle movably in the circumferential direction,
   the X-ray imaging device is supported by the nozzle support device and moves together with the irradiation nozzle in the circumferential direction;
   The particle beam irradiation system according to claim 1 .
3. The nozzle support device is
   At least two C-rails extending in a C-shape along the circumferential direction;
   A nozzle base that supports the irradiation nozzle and moves along the C-shaped rail;
   At least one support arm extending from the nozzle base along the circumferential direction;
   Equipped with
   The X-ray imaging device includes:
   at least one X-ray tube;
   at least one flat panel detector;
   Equipped with
   the X-ray tube is provided on at least one of the distal end and proximal end of the support arm, and the flat panel detector is provided on at least the other of the distal end and proximal end of the support arm;
   The particle beam irradiation system according to claim 2 .
4. The nozzle support device is
   A fixing frame for fixing the C-shaped rail to a floor surface;
   a movable frame supported by the fixed frame and movable together with the nozzle base and the support arm;
   Equipped with
   The particle beam irradiation system according to claim 3 .
5. a movable mounting table which moves with the subject mounted thereon, and causes the subject to enter through an opening in the C-shaped rail and place the subject at the isocenter;
   a proximity sensor provided at a tip end of the support arm and detecting the proximity of the movable mounting table;
   A control device for controlling the operation of the support arm and the movable stage;
   Equipped with
   the control device stops the operation of the support arm and the movable stage when the proximity sensor detects the approach of the movable stage.
   5. The particle beam irradiation system according to claim 3 or 4.
6. The irradiation nozzle and at least two of the flat panel detectors are arranged side by side in the circumferential direction.
   5. The particle beam irradiation system according to claim 3 or 4.
7. a nozzle support device that supports the irradiation nozzle movably in the circumferential direction;
   an imaging support device that supports the X-ray imaging device so as to be movable in the circumferential direction;
   Equipped with
   The X-ray imaging device moves in the circumferential direction separately from the irradiation nozzle.
   The particle beam irradiation system according to claim 1 .
8. an irradiation nozzle that moves in a circumferential direction around an isocenter at a position equidistant from the isocenter, the range of movement in the circumferential direction being 240 degrees or less, and that can change an irradiation direction of the charged particle beam with respect to the isocenter;
   an X-ray imaging device moves in the circumferential direction to change an imaging direction of an X-ray image of a subject placed at the isocenter;
   A method for moving an X-ray imaging device.