Particle beam irradiation device

Abstract

The invention relates to a sub-beam irradiation device which comprises an initial guiding device, a main deflection converging device and a movable deflection focusing device which are sequentially arranged in the transmission direction of a particle beam, and the initial guiding device is used for enabling the particle beam to deviate from the initial advancing direction; the main deflection convergence device comprises a first deflection convergence magnet and a second deflection convergence magnet which are arranged at an interval relative to the initial advancing direction, and a gap is formed between the first deflection convergence magnet and the second deflection convergence magnet; the particle beam after initial deflection passes through the first deflection convergence magnet, the second deflection convergence magnet or the gap; the first deflection convergence magnet and the second deflection convergence magnet are both used for deflecting particle beams passing through the deflection convergence magnets; the movable deflection focusing device is arranged to move on an arc with the isocenter as the circle center so as to receive the particle beams at different positions and enable the particle beams to irradiate the isocenter after deflection. The initial advancing direction is the direction pointing to the isocenter from the deflection starting point of the initial guiding device.

Description

Technical Field

[0001] This invention relates to the field of radiotherapy technology, and more specifically to a particle beam irradiation device. Background Technology

[0002] Radiation therapy is one of the important methods for treating cancer. Particle beams (such as protons and heavy ions), due to their unique "Bragg peak" physics, can precisely kill tumors while better protecting surrounding normal tissues, and have become a cutting-edge direction in radiotherapy technology. Achieving multi-angle irradiation is key to improving treatment precision and developing optimized treatment plans.

[0003] Currently, in order to achieve multi-angle irradiation of the particle beam, the entire beam transport system, including the deflecting magnet and the focusing magnet, is usually mounted on a giant rotating support, which can rotate around the patient continuously for 360-degree irradiation.

[0004] Although rotating supports can achieve flexible and continuous irradiation angles, they are heavy and bulky, expensive, and extremely complex to manufacture and maintain, making them unaffordable for ordinary hospitals and patients. Summary of the Invention

[0005] The purpose of this invention is to provide a particle beam irradiation device that achieves flexible and continuous irradiation angles while making its structure simpler and more compact, thereby reducing costs.

[0006] To achieve the above objectives, the present invention provides a particle beam irradiation device, comprising an initial guiding device, a main deflection and converging device, and a movable deflection and focusing device arranged sequentially along the particle beam transmission direction. The initial guiding device is used to deflect the particle beam from the initial direction of travel. The main deflection and converging device includes a first deflection and converging magnet and a second deflection and converging magnet arranged at intervals relative to the initial direction of travel, with a gap formed between the first deflection and converging magnet and the second deflection and converging magnet. The particle beam after passing through the initial guiding device passes through one of the first deflection and converging magnet, the second deflection and converging magnet, and the gap. Both the first deflection and converging magnet and the second deflection and converging magnet are used to deflect the particle beam passing through them. The movable deflection and focusing device is configured to move on an arc centered at an isocenter point to receive particle beams at different positions and to deflect the particle beams to irradiate the isocenter point. The initial direction of travel is the direction from the deflection starting point of the initial guiding device to the isocenter point.

[0007] Optionally, the initial guiding device is a sector-shaped diode magnet.

[0008] Optionally, when the absolute value of the initial deflection angle of the initial guiding device is less than a preset threshold, the particle beam passes through the initial guiding device and the movable deflection focusing device in sequence and then irradiates the isocenter point at an irradiation angle.

[0009] The initial deflection angle and the illumination angle satisfy the following relationship:

[0010] ,

[0011] ,

[0012] in, The distance between the deflection starting point of the initial guiding device and the isocenter point. The deflection radius of the movable deflection focusing device is given. The deflection angle of the movable deflection focusing device. The illumination angle is... The distance between the position where the particle beam leaves the movable deflection and focusing device and the isocenter point. The initial deflection angle is given.

[0013] Optionally, when the absolute value of the initial deflection angle of the initial guiding device is greater than a preset threshold, the particle beam passes sequentially through the initial guiding device, the first deflection converging magnet, the second deflection converging magnet, and the movable deflection focusing device, and then irradiates the isocenter point at an irradiation angle.

[0014] The initial deflection angle and the illumination angle satisfy the following relationship:

[0015] ,

[0016] ,

[0017] ,

[0018] in, The distance between the deflection starting point of the initial guiding device and the isocenter point. The deflection radius of the movable deflection focusing device is given. The deflection angle of the movable deflection focusing device. The illumination angle is... The distance between the position where the particle beam leaves the movable deflection and focusing device and the isocenter point. Let α be the initial deflection angle, λ be the deflection angle of the first or second deflection converging magnet, λ be the deflection radius of the first or second deflection converging magnet, γ be the angle between the line connecting the position where the particle beam leaves the first or second deflection converging magnet and the position where the particle beam enters the movable deflection converging device, and the line connecting the position where the particle beam leaves the first or second deflection converging magnet and the isocenter point, and d be the distance between the position where the particle beam leaves the first or second deflection converging magnet and the position where the particle beam enters the movable deflection converging device.

[0019] Optionally, the deflection angle of the initial guiding device is adjustable, the deflection radius and deflection angle of the movable deflection focusing device are adjustable, and the deflection angles of the first deflection converging magnet and the second deflection converging magnet are adjustable.

[0020] Optionally, the first deflecting converging magnet and the second deflecting converging magnet are symmetrically arranged with respect to the initial direction of travel.

[0021] Optionally, the movable deflection and focusing device is a composite magnet, which is configured to generate a dipole magnetic field and a quadrupole magnetic field simultaneously within a single magnetic gap. The dipole magnetic field is used to deflect the particle beam passing through it, and the quadrupole magnetic field is used to focus or correct the shape of the particle beam passing through it.

[0022] Optionally, the composite magnet is rectangular or olive-shaped.

[0023] Optionally, the movable deflection and focusing device includes a first composite magnet and a second composite magnet. Both the first composite magnet and the second composite magnet are configured to generate a dipole magnetic field and a quadrupole magnetic field simultaneously within a single magnetic gap. The dipole magnetic field is used to deflect the particle beam passing through it, and the quadrupole magnetic field is used to focus or correct the shape of the particle beam passing through it.

[0024] The moving trajectory of the movable deflection focusing device is divided into a first arc trajectory and a second arc trajectory. The first composite magnet is configured to move on the first arc trajectory, and the second composite magnet is configured to move on the second arc trajectory.

[0025] Optionally, both the first composite magnet and the second composite magnet are rectangular or arc-shaped and symmetrical to each other; and / or

[0026] The first arc-shaped trajectory and the second arc-shaped trajectory are symmetrical with respect to the initial direction of travel.

[0027] The particle beam irradiation device of the present invention achieves particle beam deflection through the cooperation of an initial guiding device, a main deflection and focusing device, and a movable deflection and focusing device, enabling the particle beam to irradiate the isocenter point from different irradiation angles. The main deflection and focusing device consists of two independent deflection and focusing magnets with smaller angles, thus reducing weight, volume, and manufacturing costs. In the composite magnet, the particle beam's trajectory is stable, and the magnet aperture is small, making it easy to ensure efficient, stable, and flexible adjustment of the magnetic field performance, ensuring that a beam with consistent optical quality can be output at different irradiation angles. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of a particle beam irradiation device according to a first embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of particle beam deflection in the case of small-angle deflection of the particle beam irradiation device according to the first embodiment of the present invention.

[0030] Figure 3 This is a schematic diagram of particle beam deflection under large-angle deflection conditions in the particle beam irradiation device according to the first embodiment of the present invention.

[0031] Figure 4 This is a schematic diagram of the structure of a particle beam irradiation device according to a second embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the structure of a particle beam irradiation device according to a third embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram of the structure of a particle beam irradiation device according to a fourth embodiment of the present invention;

[0034] Figure 7 This is a schematic diagram of a particle beam irradiation device according to a fifth embodiment of the present invention. Detailed Implementation

[0035] The preferred embodiments of the present invention are given below with reference to the accompanying drawings and described in detail.

[0036] First Embodiment

[0037] like Figure 1As shown, this embodiment of the invention provides a particle beam irradiation device, which includes an initial guiding device 100, a main deflection and focusing device 200, and a movable deflection and focusing device 300 arranged sequentially along the transmission direction of the particle beam (also known as a charged particle beam). The initial guiding device 100 is used to generate a magnetic field perpendicular to the plane of the paper to cause the particle beam from the particle accelerator (not shown in the figure) (i.e., the particle beam accelerated by the particle accelerator) to deviate from the initial direction of travel in the plane (i.e., the particle beam will undergo initial deflection). The main deflection and focusing device 200 includes a magnetic field perpendicular to the initial direction of travel. A first deflecting and converging magnet 210 and a second deflecting and converging magnet 220 are symmetrically arranged in the forward direction, with a gap 230 formed between them. Because of the gap 230 between the first deflecting and converging magnets 210 and 220, when the initial deflection angle of the particle beam is small, the particle beam after initial deflection will pass through the gap 230 without passing through the first deflecting and converging magnets 210 and 220. However, when the initial deflection angle of the particle beam is large, it will pass through the gap 230. The initially deflected particle beam will pass through one of the first deflecting converging magnet 210 and the second deflecting converging magnet 220 (which one it passes through depends on the initial deflection direction); that is, the particle beam after the initial guiding device 100 will pass through one of the first deflecting converging magnet 210, the second deflecting converging magnet 220, and the gap 230; both the first deflecting converging magnet 210 and the second deflecting converging magnet 220 are used to generate a magnetic field perpendicular to the plane of the paper, causing the particle beam passing through them to deflect in the plane, and the movable deflection focusing device 300 The movable deflection focusing device 300 is configured to move on an arc centered at the isocenter point O to receive particle beams at different positions and ensure that all particle beams at different positions illuminate the isocenter point O. That is, regardless of which of the first deflection converging magnet 210, the second deflection converging magnet 220, and the gap 230 the particle beam passes through, the movable deflection focusing device 300 can move to the corresponding position and receive the particle beam. The movable deflection focusing device 300 is used to deflect the particle beam so that the particle beam illuminates the isocenter point O, which is located in the initial direction of travel of the particle beam.

[0038] The initial guiding device 100 can be a diode magnet, which is fan-shaped (a fan-shaped magnetic pole surface or a fan-shaped magnetic field region is the optimal way to deflect the particle beam bidirectionally in a plane). This diode magnet is used to generate an initial deflection magnetic field, which causes the particle beam passing through it to deviate from its initial direction of travel, i.e., initial deflection occurs. By adjusting the magnitude and direction of the initial deflection magnetic field of the diode magnet, the initial deflection angle of the particle beam can be adjusted. The diode magnet can be a conventional electromagnet or a superconducting magnet, which generates an initial deflection magnetic field through current. By adjusting the magnitude and direction of the current, the magnitude and direction of the initial deflection magnetic field can be adjusted, thereby adjusting the initial deflection direction and angle of the particle beam. The backward extensions of the particle beams leaving the diode magnet from different angles converge at point A, which can be defined as the deflection starting point of the initial guiding device. The line connecting the deflection starting point A and the isocenter point O is set as the X-axis, and the direction along the X-axis from point A to point O is the initial direction of travel of the particle beam. The initial deflection magnetic field of the diode is orthogonal to the X-axis. Let the direction of the initial deflection magnetic field of the diode be the Z-axis, and the direction orthogonal to both the X and Z axes be the Y-axis. Since the Lorentz force exerted on the particle beam by the magnetic field in the Z-direction is only within the XY plane, and the particle beam is deflected only within the XY plane, the Z-axis direction is omitted in the figure; only a schematic diagram of the XY plane is shown.

[0039] The first deflecting and converging magnet 210 and the second deflecting and converging magnet 220 have the same structure. Both can generate a main deflecting magnetic field in the Z-axis direction. The main deflecting magnetic field is used to deflect the particle beam passing through it in the opposite direction to the initial deflection (i.e., the second deflection brings the particle beam closer to the X-axis). Furthermore, the magnetic field directions of the first deflecting and converging magnet 210 and the second deflecting and converging magnet 220 are opposite, thereby enabling particle beams of the same charge to be deflected and converged towards the center. The first deflecting and converging magnet 210 and the second deflecting and converging magnet 220 can be conventional electromagnets or superconducting magnets with magnetic pole surfaces precisely machined according to the design curve, or they can be superconducting magnets that generate this magnetic field distribution using a series of precisely wound superconducting coils.

[0040] The movable deflection and focusing device 300 includes a composite magnet 310, which employs a combined functional design to simultaneously generate a dipole magnetic field and a quadrupole magnetic field along the Z-direction within a single magnetic gap. The dipole magnetic field is used to deflect the particle beam passing through it at a fixed angle (e.g., 45 degrees), while the quadrupole magnetic field is used to focus or correct the shape of the particle beam. The composite magnet 310 can move on an arc centered at point O. Figure 1 In the middle, two semicircular arcs are shown in blue. The larger semicircular arc is the trajectory of the entrance of the composite magnet 310, and the smaller semicircular arc is the trajectory of the exit of the composite magnet 310. Figure 1The composite magnet 310 is also shown in solid and dashed lines. The solid lines represent the actual position of the composite magnet 310, and the dashed lines represent the possible representative position of the composite magnet 310. By moving the composite magnet 310 to a position where it can receive the particle beam, the particle beam is received at the corresponding position, and the particle beam is deflected for the third time and then illuminates the isocenter point O.

[0041] For ease of description, point O is defined as the origin, OA is the positive X-axis, and upwards in the diagram is the positive Y-axis. At this point, the initial direction of the particle beam is the negative X-axis. When the initial guiding device 100 deflects the particle beam along the positive Y-axis away from the X-axis, the initial deflection angle is positive; when the initial guiding device 100 deflects the particle beam along the negative Y-axis away from the X-axis, the initial deflection angle is negative. When the particle beam shines on the isocenter point O above the X-axis, the illumination angle is positive; when the particle beam shines on the isocenter point O below the X-axis, the illumination angle is negative. Except for the initial deflection angle and the illumination angle, all other angles are positive values, with no negative values. The size of the gap 230 can be set such that when the absolute value of the initial deflection angle is less than or equal to a preset threshold, the initially deflected particle beam will pass through the gap 230; and when the absolute value of the initial deflection angle is greater than the preset threshold, the initially deflected particle beam will pass through either the first deflecting converging magnet 210 or the second deflecting converging magnet 220. The preset threshold is related to the size of the gap 230 and can be set as needed. For example, the preset threshold can be 15 degrees. In this way, when the initial deflection angle is within ±15 degrees, the initially deflected particle beam will pass through the gap 230; when the initial deflection angle exceeds 15 degrees, the initially deflected particle beam will pass through the first deflection converging magnet 210; and when the initial deflection angle is less than -15 degrees, the initially deflected particle beam will pass through the second deflection converging magnet 220.

[0042] Due to the presence of gap 230, the particle beam irradiation device exhibits two deflection scenarios: small-angle deflection and large-angle deflection. During small-angle deflection, the particle beam passes sequentially through the initial guiding device 100 and the movable deflecting and focusing device 300 before irradiating the isocenter point O. During large-angle deflection, the particle beam passes sequentially through the initial guiding device 100, the first / second deflecting converging magnets 210 / 220, and the movable deflecting and focusing device 300 before irradiating the isocenter point O. The two deflection scenarios are described in detail below:

[0043] 1. Small angle deflection (initial deflection angle less than or equal to the preset threshold)

[0044] Figure 2 This is a schematic diagram of particle beam deflection under small-angle deflection. The particle beam irradiation device is symmetrical with respect to the X-axis. During the initial deflection, the trajectory of the particle beam is also symmetrical when deflected towards the positive and negative Y-axis. Therefore, for simplicity, Figure 2The diagram only shows the deflection in the positive Y-axis direction. (For example...) Figure 2 As shown, the red line represents the trajectory of a particle beam. B is the position where the particle beam enters the composite magnet 310, C is the position where the particle beam leaves the composite magnet 310, and D is the deflection center of the composite magnet 310. Line segment DB is perpendicular to line segment AB, and line segment DC is perpendicular to line segment CO. The particle beam is equivalent to traveling along a straight line from the deflection point A to point B, then along the arc BC from point B to point C, and finally along a straight line from point C to the isocenter point O. The initial deflection angle of the particle beam is... The deflection angle of the composite magnet 310 is β (the angle between line segments DB and DC), the illumination angle is θ (the angle between line segments OC and OA), the deflection radius of the composite magnet 310 is ρ, the distance between point C and point O is r, and the distance between the deflection starting point A and the isocenter point O is L. The above parameters satisfy the following relationship:

[0045] (1)

[0046] (2)

[0047] During the design phase, parameters can be determined at the critical positions of small-angle and large-angle deflection (i.e., when the initial deflection angle is a preset threshold). r and β can be predetermined based on engineering experience, while ρ can be determined based on the maximum magnetic field of the composite magnet 310 and the maximum energy of the particle beam. Once r, β, and ρ are determined, the effective length of the composite magnet 310 is also determined. The remaining unknown parameters are θ, β, and ρ. And L, at this point, one of them can be set to a fixed value according to actual needs, and then the remaining two values ​​can be obtained according to the above formulas (1) and (2). For example, in practical applications, it is desirable that the preset threshold of the initial deflection angle is 1. Then it can make Then, the corresponding L and θ1 are calculated, where θ1 is the maximum irradiation angle when the deflection is small. Once all parameters are determined, the position of point A, the size and position of the gap, the structure, position, and movement range of the composite magnet 310 can also be determined accordingly. That is, the structure of the particle beam irradiation device when the deflection is small can be determined.

[0048] In application, L, r, and the effective length of the composite magnet 310 remain constant for any target illumination angle smaller than θ1. The deflection radius ρ and deflection angle β can be changed by adjusting the magnetic field of the composite magnet 310. They must not only satisfy formulas (1) and (2), but also the constraint that the chord length of the circular trajectory of the particle beam in the composite magnet remains unchanged (i.e., the effective length of the composite magnet 310 remains unchanged). Therefore, the target illumination angle and its corresponding deflection radius Deflection angle and pre-deflection angle The following relationship must be satisfied:

[0049] (3)

[0050] (4)

[0051] (5)

[0052] in, The β value at the maximum initial deflection angle, obtained from engineering experience during the design phase, can be calculated by simultaneously solving the above equations (3)-(5). corresponding , and Based on calculations , The magnitude of the polar magnetic field of the composite magnet 310 can be obtained; based on the calculated... The magnitude and / or direction of the initial deflection magnetic field of the initial guiding device 100 can be adjusted so that the initial deflection angle is the target value. In this way, the particle beam can illuminate the target at an angle. Irradiation is performed at the isocenter point O. Treatment plans typically include information such as different irradiation angles, the dose at each angle, and the irradiation procedure. In actual use, the initial deflection angle, the deflection radius of the composite magnet, and the deflection angle corresponding to each irradiation angle can be determined first using the treatment plan. After the irradiation angle is determined, the position C where the particle beam leaves the composite magnet 310 can also be determined, i.e., the position of the composite magnet 310 can be determined. Then, based on the initial deflection angle, the deflection radius and deflection angle of the composite magnet, and the position of the composite magnet 310, the composite magnet 310 is moved sequentially to the positions corresponding to different irradiation angles according to the order specified in the irradiation procedure. Simultaneously, the initial deflection angle, the deflection radius and deflection angle of the composite magnet are adjusted to their corresponding values, thereby achieving irradiation at different angles. In practical applications, the isocenter point O represents the location of the patient's lesion. In this way, the particle beam can irradiate the patient's lesion from different irradiation angles, thereby improving the treatment effect.

[0053] 2. Large angle deflection (initial deflection angle is greater than the preset threshold)

[0054] Figure 3 This is a schematic diagram of particle beam deflection under large-angle deflection conditions, and... Figure 2 similar, Figure 3 It only shows the case where the deflection is in the positive direction of the Y-axis. For example... Figure 3 As shown, the red line represents the trajectory of a particle beam, E is the position where the particle beam enters the first deflecting and converging magnet 210, F is the position where the particle beam leaves the first deflecting and converging magnet 210, G is the deflection center of the first deflecting and converging magnet 210, and B, C, D, ... The meanings of α, θ, and ρ are the same as in small-angle deflection. α is the deflection angle of the first deflecting converging magnet 210 (i.e., the angle between line segments GE and GF), λ is the deflection radius of the first deflecting converging magnet 210 (i.e., the lengths of line segments GE and GF), γ is the angle between line segments FB and FO, and d is the distance between the position where the particle beam leaves the first deflecting converging magnet 210 and the position where the particle beam enters the composite magnet 310 (i.e., the length of line segment FB). The parameters satisfy the following relationship:

[0055] (6)

[0056] (7)

[0057] (8)

[0058] During the design phase, the size and location of the gap were already known during the small-angle deflection design. Based on this, the magnetic field boundary shapes of the first deflecting converging magnet 210 and the second deflecting converging magnet 220 need to be further designed. Since the magnetic field boundary shapes of the first deflecting converging magnet 210 and the second deflecting converging magnet 220 are symmetrical, this section only describes how to design the magnetic field boundary shape of the first deflecting converging magnet 210. During the small-angle deflection, the positions and trajectories of L, r, and the composite magnet 310 are already determined, while the desired particle beam trajectory is... Figure 3 The trajectory shown can therefore be... Figure 3 The trajectory is deduced from point O to obtain the magnetic field boundary shape of the first deflecting converging magnet 210. Specifically, during large-angle deflection, the deflection radius ρ and deflection angle β of the composite magnet 310 can be set to remain constant under a specific particle beam energy (the same as at the critical positions of small-angle and large-angle deflection). Thus, for any target illumination angle θ greater than θ1, the position of point C can be obtained. Then, based on the deflection radius ρ and deflection angle β of the composite magnet 310, the position of point B can be obtained. Then, extending a distance d (the value of distance d can be obtained based on engineering experience and remains constant after determination) from point B along the arc BC, the position of point F can be obtained. During large-angle deflection, the deflection radius λ of the first deflection converging magnet 210 can be designed to remain constant under a specific particle beam energy, and its value can be determined based on engineering experience. After λ is determined, an arc passing through point F and tangent to BF is drawn using λ as the radius. Then, a tangent line is drawn from point A through this arc; the point of tangency is point E. After point E is confirmed, the position of point C at the target illumination angle can be obtained. And α. Based on the above method, the positions of points E and F under multiple target illumination angles can be obtained. By smoothly connecting each point F, the outline of the magnetic field outlet of the first deflecting converging magnet 210 can be obtained. By smoothly connecting each point E in sequence, the outline of the magnetic field inlet of the first deflecting converging magnet 210 can be obtained. Therefore, the outline of the magnetic field region of the first deflecting converging magnet 210 can be obtained through the above method. Figure 1 The first deflecting converging magnet 210 and the second deflecting converging magnet 220 in the image show the outline of their magnetic field regions.

[0059] In practical applications, L, r, and d remain constant, while for a particle beam of a specific energy, β, ρ, and They also remain unchanged, meaning that for a particle beam of a specific energy, L, r, d, β, ρ, and θ are known and can be determined by formula (7). The angle is obtained by solving equation (6) to get α corresponding to different target illumination angles, and the corresponding initial deflection angle is obtained by formula (8). Then, adjust the initial guiding device 100 so that its deflection angle corresponds to the target irradiation angle, thus allowing the particle beam to irradiate the isocenter point O from the target irradiation angle. When the particle beam energy changes, the magnetic fields of the first deflecting converging magnet 210 and the composite magnet 310 need to be adjusted to regulate the energy. and ρ.

[0060] The composite magnet 310 can be a conventionally conducting magnet or a superconducting magnet. By changing the magnitude and direction of its current, the magnitude and direction of its magnetic field can be adjusted, thereby adjusting the deflection radius and deflection angle of the composite magnet 310. The composite magnet 310 can be a rectangular magnet with a relatively wide air gap in the magnetic field.

[0061] The movable deflection focusing device 300 may also include an arc track and a drive mechanism. The composite magnet 310 is installed in the arc track and can move in the arc track. The drive mechanism is connected to the composite magnet 310 to drive the composite magnet 310 to move in the arc track.

[0062] The particle beam irradiation device may also include a control device, which is connected to the initial guiding device 100, the main deflection and converging device 200, and the movable deflection and focusing device 300, respectively, and is used to calculate the initial deflection angle under different irradiation angles. The deflection angle β and deflection radius ρ of the composite magnet 310 are calculated, and then the magnitude and / or direction of the magnetic field of the initial guiding device 100 and the composite magnet 310 are adjusted according to the calculated parameter values ​​so that the above parameters can reach the calculated target values, so that the particle beam can irradiate the isocenter point O from different irradiation angles.

[0063] It is understandable that, although the first deflecting converging magnet 210 and the second deflecting converging magnet 220 are symmetrically arranged with respect to the X-axis in the foregoing, they can also be asymmetrically arranged in other embodiments. In this case, the deflection when the initial deflection angle is positive is not the same as the deflection when the initial deflection angle is negative. It needs to be calculated according to the actual structural dimensions, but the calculation principle is the same as that described above. Based on the relevant description of the symmetrical arrangement, those skilled in the art can easily obtain the specific principle of the asymmetrical arrangement, which will not be repeated here.

[0064] The particle beam irradiation device of this invention achieves particle beam deflection through the cooperation of the initial guiding device 100, the main deflection and focusing device 200, and the movable deflection and focusing device 300, enabling the particle beam to irradiate the isocenter point O from different irradiation angles. The main deflection and focusing device 200 is composed of two independent deflection and focusing magnets with smaller angles, thus reducing weight, volume, and manufacturing costs. In the composite magnet 310, the particle beam's trajectory is stable, and the magnet aperture is small, making it easy to ensure efficient, stable, and flexible adjustment of the magnetic field performance, ensuring that a beam with consistent optical quality can be output at different irradiation angles.

[0065] Second Embodiment

[0066] like Figure 4 As shown, the second embodiment of the present invention provides a particle beam irradiation device, which, based on the first embodiment, further includes a scanning magnet 400. The inlet of the scanning magnet 400 is connected to the outlet of the composite magnet 310. The scanning magnet 400 is configured to move synchronously with the composite magnet 310, and the charged particle beam is deflected in a two-dimensional plane by a controlled magnetic field, thereby accurately scanning and covering the tumor target area. The distance r between point C and point O can be determined according to the SAD (source axis distance) of the scanning magnet.

[0067] Third Embodiment

[0068] like Figure 5As shown, the third embodiment of the present invention provides a particle beam irradiation device, which is basically the same in structure as the first embodiment. The only difference is that the movable deflection focusing device 300 of the first embodiment includes only one composite magnet 310, while the movable deflection focusing device 300 of the third embodiment includes two composite magnets, namely a rectangular first composite magnet 320 and a rectangular second composite magnet 330. The first composite magnet 320 moves on a first arc-shaped trajectory, and the second composite magnet 330 moves on a second arc-shaped trajectory. The first arc-shaped trajectory and the second arc-shaped trajectory together form the arc-shaped trajectory of the movable deflection focusing device 300 (i.e., the movement trajectory of the composite magnet 310 in the first embodiment). For example, the movable deflection focusing device 300 has a semi-circular movement trajectory, which can be divided into two symmetrical parts: a quarter-circle above the X-axis and a quarter-circle below the X-axis. The quarter-circle above the X-axis is designated as the first arc trajectory, and the quarter-circle below the X-axis as the second arc trajectory. Thus, the first composite magnet 320 can move above the X-axis, and the second composite magnet 330 moves below the X-axis. The first composite magnet 320 cooperates with the first deflection converging magnet 210 to guide a particle beam with a positive initial deflection angle to irradiate the isocenter position O. The second composite magnet 330 cooperates with the second deflection converging magnet 220 to guide a particle beam with a negative initial deflection angle to irradiate the isocenter position O. The only difference between the first composite magnet 320 and the second composite magnet 330 is that their air gap width is half that of the composite magnet 310 in the first embodiment; otherwise, their remaining structure and operating principle are the same as those of the composite magnet 310.

[0069] By decomposing the composite magnet 310 into a first composite magnet 320 and a second composite magnet 330, the energy storage, manufacturing difficulty and cost of each magnet can be reduced. Each magnet is responsible for half of the initial deflection angle range and can operate independently. It can realize the magnetic field adjustment required for cross-transformation of upper and lower angles and energy regulation, improve the efficiency of angle transformation and energy regulation, and thus improve the treatment efficiency.

[0070] In this embodiment, the particle beam irradiation device may also include a scanning magnet. In this case, only one scanning magnet is needed. The movement trajectory of the scanning magnet is a first arc trajectory and a second arc trajectory. It can be moved downstream of the first composite magnet 320 and the second composite magnet 330 as needed, so as to perform bidirectional deflection scanning of the particle beam.

[0071] Fourth embodiment

[0072] like Figure 6As shown, the fourth embodiment of the present invention provides a particle beam irradiation device, which has a structure basically the same as that of the first embodiment, except that the composite magnet 310 of the first embodiment is rectangular, while the composite magnet 310 of the fourth embodiment is olive-shaped, which can generate an olive-shaped magnetic field region. Compared with rectangular magnets, olive-shaped magnets have lower energy storage and manufacturing costs.

[0073] Fifth embodiment

[0074] like Figure 7 As shown, the fifth embodiment of the present invention provides a particle beam irradiation device, which is basically the same in structure as the third embodiment, except that the first composite magnet 320 and the second composite magnet 330 in the third embodiment are both rectangular, while the first composite magnet 320 and the second composite magnet 330 in the fifth embodiment are both arc-shaped and symmetrical to each other. This reduces the energy storage and material cost of the magnets. The arc shape in this embodiment is half of the olive shape in the fourth embodiment. That is, this embodiment is equivalent to splitting the olive-shaped composite magnet of the fourth embodiment into a symmetrical first composite magnet 320 and a second composite magnet 330. The first composite magnet 320 moves above the X-axis, and the second composite magnet 330 moves below the X-axis. Each is responsible for deflecting the particle beam in its own moving area to the isocenter point O.

[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims of this patent. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A particle beam irradiation device, characterized in that, The device includes an initial guiding device, a main deflection and focusing device, and a movable deflection and focusing device arranged sequentially along the particle beam transmission direction. The initial guiding device is used to deflect the particle beam from the initial direction of travel. The main deflection and focusing device includes a first deflection and focusing magnet and a second deflection and focusing magnet arranged at intervals relative to the initial direction of travel, with a gap formed between the first deflection and focusing magnet and the second deflection and focusing magnet. The particle beam after passing through the initial guiding device passes through one of the first deflection and focusing magnet, the second deflection and focusing magnet, and the gap. Both the first deflection and focusing magnet and the second deflection and focusing magnet are used to deflect the particle beam passing through them. The movable deflection and focusing device is configured to move on an arc centered at an isocenter point to receive particle beams at different positions and to deflect the particle beams to illuminate the isocenter point. The initial direction of travel is the direction from the deflection starting point of the initial guiding device to the isocenter point.

2. The particle beam irradiation device according to claim 1, characterized in that, The initial guiding device is a sector-shaped diode magnet.

3. The particle beam irradiation device according to claim 1, characterized in that, When the absolute value of the initial deflection angle of the initial guiding device is less than a preset threshold, the particle beam passes through the initial guiding device and the movable deflection focusing device in sequence and then irradiates the isocenter point at an irradiation angle. The initial deflection angle and the illumination angle satisfy the following relationship: ， ， in, The distance between the deflection starting point of the initial guiding device and the isocenter point. The deflection radius of the movable deflection focusing device is given. The deflection angle of the movable deflection focusing device. The illumination angle is... The distance between the position where the particle beam leaves the movable deflection and focusing device and the isocenter point. The initial deflection angle is given.

4. The particle beam irradiation device according to claim 3, characterized in that, When the absolute value of the initial deflection angle of the initial guiding device is greater than a preset threshold, the particle beam passes sequentially through the initial guiding device, one of the first deflection converging magnet and the second deflection converging magnet and the movable deflection focusing device, and then irradiates the isocenter point at an irradiation angle. The initial deflection angle and the illumination angle satisfy the following relationship: ， ， ， in, The distance between the deflection starting point of the initial guiding device and the isocenter point. The deflection radius of the movable deflection focusing device is given. The deflection angle of the movable deflection focusing device. The illumination angle is... The distance between the position where the particle beam leaves the movable deflection and focusing device and the isocenter point. Let α be the initial deflection angle, λ be the deflection angle of the first or second deflection converging magnet, λ be the deflection radius of the first or second deflection converging magnet, γ be the angle between the line connecting the position where the particle beam leaves the first or second deflection converging magnet and the position where the particle beam enters the movable deflection converging device, and the line connecting the position where the particle beam leaves the first or second deflection converging magnet and the isocenter point, and d be the distance between the position where the particle beam leaves the first or second deflection converging magnet and the position where the particle beam enters the movable deflection converging device.

5. The particle beam irradiation device according to claim 4, characterized in that, The deflection angle of the initial guiding device is adjustable, the deflection radius and deflection angle of the movable deflection focusing device are adjustable, and the deflection angles of the first deflection converging magnet and the second deflection converging magnet are adjustable.

6. The particle beam irradiation device according to claim 1, characterized in that, The first deflecting converging magnet and the second deflecting converging magnet are symmetrically arranged with respect to the initial direction of travel.

7. The particle beam irradiation device according to claim 1, characterized in that, The movable deflection and focusing device is a composite magnet, which is configured to generate a dipole magnetic field and a quadrupole magnetic field simultaneously within a single magnetic gap. The dipole magnetic field is used to deflect the particle beam passing through it, and the quadrupole magnetic field is used to focus or correct the shape of the particle beam passing through it.

8. The particle beam irradiation device according to claim 7, characterized in that, The composite magnet is rectangular or olive-shaped.

9. The particle beam irradiation device according to claim 1, characterized in that, The movable deflection and focusing device includes a first composite magnet and a second composite magnet. Both the first composite magnet and the second composite magnet are configured to generate a dipole magnetic field and a quadrupole magnetic field simultaneously within a single magnetic gap. The dipole magnetic field is used to deflect the particle beam passing through it, and the quadrupole magnetic field is used to focus or correct the shape of the particle beam passing through it. The moving trajectory of the movable deflection focusing device is divided into a first arc trajectory and a second arc trajectory. The first composite magnet is configured to move on the first arc trajectory, and the second composite magnet is configured to move on the second arc trajectory.

10. The particle beam irradiation device according to claim 9, characterized in that, Both the first composite magnet and the second composite magnet are rectangular or arc-shaped and symmetrical to each other; and / or The first arc-shaped trajectory and the second arc-shaped trajectory are symmetrical with respect to the initial direction of travel.

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