JP7145000B2 - Charged particle beam therapy system - Google Patents

Description

The present invention relates to a charged particle beam therapy system.

Conventionally, as a technique in such a field, a charged particle beam therapy apparatus described in Patent Document 1 below is known. This charged particle beam therapy system includes a first bending electromagnet, a second bending electromagnet, and a third bending electromagnet in a direction from the upstream side to the downstream side of the charged particle beam emitted from the accelerator. This charged particle beam therapy system irradiates the patient with the charged particle beam at a desired angle by bending the charged particle beam with these bending electromagnets. The first bending electromagnet deflects the charged particle beam from the accelerator, and the second bending electromagnet deflects the charged particle beam from the first bending electromagnet once horizontally. The third bending electromagnet deflects the charged particle beam from the second bending electromagnet to irradiate the patient.

JP 2012-011038 A

In recent years, there has been a demand for miniaturization of charged particle beam therapy systems. The above-described charged particle beam therapy apparatus can be made smaller in size, particularly in the height direction, compared to a rotating gantry type apparatus. However, in the charged particle beam therapy system described above, the distance from the first bending electromagnet to the third bending electromagnet is long, so there is room for improvement in reducing the footprint.

An object of the present invention is to provide a charged particle beam therapy system that can be miniaturized.

A charged particle beam therapy system of the present invention is a charged particle beam therapy system that irradiates a body to be irradiated with a charged particle beam. A first bending electromagnet is provided on the downstream side of the first bending electromagnet in the traveling direction of the charged particle beam so as to be adjacent to the first bending electromagnet, and deflects the charged particle beam incident from the first bending electromagnet at a second deflection angle. a second bending electromagnet that deflects; and a mounting portion provided downstream of the second bending electromagnet in the traveling direction and on which the object to be irradiated is mounted, wherein the second deflection angle is equal to the first deflection angle. It is an angle that is twice as large and directed to the opposite side of the first deflection angle.

A charged particle beam therapy system includes a first bending electromagnet that deflects a charged particle beam incident from an accelerator side at a first deflection angle according to energy, and a first bending electromagnet downstream of the first bending electromagnet in the traveling direction of the charged particle beam. a second bending electromagnet provided adjacent to the first bending electromagnet for deflecting the charged particle beam incident from the first bending electromagnet at a second deflection angle; As a result, the charged particle beam from the accelerator side is deflected by the first bending electromagnet, deflected by the second bending electromagnet, and then irradiated to the irradiated object mounted on the mounting section. Here, when the deflection angle of the first bending electromagnet is the first deflection angle and the deflection angle of the second bending electromagnet is the second deflection angle, the second deflection angle of the second bending electromagnet is twice the first deflection angle. The angle is doubled and directed to the opposite side of the first deflection angle. Thereby, the second bending electromagnet can irradiate the object to be irradiated with the charged particle beam at the same irradiation angle as the first deflection angle. Due to such a simple relationship, it is possible to irradiate the irradiated object with the charged particle beam at a desired irradiation angle simply by adjusting the magnetic field strengths of the first and second bending magnets. Further, the irradiation angle of the charged particle beam with respect to the object to be irradiated can be adjusted by using the first bending electromagnet and the second bending electromagnet, which are adjacent to each other, without using a large number of bending electromagnets. Therefore, the charged particle beam therapy apparatus can be reduced in size in the height direction compared to a rotating gantry type apparatus, and can reduce the footprint compared to the case where a large number of bending electromagnets are used. can. As described above, it is possible to provide a charged particle beam therapy apparatus that can be miniaturized.

The first bending electromagnet sets a virtual circle having a center point on the base axis of the charged particle beam incident from the accelerator side. , has an incident point of the charged particle beam at the position of the first intersection, and an arc-shaped first The second bending electromagnet has one side surface, and the second bending electromagnet is arranged in an area on the outer peripheral side of the first side surface of the first bending electromagnet. and an arcuate third side surface that is linearly symmetrical with the second side surface with respect to a reference line that is perpendicular to the base axis and passes through the second intersection when viewed from the lateral direction. In such a configuration, the first bending electromagnet deflects the charged particle beam incident from the incident point and emits it from any position on the first side surface. The charged particle beam emitted from the first side immediately enters the second bending electromagnet from the second side. At this time, the second side surface has a shape corresponding to the arcuate first side surface. Also, the third side surface has an arcuate shape that is symmetrical with the second side surface with respect to the reference line. Therefore, the charged particle beam draws a line-symmetrical trajectory with respect to the reference line in the second bending electromagnet, and emerges from the third side surface in a line-symmetrical manner with respect to the incident state on the second side surface.

A charged particle beam therapy system according to the present invention is a charged particle beam therapy system for irradiating a body to be irradiated with a charged particle beam, comprising: a first bending electromagnet for deflecting a charged particle beam incident from an accelerator side according to energy; a second bending electromagnet provided adjacent to the first bending electromagnet downstream of the first bending electromagnet in the traveling direction of the charged particle beam and deflecting the charged particle beam incident from the first bending electromagnet; and a mounting portion provided downstream of the second bending electromagnet and on which the object to be irradiated is mounted, wherein the first bending electromagnet has a central point on the axis of the charged particle beam incident from the accelerator side. set a virtual circle having The arc has an arcuate first side surface in at least any part of the range of 90° from the second intersection point toward the first intersection point, and the second bending electromagnet is located on the first side surface of the first bending electromagnet. A second arc-shaped side surface that is arranged in an area on the outer peripheral side and has a shape corresponding to the first side surface when viewed from the lateral direction, and a reference that is perpendicular to the base axis and passes through the second intersection when viewed from the lateral direction. and an arcuate third side surface that is line-symmetrical with the second side surface with respect to the line.

A charged particle beam therapy system includes a first bending electromagnet that deflects a charged particle beam incident from the accelerator side according to energy, and the first bending electromagnet downstream of the first bending electromagnet in the traveling direction of the charged particle beam. and a second bending electromagnet provided adjacent to the first bending electromagnet for deflecting the charged particle beam incident from the first bending electromagnet. As a result, the charged particle beam from the accelerator side is deflected by the first bending electromagnet, deflected by the second bending electromagnet, and then irradiated to the irradiated object mounted on the mounting section. Here, the first bending electromagnet deflects the charged particle beam incident from the incident point and emits it from any position on the first side surface. The charged particle beam emitted from the first side immediately enters the second bending electromagnet from the second side. At this time, the second side surface has a shape corresponding to the arcuate first side surface. Also, the third side surface has an arcuate shape that is symmetrical with the second side surface with respect to the reference line. Therefore, the charged particle beam draws a line-symmetrical trajectory with respect to the reference line in the second bending electromagnet, and emerges from the third side surface in a line-symmetrical manner with respect to the incident state on the second side surface. Due to such a simple relationship, it is possible to irradiate the irradiated object with the charged particle beam at a desired irradiation angle simply by adjusting the magnetic field strengths of the first and second bending magnets. Further, the irradiation angle of the charged particle beam with respect to the object to be irradiated can be adjusted by using the first bending electromagnet and the second bending electromagnet, which are adjacent to each other, without using a large number of bending electromagnets. Therefore, the charged particle beam therapy apparatus can be reduced in size in the height direction compared to a rotating gantry type apparatus, and can reduce the footprint compared to the case where a large number of bending electromagnets are used. can. As described above, it is possible to provide a charged particle beam therapy apparatus that can be miniaturized.

The charged particle beam is provided downstream of the first bending electromagnet in the traveling direction of the charged particle beam so as to be adjacent to the first bending electromagnet. An electromagnet is further provided, and the first bending electromagnet has an arc-shaped fourth side surface on at least one portion of the lower arc of the circle within a range of 90° from the second intersection point to the first intersection point. , the third bending electromagnet is disposed in an area on the outer peripheral side of the fourth side surface of the first bending electromagnet, and has an arc-shaped fifth side surface having a shape corresponding to the fourth side surface when viewed from the lateral direction, and Seen, it may have an arcuate sixth side surface that is line-symmetrical with the fourth side surface with respect to a reference line that is perpendicular to the base axis and passes through the second intersection point. According to such a configuration, by using the third bending electromagnet, it is possible to irradiate the object to be irradiated with the charged particle beam at a desired irradiation angle from below.

The second deflection angle by the second bending magnet may be twice as large as the first deflection angle by the first bending magnet and directed to the opposite side of the first deflection angle. Thereby, the second bending electromagnet can irradiate the object to be irradiated with the charged particle beam at the same irradiation angle as the first deflection angle.

According to the present invention, it is possible to provide a charged particle beam therapy system that can be miniaturized.

1 is a schematic side view showing a charged particle beam therapy system according to an embodiment; FIG. (a) is a cross-sectional view taken along line IIa-IIa shown in FIG. 1, and (b) is a cross-sectional view taken along line IIb-IIb shown in FIG. It is a schematic side view which shows the specific structure of irradiation nozzle vicinity. FIG. 4 is a schematic side view showing the positional relationship of each bending electromagnet; FIG. 4 is a schematic side view for explaining the behavior of charged particle beams; FIG. 4 is a schematic side view for explaining the behavior of charged particle beams;

A charged particle beam therapy system according to an embodiment of the present invention will be described below with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted.

As shown in FIG. 1, a charged particle beam therapy apparatus 1 according to one embodiment of the present invention is an apparatus used for cancer treatment by radiotherapy, and charged particles generated by an ion source (not shown) Accelerator 2 that accelerates and emits a charged particle beam, an irradiation unit 3 that irradiates the object to be irradiated with the charged particle beam, a placement unit 4 on which the patient is placed, and a charged particle beam emitted from the accelerator 2. and a beam transport line 6 for transporting to the irradiation unit 3 . Accelerator 2 is arranged in accelerator chamber 10 . The irradiation section 3 and the mounting section 4 are arranged in the irradiation chamber 11 . The accelerator chamber 10 and the irradiation chamber 11 are each constituted by a space surrounded by walls. A wall 12 separates the accelerator chamber 10 from the irradiation chamber 11 . A beam transport line 6 passes through the wall 12 .

In the following description, the terms "X-axis direction" and "Y-axis direction" are used. The X-axis direction is the direction from the accelerator 2 to the irradiation unit 3 . The positive side in the X-axis direction corresponds to the irradiation section 3 side, and the negative side corresponds to the accelerator 2 side. The Y-axis direction is a horizontal direction perpendicular to the X-axis direction, and corresponds to the "horizontal direction" in the claims. The positive side in the Y-axis direction corresponds to the back side of the paper in FIG. 1, and the negative side corresponds to the front side of the paper in FIG.

The accelerator 2 is a device that accelerates charged particles and emits a charged particle beam B having a preset energy. Examples of the accelerator 2 include a cyclotron, a synchrotron, a synchrocyclotron, a linac, and the like. A charged particle beam B generated by the accelerator 2 is transported to the irradiation unit 3 by a beam transport line 6 . The beam transport line 6 connects the accelerator 2 and the irradiation section 3 and transports the charged particle beam B emitted from the accelerator 2 to the irradiation section 3 . A quadrupole electromagnet or the like is provided in the beam transport line 6 . The charged particle beam B travels straight from the accelerator 2 toward the irradiation unit 3 along the beam transport line 6 toward the positive side in the X-axis direction. The base axis of the charged particle beam B in this traveling state is defined as the base axis AX.

The irradiation unit 3 irradiates the affected part of the patient W (body to be irradiated) with the charged particle beam B. As shown in FIG. The charged particle beam B is obtained by accelerating charged particles at high speed, and includes, for example, proton beams, heavy particle (heavy ion) beams, and electron beams. The irradiation unit 3 can irradiate the patient W with the charged particle beam B at a desired irradiation angle. The irradiation unit 3 includes a first bending electromagnet 21, a second bending electromagnet 22A, and a third bending electromagnet 22B. A pair of bending electromagnets 21, 22A, and 22B are provided so as to face each other while being separated from each other in the Y-axis direction (see FIG. 2).

The first bending electromagnet 21 is an electromagnet that deflects the charged particle beam B incident from the accelerator 2 side according to energy. The first bending electromagnet 21 deflects upward the charged particle beam B traveling from the accelerator 2 via the beam transport line 6, thereby guiding it to the second bending electromagnet 22A. Alternatively, the first bending electromagnet 21 deflects downward the charged particle beam B traveling from the accelerator 2 via the beam transport line 6, thereby guiding it to the third bending electromagnet 22B.

When viewed from the Y-axis direction, the first bending electromagnet 21 has a D-shape. The first bending electromagnet 21 has a vertically symmetrical shape with respect to the base axis AX. The first bending electromagnet 21 is configured in a rectangular shape in a region on the negative side in the X-axis direction (that is, on the upstream side in the traveling direction of the charged particle beam B), and in a region on the positive side in the X-axis direction (that is, on the It is formed in a semicircular shape that protrudes toward the positive side in the X-axis direction on the downstream side in the traveling direction). The first bending electromagnet 21 has a side surface 31 extending vertically at the negative end in the X-axis direction. The side surface 31 is a plane perpendicular to the base axis AX. Therefore, the charged particle beam B from the accelerator 2 is incident on the first bending electromagnet 21 with the side surface 31 as the incident surface. The first bending electromagnet 21 has a side surface 32A (first side surface) corresponding to the upper half of the arc-shaped side surface on the positive side in the X-axis direction. The first bending electromagnet 21 also has a side surface 32B (fourth side surface) which is a portion corresponding to the lower half of the arc-shaped side surface on the positive side in the X-axis direction. The side surface 32A and the side surface 32B are curved surfaces that are continuous with each other. The charged particle beam B deflected within the first bending electromagnet 21 is emitted from the first bending electromagnet 21 with the side surface 32A or the side surface 32B as an emission surface. The first bending electromagnet 21 includes a core portion 21a and a coil portion 21b wound around the outer peripheral portion of the core portion 21a.

As shown in FIG. 2B, the pair of first bending electromagnets 21 are arranged so as to be separated from each other in the Y-axis direction. Thereby, a space SP1 is formed between the pair of first bending electromagnets 21 . The pair of first bending electromagnets 21 are supported by the wall portion 43 on the side opposite to the space SP1. Since the space SP1 is a space in which the charged particle beam B travels, it is evacuated.

As shown in FIG. 1, the second bending electromagnet 22A is provided downstream of the first bending electromagnet 21 in the traveling direction of the charged particle beam B so as to be adjacent to the first bending electromagnet 21. It is an electromagnet that deflects the charged particle beam B incident from 21 . The second bending electromagnet 22A is provided obliquely above the first bending electromagnet 21 at a position on the positive side in the X-axis direction. The second bending electromagnet 22</b>A bends the charged particle beam B incident from the first bending electromagnet 21 in an arc shape so as to project upward, and then emits the bent beam toward the mounting section 4 .

When viewed from the Y-axis direction, the second bending electromagnet 22A has a substantially fan-like shape. The second bending electromagnet 22A has a line-symmetrical shape with respect to the reference line CL1 extending in the vertical direction. The reference line CL1 is a line that is perpendicular to the base axis AX and passes through the vertex TP on the positive side of the first bending electromagnet 21 in the X-axis direction (see FIG. 4). The second bending electromagnet 22A has an arc-shaped side surface 33A (second side surface) having a shape corresponding to the side surface 32A. The charged particle beam B from the first bending electromagnet 21 is incident on the second bending electromagnet 22A with the side surface 33A as an incident surface. The side surface 33A is a curved surface that curves concavely toward the inside of the second bending electromagnet 22A. The second bending electromagnet 22A has an arc-shaped side surface 34A (third side surface) that is line-symmetrical with the side surface 33A with respect to the reference line CL1. The charged particle beam B deflected within the second bending electromagnet 22A is emitted from the second bending electromagnet 22A with the side surface 34A as an emission surface. In addition, the second bending electromagnet 22A has a side surface 36A that forms a semicircular arc convex upward between the upper end of the side surface 33A and the upper end of the side surface 34A. The second bending electromagnet 22A includes a core portion 22Aa and a coil portion 22Ab wound around the outer peripheral portion of the core portion 22Aa.

The third bending electromagnet 22B is provided downstream of the first bending electromagnet 21 in the traveling direction of the charged particle beam B so as to be adjacent to the first bending electromagnet 21, and the charged particle beam incident from the first bending electromagnet 21 B is the electromagnet that deflects. The third bending electromagnet 22B is provided diagonally below the first bending electromagnet 21 at a position on the positive side in the X-axis direction. The third bending electromagnet 22</b>B bends the charged particle beam B incident from the first bending electromagnet 21 in an arc shape so as to project downward, and then emits the bent beam toward the mounting section 4 .

When viewed from the Y-axis direction, the third bending electromagnet 22B has a substantially fan-like shape. The third bending electromagnet 22B has a shape line-symmetrical with the second bending electromagnet 22A with respect to the base axis AX. The third bending electromagnet 22B has an arc-shaped side surface 33B (fifth side surface) having a shape corresponding to the side surface 32B. The charged particle beam B from the first bending electromagnet 21 is incident on the third bending electromagnet 22B with the side surface 33B as an incident surface. The third bending electromagnet 22B has an arc-shaped side surface 34B (sixth side surface) that is line-symmetrical with the side surface 33B with respect to the reference line CL1. The charged particle beam B deflected within the third bending electromagnet 22B is emitted from the third bending electromagnet 22B with the side surface 34B as an emission surface. In addition, the third bending electromagnet 22B has a side surface 36B having a semi-arc shape convex downward between the lower end of the side surface 33B and the lower end of the side surface 34B. The third bending electromagnet 22B includes a core portion 22Ba and a coil portion 22Bb wound around the outer peripheral portion of the core portion 22Ba.

As shown in FIG. 2A, the pair of second bending electromagnets 22A and the pair of third bending electromagnets 22B are arranged so as to be separated from each other in the Y-axis direction. Thereby, a space SP2 is formed between the pair of second bending electromagnets 22A and between the pair of third bending electromagnets 22B. The pair of second bending electromagnets 22A and the pair of third bending electromagnets 22B are supported by the wall 44 on the side opposite to the space SP2. Since the space SP2 is a space in which the charged particle beam B travels, it is evacuated. Also, the space SP2 communicates with the space SP1.

As shown in FIG. 2, when the first bending electromagnet 21 deflects the charged particle beam B upward, the direction of the magnetic field in the space SP1 (indicated by the arrow in the drawing) is the positive side of the Y-axis direction. . Also, the direction of the magnetic field within the space SP2 by the second bending electromagnet 22A is the negative side of the Y-axis direction. On the other hand, when the first bending electromagnet 21 deflects the charged particle beam B downward, the direction of the magnetic field in the space SP1 is the positive side of the Y-axis direction. Also, the direction of the magnetic field within the space SP2 by the third bending electromagnet 22B is the positive side of the Y-axis direction.

As shown in FIG. 1, a side surface 34A of the second bending electromagnet 22A and a side surface 34B of the third bending electromagnet 22B function as exit surfaces for the charged particle beam B. As shown in FIG. Therefore, the irradiation section 3 includes the irradiation nozzle 7 between the side surfaces 34A, 34B and the mounting section 4. As shown in FIG. Various components such as a scanning electromagnet (when irradiation is performed by a scanning method), a quadrupole electromagnet, a monitor, and a degrader may be accommodated in the irradiation nozzle 7 . The irradiation unit 3 can adjust the emission positions of the charged particle beams B on the side surfaces 34A and 34B. Therefore, the irradiation nozzle 7 can be moved according to the emission position. Here, as described above, the spaces SP1 and SP2 (see FIG. 2) in which the charged particle beam B travels are kept in vacuum. Therefore, the spaces in which the bending electromagnets 21, 22A, and 22B are arranged are hermetically sealed from the external space in which the placement section 4 is arranged.

For example, as shown in FIG. 3, the space in which the bending electromagnets 21, 22A, and 22B are arranged is sealed by a wall portion 47 from the external space in which the mounting portion 4 is arranged. Here, the wall portion 47 includes a curved portion 47a that curves in an arc shape along the side surfaces 34A and 34B, a floor portion 47b that spreads horizontally at the same height as the floor surface F1 on which the mounting portion 4 is provided, It includes a lower wall portion 47c extending downward from the floor portion 47b along a stepped surface F2 extending downward from the floor surface F1, and an upper wall portion 47d extending upward from the curved portion 47a. The curved portion 47a is provided with the irradiation nozzle 7 in an airtight state.

Here, the irradiation nozzle 7 must move following the emission position of the charged particle beam B while maintaining the airtightness of the wall portion 47 . Therefore, when the irradiation nozzle 7 moves along the side surfaces 34A and 34B, it moves together with the wall portion 47 . That is, the portion of the wall portion 47 that was the curved portion 47a may become the floor portion 47b or the lower wall portion 47c as the irradiation nozzle 7 moves downward. For this reason, the wall portion 47 has a folding portion 47 e as a moving allowance for moving in accordance with the irradiation nozzle 7 . The folded portion 47e is a portion where the members forming the wall portion 47 are folded multiple times. The folding portion 47e is provided on the upper wall portion 47d. A portion of the folded portion 47e is stretched downward when the irradiation nozzle 7 moves downward.

The placement section 4 is provided on the downstream side of the second bending electromagnet 22A and the third bending electromagnet 22B in the traveling direction of the charged particle beam B, and is a section on which the patient W is placed. The placement unit 4 includes a treatment table 51 and a position adjustment mechanism 52 capable of adjusting the position of the treatment table 51 . The placement unit 4 is aligned so that the affected area of the patient W is positioned at the irradiation point RP. The irradiation point RP is the target position of the charged particle beam B irradiation. The irradiation point RP is set at the center point of the side surfaces 34A, 34B.

Next, the configurations of the first bending electromagnet 21, the second bending electromagnet 22A and the third bending electromagnet 22B will be described in more detail. It should be noted that the following description of the shape is for the shape when viewed from the negative side in the Y-axis direction to the positive side. First, referring to FIG. 4, the shapes of the first bending electromagnet 21 and the second bending electromagnet 22A will be described. Since the configuration of the bending electromagnets of the irradiation unit 3 is vertically symmetrical with respect to the basic axis AX, only the configuration above the basic axis AX is shown in FIG.

First, a virtual circle CR1 having a center point CP1 on the base axis AX is set. Of the first intersection point P1 on the upstream side and the second intersection point P2 on the downstream side between the circle CR1 and the base axis AX, the incident point IP of the charged particle beam B with respect to the first bending electromagnet 21 is at the position of the first intersection point P1. set. Also, the vertex TP of the first bending electromagnet 21 is set at the position of the second intersection point P2. A line perpendicular to the base axis AX and passing through the center point CP1 is defined as a reference line CL2, and a line passing through the incident point IP is defined as a reference line CL3. At the position of the reference line CL3, the side surface 31 extends upward from the incident point IP. The height of side 31 is the same as the radius of circle CR1.

The first bending electromagnet 21 has an arcuate side surface 32A in a portion within a range of 90° from the second intersection point P2 toward the first intersection point P1 in the upper arc of the circle CR1. A lower end portion of the side surface 32A corresponds to the vertex TP (second intersection point P2). The upper end of the side surface 32A corresponds to the third intersection point P3 between the circle CR1 and the reference line CL2. The first bending electromagnet 21 also has a plane 35 extending in the X-axis direction between the upper end 31a of the side surface 31 and the third intersection point P3.

The second bending electromagnet 22A is arranged in a region on the outer peripheral side of the side surface 32A of the first bending electromagnet 21 . The second bending electromagnet 22A has an arc-shaped side surface 33A having a shape corresponding to the side surface 32A, as described above. A lower end portion of the side surface 33A corresponds to the vertex TP, and an upper end portion of the side surface 33A corresponds to the third intersection point P3. The second bending electromagnet 22A has an arc-shaped side surface 34A that is line-symmetrical with the side surface 33A with respect to the reference line CL1. A lower end portion of the side surface 34A corresponds to the vertex TP, and an upper end portion of the side surface 34A corresponds to a line-symmetrical point P4 with respect to the third intersection point P3 and the reference line CL1. When the intersection of the reference line CL4 connecting the points P3 and P4 and the reference line CL1 is set as the center point CP2, the side surface 36A is an arc centered on the center point CP2 and passing through the points P3 and P4.

Next, behavior of the charged particle beam B in the irradiation unit 3 will be described. As shown in FIG. 5, the deflection angle of the first bending electromagnet 21 is defined as a first deflection angle θ1. A point P10, which is an emission point of the charged particle beam B on the side surface 32A at this time, is set on a normal line NL1 that passes through the center point CP1 of the side surface 32A and forms a first deflection angle θ1 with respect to the base axis AX. be. Since the charged particle beam B moves in a circular arc in a constant magnetic field, the charged particle beam B is perpendicularly incident on the side surface 31 at the incident point IP within the first bending electromagnet 21, The light is emitted perpendicular to the side surface 32A at the point P10 (perpendicular to the tangent line TL1 to the point P10). Therefore, the center point CP3 of the arc trajectory of the charged particle beam B is set at the intersection of the reference line CL3 and the tangent line TL1. That is, the deflection radius for deflecting the charged particle beam B at the first deflection angle θ1 is obtained from the distance between the center point CP3 and the incident point IP.

A point P10 is an emission point of the first bending electromagnet 21 and an incidence point of the second bending electromagnet 22A. Therefore, the normal line NL1 passing through the point P10 serves as a reference for the incident charged particle beam B. FIG. The deflection angle of the second bending electromagnet 22A is defined as a second deflection angle θ2. The second deflection angle θ2 is the angle of the charged particle beam B that exits the second bending electromagnet 22A with respect to the charged particle beam B that has entered the second bending electromagnet 22A. Here, the side surface 34A has a line-symmetrical relationship with the side surface 33A. Therefore, a point P11 that is symmetrical with the point P10 with respect to the reference line CL1 is the exit point of the side surface 34A. The charged particle beam B is emitted perpendicularly from the side surface 34A, which is the emission surface, at a point P11. Also, the normal line NL2 passing through the point P11 serves as a reference for the emitted charged particle beam B. As shown in FIG. Normal NL1 and normal NL2 intersect at center point CP2. The angle of the normal NL2 with respect to the normal NL1 is the second deflection angle θ2 of the second bending electromagnet 22A. The second deflection angle θ2 is an angle toward the opposite side of the first deflection angle θ1. The charged particle beam B emitted from the point P11 travels toward the irradiation point RP along the normal line NL2. Therefore, the angle of the normal NL2 with respect to the base axis AX is the illumination angle θ3.

The arc of the side surface 33A and the arc of the side surface 34A have a line-symmetrical relationship with respect to the reference line CL1. Therefore, the distance from the center point CP1 to the center point CP2 is equal to the distance from the irradiation point RP to the center point CP2. That is, the triangle formed by the center point CP1, the center point CP2, and the irradiation point RP is an isosceles triangle. Therefore, the second deflection angle .theta.2 is the sum of the first deflection angle .theta.1, which is the base angle, and the illumination angle .theta.3. The magnitude of the first deflection angle θ1, which is the base angle, and the magnitude of the irradiation angle θ3 are equal to each other. Therefore, the second deflection angle .theta.2 is twice as large as the first deflection angle .theta.1 and is directed to the opposite side of the first deflection angle .theta.1.

The center point CP4 of the arc trajectory of the charged particle beam B is set at the intersection of the reference line CL1 and the tangent line TL1. That is, the deflection radius for deflecting the charged particle beam B at the second deflection angle θ2 is obtained from the distance between the center point CP4 and the point P10.

Here, the deflection radius R is represented by the following formula (1). However, p indicates the momentum of the charged particle, q indicates the charge of the charged particle, and B indicates the magnetic flux density. Since the momentum p and the electric charge q are constant, the deflection radius R can be set to a desired value simply by adjusting the magnetic flux density B. Therefore, in order to deflect the charged particle beam B at the first deflection angle θ1 by the first bending electromagnet 21, The magnetic flux density B of the first bending electromagnet 21 is adjusted. Further, in order to deflect the charged particle beam B at the second deflection angle θ2 by the second bending electromagnet 22A, the first 2 Adjust the magnetic flux density B of the bending electromagnet 22A.

R=p/qB (1)

Also, as shown in FIG. 6, when the irradiation angle .theta.3 is desired to be larger than that shown in FIG. 5, the first deflection angle .theta.1 is increased. In this case, since the charged particle beam B draws a small arc within the first bending electromagnet 21, the magnetic flux density of the first bending electromagnet 21 is adjusted to be higher than that shown in FIG. Further, since the charged particle beam B draws a large arc in the second bending electromagnet 22A, the magnetic flux density of the second bending electromagnet 22A is adjusted to be smaller than that shown in FIG. Thus, by adjusting the magnetic flux densities of the bending electromagnets 21 and 22A, the patient W can be irradiated with the charged particle beam B at the desired irradiation angle θ3.

4 to 6, the description has been given on the premise that a uniform magnetic field is generated even in the vicinity of the boundary between bending electromagnets. However, as shown in FIGS. 1 and 2, it may not always be possible to generate a uniform magnetic field by arranging a coil or the like near the boundary between bending electromagnets. In such a case, the magnetic field intensity of the angular bending electromagnet is adjusted according to the situation at the boundary.

Next, the actions and effects of the charged particle beam therapy system 1 of this embodiment will be described.

A charged particle beam therapy apparatus 1 according to the present embodiment is a charged particle beam therapy apparatus 1 that irradiates a patient W with a charged particle beam B. a first bending electromagnet 21 that is deflected at a deflection angle θ1; a second bending electromagnet 22A that deflects the charged particle beam B incident from the second bending electromagnet 22A at a second deflection angle θ2; And prepare. The second deflection angle .theta.2 is twice as large as the first deflection angle .theta.1 and directed to the side opposite to the first deflection angle .theta.1.

The charged particle beam therapy apparatus 1 includes a first deflection electromagnet 21 that deflects the charged particle beam B incident from the accelerator 2 side at a first deflection angle θ1 corresponding to energy, and a first deflection magnet 21 that deflects the charged particle beam B in the traveling direction of the charged particle beam B A second bending electromagnet 22A is provided downstream of the electromagnet 21 so as to be adjacent to the first bending electromagnet 21, and deflects the charged particle beam B incident from the first bending electromagnet 21 at a second deflection angle θ2. . As a result, the charged particle beam B from the accelerator 2 side is deflected by the first bending electromagnet 21 and deflected by the second bending electromagnet 22A, and then irradiated to the patient W placed on the placement section 4. Here, when the deflection angle of the first bending electromagnet 21 is the first deflection angle θ1 and the deflection angle of the second bending electromagnet 22A is the second deflection angle θ2, the second deflection angle θ2 of the second bending electromagnet 22A is The angle is twice as large as the first deflection angle .theta.1 and directed to the side opposite to the first deflection angle .theta.1. Thereby, the second bending electromagnet 22A can irradiate the patient W with the charged particle beam B at the irradiation angle θ3 that is the same as the first deflection angle θ1. Because of such a simple relationship, it is possible to irradiate the patient W with the charged particle beam B at the desired irradiation angle θ3 simply by adjusting the magnetic field strength of the first bending magnet 21 and the second bending magnet 22A. . Also, the irradiation angle θ3 of the charged particle beam B with respect to the patient W can be adjusted by using the first bending electromagnet 21 and the second bending electromagnet 22A adjacent to each other without using a large number of bending electromagnets. Therefore, the charged particle beam therapy system 1 can be reduced in size in the height direction compared to a rotating gantry type system, and the footprint can be reduced compared to the case where a large number of bending electromagnets are used. can be done. As described above, it is possible to provide the charged particle beam therapy apparatus 1 that can be miniaturized.

The first bending electromagnet 21 sets a virtual circle CR1 having a center point CP1 on the base axis AX of the charged particle beam B incident from the accelerator 2 side, and a first intersection point P1 on the upstream side between the circle CR1 and the base axis AX. and the second intersection point P2 on the downstream side, the incident point IP of the charged particle beam B is at the position of the first intersection point P1. The second bending electromagnet 22A is arranged in an area on the outer peripheral side of the side surface 32A of the first bending electromagnet 21, and is viewed from the lateral direction. , an arc-shaped side surface 33A having a shape corresponding to that of the side surface 32A, and a line symmetry with the side surface 33A with respect to a reference line CL1 that is perpendicular to the base axis AX and passes through the second intersection point P2 when viewed from the lateral direction. and an arcuate side surface 34A. In such a configuration, the first bending electromagnet 21 deflects the charged particle beam B incident from the incident point IP and emits it from any position on the side surface 32 . The charged particle beam B emitted from the side surface 32A is immediately incident on the second bending electromagnet 22A from the side surface 33A. At this time, the side surface 33A has a shape corresponding to the arcuate side surface 32A. Moreover, the side surface 34A has an arcuate shape that is symmetrical with the side surface 33A with respect to the reference line CL1. Therefore, the charged particle beam B draws a line-symmetric orbit with respect to the reference line CL1 in the second bending electromagnet 22A, and emerges from the side surface 34A in a line-symmetrical manner with respect to the incident state on the side surface 33A.

The charged particle beam therapy apparatus 1 of this embodiment is a charged particle beam therapy apparatus 1 that irradiates a patient W with a charged particle beam B, and deflects the charged particle beam B incident from the accelerator 2 side according to energy. 1 bending electromagnet 21 and the charged particle beam B incident from the first bending electromagnet 21 are provided on the downstream side of the first bending electromagnet 21 so as to be adjacent to the first bending electromagnet 21 in the traveling direction of the charged particle beam B. and a placement section 4 on which the patient W is placed, provided downstream of the second bending electromagnet 22A in the traveling direction. A virtual circle having a center point CP1 on the base axis AX of the charged particle beam B incident from the second side is set, and a first intersection point P1 on the upstream side and a second intersection point P2 on the downstream side of the circle CR1 and the base axis AX are defined. Among them, the incident point IP of the charged particle beam B is at the position of the first intersection point P1, and at least one of the arcs on the upper side of the circle CR1 has a range of 90° from the second intersection point P2 toward the first intersection point P1. The second bending electromagnet 22A is arranged in an area on the outer peripheral side of the side surface 32A of the first bending electromagnet 21, and has a shape corresponding to the side surface 32A when viewed from the lateral direction. It has an arcuate side surface 33A and an arcuate side surface 34A that is linearly symmetrical with the side surface 33A with respect to the reference line CL1 that is perpendicular to the base axis AX and passes through the second intersection point P2 when viewed from the lateral direction. .

The charged particle beam therapy apparatus 1 includes a first bending electromagnet 21 that deflects the charged particle beam B incident from the accelerator 2 side in accordance with energy, and a first bending electromagnet 21 downstream of the first bending electromagnet 21 in the traveling direction of the charged particle beam B. A second bending electromagnet 22</b>A is provided adjacent to the first bending electromagnet 21 and deflects the charged particle beam B incident from the first bending electromagnet 21 . As a result, the charged particle beam B from the accelerator 2 side is deflected by the first bending electromagnet 21 and deflected by the second bending electromagnet 22A, and then irradiated to the patient W placed on the placement section 4. Here, the first bending electromagnet 21 deflects the charged particle beam B incident from the incident point IP and emits it from any position on the side surface 32A. The charged particle beam B emitted from the side surface 32A is immediately incident on the second bending electromagnet 22A from the side surface 33A. At this time, the side surface 33A has a shape corresponding to the arcuate side surface 32A. Moreover, the side surface 34A has an arcuate shape that is symmetrical with the side surface 33A with respect to the reference line CL1. Therefore, the charged particle beam B draws a line-symmetric orbit with respect to the reference line CL1 in the second bending electromagnet 22A, and emerges from the side surface 34A in a line-symmetrical manner with respect to the incident state on the side surface 33A. Because of such a simple relationship, it is possible to B-irradiate the patient W with the charged particle beam at the desired irradiation angle θ3 simply by adjusting the magnetic field strength of the first bending magnet 21 and the second bending magnet 22A. . Also, the irradiation angle θ3 of the charged particle beam B with respect to the patient W can be adjusted by using the first bending electromagnet 21 and the second bending electromagnet 22A adjacent to each other without using a large number of bending electromagnets. Therefore, the charged particle beam therapy system 1 can be reduced in size in the height direction compared to a rotating gantry type system, and the footprint can be reduced compared to the case where a large number of bending electromagnets are used. can be done. As described above, it is possible to provide the charged particle beam therapy apparatus 1 that can be miniaturized.

The charged particle beam therapy apparatus 1 is provided on the downstream side of the first bending electromagnet 21 in the traveling direction of the charged particle beam B so as to be adjacent to the first bending electromagnet 21 . A third bending electromagnet 22B for deflecting the line B is further provided. The first bending electromagnet 21 has an arcuate side surface 32B in at least one portion of the lower arc of the circle CR1 within a range of 90° from the second intersection point P2 toward the first intersection point P1. , The third bending electromagnet 22B is arranged in an area on the outer peripheral side of the side surface 32B of the first bending electromagnet 21, and has an arc-shaped side surface 33B having a shape corresponding to the side surface 32B when viewed from the lateral direction, and an arc-shaped side surface 33B having a shape corresponding to the side surface 32B when viewed from the lateral direction. may have an arcuate side surface 34B that is symmetrical with the side surface 32B with respect to a reference line CL1 that is perpendicular to the base axis AX and passes through the second intersection point P2. According to such a configuration, it is possible to irradiate the patient W with the charged particle beam B from below at a desired irradiation angle θ3 by using the third bending electromagnet 22B.

The second deflection angle .theta.2 by the second bending electromagnet 22A is twice the first deflection angle .theta.1 by the first bending electromagnet 21 and is directed to the opposite side of the first deflection angle .theta.1. Thereby, the second bending electromagnet 22A can irradiate the patient W with the charged particle beam B at the irradiation angle θ3 that is the same as the first deflection angle θ1.

The invention is not limited to the embodiments described above.

For example, in the above-described embodiment, the bending electromagnets 22A and 22B have arc-shaped side surfaces 33A and 33B over the entire range of 90° from the second intersection point P2 toward the first intersection point P1. Alternatively, there may be a portion in the range of 0° to 90° that does not extend arcuately. For example, a part of the area near the second intersection point P2 and a part of the area near 90° may not be arcuate. Alternatively, the arc-shaped side surfaces 33A and 33B may extend not only to the range of 90° from the second intersection P2, but also to the portion on the first intersection P1 side of 90°.

Moreover, the irradiation unit 3 only needs to include at least the second bending electromagnet 22A, and the third bending electromagnet 22B may be omitted.

The shape of the region of the first bending electromagnet 21 on the negative side of the reference line CL2 in the X-axis direction may be any shape as long as the trajectory of the charged particle beam B is not affected. Moreover, the shape of the portions of the bending electromagnets 22A and 22B other than the side surfaces 33A, 33B, 34A and 34B may be any shape as long as the trajectory of the charged particle beam B is not affected. For example, the side surface 36A is arc-shaped, but may be rectangular or the like.

DESCRIPTION OF SYMBOLS 1... Charged particle beam therapy apparatus 4... Placement part 21... First bending electromagnet 22A... Second bending electromagnet 22B... Third bending electromagnet 32A... Side surface (first side surface) 32B... Side surface (fourth side surface) Side), 33A... Side (second side), 33B... Side (fifth side), 34A... Side (third side), 34B... Side (sixth side), B... Charged particle beam.

Claims (5)

A charged particle beam therapy apparatus for irradiating a body to be irradiated with a charged particle beam,
a first bending electromagnet that deflects the charged particle beam incident from the accelerator side at a first deflection angle according to the kinetic energy of the charged particle beam ;
provided so as to be adjacent to the first bending electromagnet on the downstream side of the first bending electromagnet in the traveling direction of the charged particle beam, and deflect the charged particle beam incident from the first bending electromagnet at a second deflection angle; a second bending electromagnet that
a mounting section provided downstream of the second bending electromagnet in the direction of travel and on which the object to be irradiated is mounted;
The charged particle beam therapy apparatus, wherein the second deflection angle is twice as large as the first deflection angle and directed to the side opposite to the first deflection angle. The first bending electromagnet is
A virtual circle having a center point on the base axis of the charged particle beam incident from the accelerator side is set, and out of a first intersection point on the upstream side and a second intersection point on the downstream side between the circle and the base axis, the Having an incident point of the charged particle beam at the position of the first intersection,
having an arc-shaped first side surface in at least any portion of the upper arc of the circle within a range of 90° from the second intersection point toward the first intersection point;
The second bending electromagnet is arranged in an area on the outer peripheral side of the first side surface of the first bending electromagnet,
an arc-shaped second side surface having a shape corresponding to the first side surface when viewed from the lateral direction;
2. An arcuate third side surface line-symmetrical to said second side surface with respect to a reference line perpendicular to said base axis and passing through said second intersection when viewed from said lateral direction. The charged particle beam therapy system according to . A charged particle beam therapy apparatus for irradiating a body to be irradiated with a charged particle beam,
a first bending electromagnet that deflects the charged particle beam incident from the accelerator side according to the kinetic energy of the charged particle beam ;
A second bending electromagnet provided adjacent to the first bending electromagnet on the downstream side of the first bending electromagnet in the traveling direction of the charged particle beam, and deflecting the charged particle beam incident from the first bending electromagnet. When,
a mounting section provided downstream of the second bending electromagnet in the direction of travel and on which the object to be irradiated is mounted;
The first bending electromagnet is
A virtual circle having a center point on the base axis of the charged particle beam incident from the accelerator side is set, and out of a first intersection point on the upstream side and a second intersection point on the downstream side between the circle and the base axis, the Having an incident point of the charged particle beam at the position of the first intersection,
having an arc-shaped first side surface in at least any portion of the upper arc of the circle within a range of 90° from the second intersection point toward the first intersection point;
The second bending electromagnet is arranged in an area on the outer peripheral side of the first side surface of the first bending electromagnet,
an arc-shaped second side surface having a shape corresponding to the first side surface when viewed from the lateral direction;
an arc-shaped third side surface that is symmetrical with the second side surface with respect to a reference line that is perpendicular to the base axis and passes through the second intersection when viewed from the lateral direction; therapeutic device. a third bending electromagnet provided downstream of the first bending electromagnet in the traveling direction of the charged particle beam so as to be adjacent to the first bending electromagnet for deflecting the charged particle beam incident from the first bending electromagnet; further comprising
the first bending electromagnet has an arc-shaped fourth side surface on at least one portion of the lower arc of the circle within a range of 90° from the second intersection point toward the first intersection point;
The third bending electromagnet is arranged in an area on the outer peripheral side of the fourth side surface of the first bending electromagnet,
an arc-shaped fifth side surface having a shape corresponding to the fourth side surface when viewed from the lateral direction;
4. An arcuate sixth side surface that is symmetrical with the fourth side surface with respect to a reference line that is perpendicular to the base axis and passes through the second intersection when viewed from the lateral direction. The charged particle beam therapy system according to . 5. The second deflection angle according to claim 3 or 4, wherein the second deflection angle by the second bending magnet is twice as large as the first deflection angle by the first bending electromagnet and is directed to the opposite side of the first deflection angle. charged particle beam therapy system.

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