JPH10300899A - Radiation therapeutic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dose distribution satisfactory even to a wide range emitting field by generating a rotating magnetic field on the orbit of a charged particle beam, generating also the other reverse directional rotating magnetic field, and rotating and scanning the charged particle beam by the other rotating magnetic field. SOLUTION: Scanning means 52, 53 are formed of, for example, quadrupole electromagnets, and they are worked as wobbler electromagnets magnets for performing a circulatory scanning with charged particle beams by supplying sine wave ac currents phase-controlled so as to generate mutually reverse directional rotating magnetic fields, respectively. A charged particle beam 1 is accelerated by an accelerator and incident on the scanning means 52. The scanning means 52 rotates and scans in the radial direction by the rotating magnetic field, and the charged particle beam 1 is conically extended and incident on the scanning means 53. The scanning means 53 rotates and scans in the beam axial direction by the reverse directional magnetic field, the charged particle beam 1 is focused in reverse conical form, incident on one point of a scattered body 3, and scattered with the incident point as the focus, and the dose is detected by a dose monitor 5. According to this method, the charged particle beam 1 can be emitted while suppressing the influence by half shadow by making the incident point into a point shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiotherapy apparatus for treating a malignant tumor or the like generated in an affected part by selectively irradiating a charged particle beam.

[0002]

2. Description of the Related Art In general, a radiotherapy apparatus has a gantry section rotatably supported around a treatment table, and is a beam-shaped charged particle beam accelerated by an accelerator constituted by an acceleration tube or the like (hereinafter referred to as a charged particle beam). ) Is irradiated from below the gantry to an irradiated part, for example, a treatment affected part of a patient, to treat a malignant tumor such as cancer generated in the affected part. In addition, the charged particle beam irradiated to the affected part forms a dose distribution that is uniform and has no penumbra on the beam irradiation surface, from the viewpoint of safety and treatment efficiency for a patient to which the charged particle beam is transmitted. It is desirable. For example, 5-4047
No. 9 (Japanese Utility Model Application No. 62-153326) discloses an X-direction scanning electromagnet (3) for deflecting the charged particle beam (1) in the X direction and a Y-direction scanning electromagnet (4) for deflecting the charged particle beam (1) in the Y direction.
The wobble electromagnet composed of
A scanning electromagnet that rotates and scans the charged particle beam in a circular shape is called a wobble electromagnet. ), A charged particle beam apparatus that scatters a charged particle beam (1) rotationally scanned by combining these two types of scanning electromagnets with a scatterer (6) made of a lead plate and irradiates a wide range of irradiation surface. Have been.

[0003]

The conventional radiotherapy apparatus is configured as described above, and two types of charged particle beams accelerated by an accelerator or the like are arranged so as to overlap on the beam trajectory of the charged particle beam. Are scanned in a circular shape by the rotating magnetic field generated from the scanning electromagnets (X-direction scanning electromagnet and Y-direction scanning electromagnet), so that the charged particle beam that passes through the collimator and irradiates the irradiation surface is X
Due to the positional relationship between the directional scanning electromagnet and the Y-direction scanning electromagnet, there is a problem that the rotational symmetry is poor (not accurate circular shape). Actually, in order to realize the rotation scanning of the charged particle beam having good rotational symmetry by the above conventional radiotherapy apparatus, the scanning electron magnets (X-direction and Y-direction scanning electromagnets) are supplied with each other to generate a magnetic flux density. It is necessary for a device administrator such as a radiologist to make fine adjustments appropriately to the current value of the control current for controlling the direction according to the shape, size, etc. of the treatment affected part. It was a heavy burden and also caused a prolonged treatment time.

A charged particle beam rotationally scanned by the above-described conventional radiation therapy apparatus is incident on a scatterer while being spread in a conical shape, and passes through the scatterer to irradiate an irradiation surface. The charged particle beam does not have a point-like (one point) focal point, and the irradiated surface of the affected part or the like is irradiated with the penetrated charged particle beam. FIG.
FIG. 17 is a beam trajectory explanatory diagram showing a beam trajectory of a charged particle beam by a conventional radiotherapy apparatus and a dose distribution of the charged particle beam formed on the irradiation surface by the charged particle beam. FIG. The principle on which penumbra occurs in the dose distribution will be described. In FIG. 17, 1
00 is a charged particle beam accelerated in the direction of the arrow from a radiation source (not shown), 101 is an X-direction scanning electromagnet, 102 is a Y-direction scanning electromagnet, 103 is a scatterer, and 104 is the beam shape of the charged particle beam according to the shape of the irradiation surface. And 105, an isocenter located on the irradiation surface of the charged particle beam.

[0005] As shown in FIG.
06 is an X-direction scanning electromagnet 101 and a Y-direction scanning electromagnet 1
The charged particle beam 100 rotated and scanned by the wobble electromagnet 106 is a beam orbit axis 10
The light is expanded conically around the center 7 and is incident on the scatterer 103. FIG. 16 shows the state of scattering of only two types of charged particle beams 110 and 111 having the two incident points 108 and 109 of the scatterer 103 as focal points. The charged particle beam 100 that has been rotationally scanned in a conical shape is incident on 103, and actually forms a circular focal point in the scatterer 103. The charged particle beam 100 rotated and scanned by the wobble electromagnet 106 has its beam radius expanded by the scatterer 103, so that the charged particle beam irradiated on the irradiation surface forms a normal distribution in a wide range, and FIG. A dose distribution 112 as shown is formed. However, scatterer 1
Since the charged particle beam 100 rotated and scanned by the wobbler electromagnet 106 is incident on the scatterer 103,
Are scattered from a plurality of focal points (only 108 and 109 are shown in FIG. 16).
Even if the shape of the laser beam 04 is set to a shape corresponding to the irradiation surface, the charged particle beam is irradiated to the shifted position on the irradiation surface, and the end of the dose distribution 112 ( At the edge portion 113, a phenomenon called penumbra occurs in which the dose gradually changes as shown in FIG.

As shown in FIG. 16, a phenomenon in which the dose distribution edge of the charged particle beam changes gently with respect to the irradiation surface is called a penumbra, and the charged particle beam having such a penumbra is generated. Is irradiated to the affected part, the irradiated surface is irradiated with a charged particle beam slightly different from the actual shape set in the collimator 104, and when the beam shape is set to the maximum, The charged particle beam scattered by the scatterer 103 is irradiated to the normal cell tissue other than the affected part, and the collimator 1 is used in consideration of safety.
If the shape of 04 is set smaller than the actual shape of the affected part, the charged particle beam may be irradiated more than necessary, such as irradiating multiple charged particle beams many times. There is a big problem from the viewpoint of safety in the radiotherapy apparatus to be treated. The work of irradiating the charged particle beam by selecting the irradiation range many times requires time and labor for positioning the irradiation position, etc.
As described above, it is a great burden for the device administrator.

FIG. 17 is a dose distribution diagram showing an ideal dose distribution state of the charged particle beam. If the charged particle beam has a dose distribution as shown in FIG. While it can be set to the maximum, the irradiation of the charged particle beam to areas other than the affected area can be sufficiently prevented, eliminating the need to select the irradiation area multiple times, greatly improving the treatment efficiency and charging the areas other than the irradiation area. Irradiation of a particle beam can be easily prevented, and safety to a human body by radiation therapy can be greatly improved.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a radiotherapy apparatus capable of irradiating a charged particle beam having a good dose distribution to a wide range of irradiation fields. It is an object of the present invention to provide a radiation therapy apparatus having a novel configuration in which the rotationally scanned charged particle beam has good rotational symmetry and can maintain good rotational symmetry regardless of the change in the degree of deflection of the charged particle beam. In addition, we suppress penumbra generated in charged particle beam by rotation scan,
Radiation therapy with a novel configuration that can form a charged particle beam with a dose distribution that is safe and has good irradiation efficiency with the maximum beam shape of the charged particle beam to the affected area such as a tumor and preventing irradiation of normal cell tissue The aim is to obtain a device.

[0009]

According to a first aspect of the present invention, there is provided a radiotherapy apparatus comprising: a scatterer provided on a trajectory of a charged particle beam; and a dose of the charged particle beam scattered by the scatterer. A dose monitor to be detected, a collimator that changes the beam shape of the charged particle beam scattered by the scatterer according to the shape of the irradiated object, and a trajectory of the charged particle beam provided on the trajectory of the charged particle beam A first scanning means for generating a first rotating magnetic field, and a second rotating magnetic field which is provided on a trajectory of the charged particle beam and has a direction opposite to the first rotating magnetic field. And a second scanning means for rotatingly scanning the charged particle beam by the rotating magnetic field.

According to a second aspect of the present invention, the first and second scanning means are arranged upstream of the scatterer.

According to a third aspect of the present invention, in the radiation therapy apparatus, the scanning means is constituted by a multi-pole electromagnet having the same pole formed between opposed magnetic pole cores.

According to a fourth aspect of the present invention, there is provided a radiotherapy apparatus comprising: a range shifter provided on a trajectory of a charged particle beam;
The range shifter is composed of a collimator that changes the beam shape of the charged particle beam whose irradiation energy is adjusted according to the shape of the irradiation target, and a quadrupole electromagnet in which the same pole is formed between opposed magnetic pole cores, and has a 90 deg phase. Scanning means for generating a rotating magnetic field on the trajectory of the charged particle beam in the upstream part of the range shifter by applying two kinds of alternating currents different from each other.

According to a fifth aspect of the present invention, there is provided a radiation therapy apparatus, wherein a range shifter provided on a trajectory of a charged particle beam;
A collimator that changes the beam shape of the charged particle beam whose irradiation energy is adjusted by the range shifter in accordance with the shape of the irradiation target, and a six-pole electromagnet in which the same pole is formed between opposed magnetic pole cores, Scanning means for generating a rotating magnetic field on the trajectory of the charged particle beam in the upstream part of the range shifter by applying three types of alternating currents whose phases are shifted by 60 degrees.

According to a sixth aspect of the present invention, there is provided a radiation therapy apparatus comprising: a scatterer provided on a trajectory of a charged particle beam; a dose monitor for detecting a dose of the charged particle beam scattered by the scatterer; A range shifter that changes the irradiation energy of the charged particle beam based on the dose detected by the dose monitor; and a collimator that changes the beam shape of the charged particle beam whose irradiation energy is adjusted by the range shifter according to the shape of the irradiation target. And a first scanning means for generating a rotating magnetic field on the trajectory of the charged particle beam, comprising: a multi-pole electromagnet having the same pole formed between the opposed magnetic pole cores; Are formed, and a second rotating magnetic field in a direction opposite to the first rotating magnetic field is generated, and the charged particle beam is generated by the second rotating magnetic field. It is provided with a second scanning means for rotating the scan.

According to a seventh aspect of the present invention, there is provided a radiotherapy apparatus, wherein a second collimator is provided between the scatterer and the dose monitor and shields a charged particle beam incident outside the irradiation field. Things.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment. 1 An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an embodiment of the present invention, and is a schematic configuration diagram schematically showing a radiotherapy apparatus according to the present invention. FIG. 2 is a scanning unit used in the radiotherapy apparatus of FIG. FIG. 2A and FIG. 2B are a perspective projection view and a cross-sectional configuration view of a scanning unit, respectively.
FIG. 3 is a treatment explanatory view schematically showing a general treatment situation by the radiation treatment apparatus. Hereinafter, in the description of the radiotherapy apparatus according to the present invention, the term "upstream" means closer to the radiation source, and the term "downstream" means closer to the irradiation surface remote from the radiation source. 1 and 2, reference numeral 1 denotes a pencil particle-shaped charged particle beam (hereinafter, referred to as a charged particle beam) generated from a radiation source (not shown) and accelerated by an accelerator or the like, and 2 denotes a radiation therapy apparatus according to the present embodiment. The scanning means is a quadrupole electromagnet having first to fourth magnetic poles, and the charged particle beam 1 rotated and scanned by the scanning means 2 is incident on the quadrupole electromagnet 3, and the charged particle beam 1 is focused on the incident point as a cone ( The scatterer 4 scattered in a cone shape detects the dose of the charged particle beam 1 scattered in a cone shape,
The dose monitor chamber 5 for generating a control signal for controlling a range filter, a movable collimator, and the like, which will be described later, has an energy spectrum (dose distribution) in the depth direction adjusted by the thickness of the protruding portion. A ridge filter 7 having an energy spectrum corresponding to the thickness, a range filter 7 whose thickness in the beam traveling direction is adjusted, and a range filter for reducing a predetermined amount of energy of the charged particle beam 1 having passed by the set thickness, and 8 a unnecessary charge. A block collimator 9 for temporarily cutting particles is provided with a charged particle beam 9 for making the charged particle beam passing through the block collimator 8 correspond to the shape of the irradiation surface of the treatment target.
A movable collimator 9 for shaping the beam shape of the charged particle beam 1; an isocenter 1 indicating an irradiation position (irradiation surface) of the charged particle beam 1;
0 is a virtual beam orbit axis indicating the beam center line of the charged particle beam 1.

Reference numerals 11 to 14 denote magnetic pole cores (11) of the quadrupole electromagnet 2 in which the same pole is formed between a pair of opposing magnetic poles.
Denotes a first magnetic pole, 12 denotes a second magnetic pole, 13 denotes a third magnetic pole, and 14 denotes a fourth magnetic pole. ), 15a to 15d are wound around these magnetic pole cores 11, 12, 13, and 14, respectively, between the coils of the opposing magnetic pole cores (the first magnetic pole 11 and the third magnetic pole 11).
The coils 16 connected in series between the magnetic poles 13 and between the second magnetic pole 12 and the fourth magnetic pole 14 guide the magnetic flux by the magnetomotive force generated by the coils 15a to 15d wound around the magnetic cores 11 to 14. Yoke, 17 is yoke 1
6 is a magnetic flux density generated in the gap 18 by the magnetic flux guided by 6. The direction of the magnetic flux density 17 is determined by a sine wave alternating current described later applied to coils 15a to 15d wound around the magnetic pole cores 11 to 14, and is controlled by a phase control of the sine wave alternating current described later. The quadrupole electromagnet 2 acts as a wobble electromagnet (hereinafter, referred to as a wobble electromagnet).
A scanning electromagnet that rotates and scans the charged particle beam in a circular shape is called a wobble electromagnet. ).

In FIG. 3, reference numeral 19 denotes the above 2 to 9
A gantry section of a radiation therapy apparatus having the respective components inside,
Reference numeral 20 denotes an arm unit rotatably supported by the apparatus main body unit 21 and rotates the gantry unit 19, and 22 denotes a treatment table provided to be movable in the X and Y directions with respect to the support table 23. The gantry section 19 is placed on the affected part 24 of the patient on the treatment table 22 positioned at the position of the isocenter 9 by the movement of the gantry section 19 and the movement of the gantry section 19 and the arm section 20.
The charged particle beam 1 output from is irradiated. In addition,
In the radiotherapy apparatus as shown in FIG.
Is rotated around the treatment table 22 to irradiate the affected part 23 with radiation, so that if the gantry configuration can be reduced, the degree of freedom when moving around the treatment table in the same space can be increased. In radiotherapy equipment with complicated treatment operations such as three-dimensional irradiation type radiotherapy equipment,
From the viewpoint of improvement in operability, a reduction in the size of the gantry configuration is required.

Next, the operation of the radiotherapy apparatus shown in FIG. 1 and the specific operation of the quadrupole electromagnet 2 will be described in detail with reference to FIGS. FIG. 4 is a scanning means of the present embodiment, and is a coil current explanatory diagram showing a phase relationship between two kinds of sine wave AC currents respectively supplied to the quadrupole electromagnet 2 constituting the Wobble electromagnet, and FIG. a) to FIG. 5
(I) shows each phase point (0, 0) in the coil current explanatory diagram shown in FIG.
deg, 45 deg, 90 deg, 135 deg, 18
0 deg, 225 deg, 270 deg, 315 de
g, 360 deg) is a magnetic flux density explanatory diagram showing the magnetic flux density direction of each magnetic flux density generated in the gap 18 by the quadrupole electromagnet 2. In FIG. 4, the horizontal axis represents the phase (phase), and the vertical axis represents the current value (current) of the sine wave AC current at each phase point. In FIGS. 5 (a) to 5 (i), the first magnetic pole 11 Only the reference numerals are attached and the others are omitted.

In the description of the present embodiment, the first magnetic pole 1
A sine wave alternating current (0 deg) having an initial phase of 0 deg shown in FIG. 4 is applied to the coils 15 a and 15 b of the first and third magnetic poles 13, and the coils 15 a and 15 b of the second magnetic pole 12 and the fourth magnetic pole 14 are formed.
A sine wave AC current (90 deg) having an initial phase of 90 deg is applied to b and 15 d, respectively. A sine wave AC current (0 deg) applied to the coils 15 a and 15 b of the first magnetic pole 11 and the third magnetic pole 13 is assumed. The initial phase is shifted by 90 degrees from the sine wave alternating current (90 deg) applied to the coils 15b and 15d of the second magnetic pole 12 and the fourth magnetic pole 14, as shown in FIG.

First, a charged particle beam from a radiation source (not shown) is accelerated by an accelerator or the like and is incident on the scanning means 2. The scanning means 2 is supplied with a phase-controlled sine-wave alternating current described later, functions as a wobble electromagnet, and rotationally scans the charged particle beam 1 in a conical shape by a rotating magnetic field generated in the gap 18. Next, the charged particle beam 1 rotationally scanned by the scanning means 2 is incident on the scatterer 3 and scattered in a cone shape. After the dose is detected by the dose monitor 5, the ridge filter 6, the range filter 7, The beam passes through the block collimator 8 and the movable collimator 9 and is shaped into a beam shape corresponding to the shape of the irradiation surface, and is irradiated to the affected part (irradiation surface) positioned at the isocenter 10. As described above, according to the radiotherapy apparatus of the present embodiment, since a wobble electromagnet configured to rotate and scan a charged particle beam by one scanning electromagnet is configured, a conventional type in which two types of deflection electromagnets are arranged on a beam axis in an overlapping manner. In addition to the configuration in which the size of the beam traveling direction is shorter than that of the scanning means of the radiotherapy apparatus, the charged particle beam 1 is rotated in the same plane, so that the charged particle beam 1 is charged between two different planes including the X plane and the Y plane. It is possible to obtain a charged particle beam having better rotational symmetry as compared with a conventional radiation therapy apparatus that applies a rotating action to a particle beam.

Next, the specific operation of the quadrupole electromagnet 2 will be described. First, at the point of the phase 0 deg, the second
A +1 current sine wave alternating current is applied only between the coils 15b and 15d of the magnetic pole 12 and the fourth magnetic pole 14, and is not applied between the coils 15a and 15c of the first magnetic pole 11 and the third magnetic pole 13. A magnetic path in the direction of the arrow as shown by the dashed line in FIG. 5A is formed in the second gap 18, and a magnetic flux density 17 in the right direction is generated. Next, at the point of the phase 45 deg, all of the coils 15a to 15d of the first to fourth magnetic poles 11 to 14 have approximately +
A sine wave alternating current of 0.7 current is applied, and a magnetic path in the direction of an arrow is formed in the gap 18 of the quadrupole electromagnet 2 as indicated by the wavy line in FIG. 15B, and a magnetic flux density 17 in the upper right direction is generated. . Also, at the point of the phase 90 deg, the coils 1 of the first magnetic pole 11 and the third magnetic pole 13
Since a sine wave alternating current of +1 current is applied only between 5a and 15c, and is not applied between the coils 15b and 15d of the second magnetic pole 12 and the fourth magnetic pole 14, the gap 18 of the quadrupole electromagnet 2 is shown in FIG. A magnetic path in the direction of the arrow as shown by the dashed line in c) is formed, and an upward magnetic flux density 17 is generated.

As described above, 90 deg as shown in FIG.
When two kinds of sine wave alternating currents having different phases are applied to the coils 15a to 15d of the quadrupole electromagnet 2 as described above,
Each phase point (0 deg, 45 deg, 90 deg) shown in FIG.
g, 135 deg, 180 deg, 225 deg, 27
At 0 deg, 315 deg, and 360 deg), each magnetic path is formed in the direction of an arrow indicated by a broken line as shown in FIGS. 5A to 5I, and the magnetic flux density 17 in each magnetic flux density direction is generated. I do. Then, the sinusoidal alternating currents (0 deg, 90 deg) shown in FIG. 4 are continuously supplied to the quadrupole electromagnet 2, so that the gap 18 of the quadrupole electromagnet 2 is shown in FIGS. 5 (a) to 5 (i). The magnetic flux density 17 in each magnetic flux density direction is generated repeatedly and sequentially, and the gap 18 positioned on the trajectory of the charged particle beam 1 is formed.
Generates a rotating magnetic field for rotating and scanning the charged particle beam 1 within a predetermined range.

As described above, according to the radiotherapy apparatus shown in this embodiment, as shown in FIG. 4, between two pairs of coils (between 29a and 29c and between 29b and 29d) wound around opposed magnetic pole cores. Since two types of sinusoidal alternating currents with 90 deg phase shifts are applied to control the generation of magnetic flux density, the quadrupole scanning electromagnet 2 as shown in FIG. Scanning means for rotatingly scanning the charged particle beam 1 with an electromagnet is configured,
It is possible to obtain a radiation therapy apparatus which has a better rotational symmetry of the charged particle beam 1 than the conventional radiation therapy apparatus, has a small gantry configuration and is excellent in operability, and is extremely effective for radiation therapy. 5A to 5I, reference numerals 25a and 25b to 33a and 33b denote quadrupole electromagnets 2 at respective phase points in the coil current explanatory diagram shown in FIG.
The direction of the magnetic flux guided by the yoke 16 of FIG.

Further, in the radiotherapy apparatus according to the present embodiment shown in FIG. 1, the scatterer 3 is provided on the downstream side of the scanning means 2, which is charged before the beam radius is expanded by the scatterer 3. This is for rotating and scanning the particle beam 1, and the scatterer 3 may be provided on the upstream side of the scanning means 2. As described above, the charged particle beam 1 having good rotational symmetry can be obtained. However, when the scatterer 3 is
The scanning means 2 must rotationally scan the charged particle beam 1 having the expanded beam radius.
In a radiotherapy apparatus in which the size of the scanning means 2 in the radial direction is large and the size of the gantry section is required to be reduced, the scatterer 3 disposed downstream of the scanning means 2 has a wobble constituting the scanning means 2. This is desirable in that the magnetic flux density uniform region of the electromagnet can be made small.

Embodiments 2 Next, another embodiment of the present invention will be described with reference to FIGS. The above embodiment. 1, a case where a quadrupole electromagnet is functioned as a wobble electromagnet as the scanning unit 2 has been described. However, the scanning unit 2 may be a multipolar electromagnet having four or more magnetic pole cores. A case will be described in which an electromagnet, for example, a hexapole electromagnet functions as a wobble electromagnet. FIG. 6 shows the embodiment shown in FIG. FIG. 6 is a cross-sectional configuration view of a hexapole electromagnet 34 used as a scanning unit 2 of the radiation therapy apparatus 1.
, 35 to 40 are magnetic pole iron cores of a hexapole electromagnet 34 in which the same pole is formed between a pair of opposed magnetic poles (35 is the first
A magnetic pole, 36 is a second magnetic pole, 37 is a third magnetic pole, 38 is a fourth magnetic pole, 39 is a fifth magnetic pole, and 40 is a sixth magnetic pole. ), 41
a to 41f are wound around these magnetic pole cores 35 to 40, respectively, and between the coils of the opposing magnetic pole cores (between the first magnetic pole 35 and the fourth magnetic pole 38, between the second magnetic pole 36 and the fifth magnetic pole 39).
And between the third magnetic pole 37 and the sixth magnetic pole 40), the coil 42 is connected in series by the magnetomotive force generated by the magnetomotive force generated by the coils 41a to 41f wound around the respective magnetic pole cores 35 to 40. Yoke for guiding magnetic flux, 4
The gap 4 is formed by the magnetic flux guided by the yoke 42.
4 is the magnetic flux density generated. The magnetic flux density 43 corresponds to the coils 41a to 4 wound around the magnetic pole cores 35 to 40, respectively.
The direction of magnetic flux density is determined by a sine wave AC current described later applied to 1f, and the hexapole electromagnet 34 acts as a wobble electromagnet by controlling the phase of the sine wave AC current as described later.

Next, the operation and action of the hexapole electromagnet 35 will be described in detail with reference to FIGS. 7 and 8A to 8G. FIG. 7 is a coil current explanatory diagram showing the phase relationship of three types of sine wave alternating current supplied to the hexapole electromagnet 34 as the scanning means according to the present embodiment, and FIG.
8 (g) show phase points (0 deg, 60 deg, 120 deg, 180 deg) of the coil current explanatory diagram shown in FIG.
(g, 240 deg, 300 deg, 360 deg) are magnetic flux density explanatory diagrams showing magnetic flux density directions of respective magnetic flux densities generated in the gap 44 by the hexapole electromagnet 34. In FIG. 7, the horizontal axis represents the phase,
The vertical axis represents the current value (cu) of the sine wave AC current at each phase point.
8 (a) to 8 (g), only the first magnetic pole 35 is denoted by a reference numeral, and the other is omitted.
In the description of the present embodiment, a sine wave AC current (0 deg) having an initial phase of 0 deg shown in FIG. 7 is applied to the first magnetic pole 35 and the fourth magnetic pole 38, and an initial phase of 60 deg is applied to the second magnetic pole 36 and the fifth magnetic pole 39. Sine wave alternating current (60 deg)
The third magnetic pole 37 and the sixth magnetic pole 40 have an initial phase of 120 de.
g of sine wave AC current (120 deg) is applied, and the sine wave AC current (0 deg) applied to the coils 41a and 41d of the first magnetic pole 35 and the fourth magnetic pole 38, respectively.
g), the sinusoidal alternating current (60 deg) applied to the coils 15b and 15e of the second magnetic pole 36 and the fifth magnetic pole 39, and the coils 15c and 15 of the third magnetic pole 37 and the sixth magnetic pole 40.
The sinusoidal alternating current (120 deg) applied to f
As shown in FIG. 7, the phase is shifted by 60 degrees in the initial phase.

First, at the point of the phase 0 deg, the second magnetic pole 3
6 and the fifth magnetic pole 39, the third magnetic pole 37 and the sixth magnetic pole 40 between the coils 41b and 41e, and between the coils 41c and 41f approximately +
A 0.7 current sine wave alternating current is supplied, and the coils 41a and 41d of the first magnetic pole 35 and the fourth magnetic pole 38 are supplied.
Since no voltage is applied between the gaps, a magnetic path is formed in the gap 44 of the hexapole electromagnet 34 in the direction of the arrow as shown by the dashed line in FIG. 8A, and the magnetic flux density 43 in the right direction is generated. Next, at the point of the phase 60 deg, the coils 41a of the first magnetic pole 35 and the fourth magnetic pole 38, and the second magnetic pole 36 and the fifth magnetic pole 39
About + 0.7cur between 41d and 41d and between 41b and 41e
Since the sine wave alternating current of the Rent is supplied and is not applied between the coils 41c and 41f of the third magnetic pole 37 and the sixth magnetic pole 40, the gap 44 of the hexapole electromagnet 34 is indicated by the wavy line in FIG. A magnetic path is formed in the direction of the arrow as shown, and a magnetic flux density 43 in the lower right direction is generated. Phase 1
At the point of 20 deg, about +0.7 current between the coils 41a and 41d of the first magnetic pole 35 and the fourth magnetic pole 38.
Is supplied between the coils 41c and 41f of the third magnetic pole 37 and the sixth magnetic pole 40.
Since the sine-wave alternating current of the Rent is supplied and is not applied between the coils 41b and 41e of the second magnetic pole 36 and the fifth magnetic pole 39, the gap 44 of the hexapole electromagnet 34 is indicated by a wavy line in FIG. A magnetic path is formed in the direction of the arrow as shown, and a magnetic flux density 43 in the lower left direction is generated.

As described above, the six-pole electromagnet 34 of the radiotherapy apparatus according to the present embodiment has a six-pole electromagnet 34 as shown in FIG.
Three kinds of sine wave AC currents each having a phase shift of 0 deg are supplied, and the three kinds of sine wave AC currents whose phases are controlled as shown in FIG. 7 to FIG.
The phase points (0 deg, 60 d
eg, 120 deg, 180 deg, 240 deg, 3
00deg, 360deg), a sine-wave AC current of about ± 0.7 current is supplied between any two pairs of adjacent magnetic pole cores, and no sine-wave AC current is supplied between the remaining pair of magnetic pole cores. 8 (a) to 8 (g) appear in the gap 44 of the hexapole electromagnet 34.
Each magnetic path in the direction of the arrow indicated by the dashed line is formed, and a magnetic flux density 43 in each magnetic flux density direction is generated. The magnetic flux density 43 in each magnetic flux density direction as shown in FIGS.
Are sequentially and repeatedly generated in the gap 44 of the charged particle beam, a rotating magnetic field is generated in the gap 44 of the scanning means 34 located on the trajectory of the charged particle beam, and the charged particle beam 1 is rotationally scanned in a predetermined range by the rotating magnetic field. FIG.
8A to 8G, reference numerals 45 to 51 denote hexapole magnets 3 at respective phase points in the coil current explanatory diagram shown in FIG.
4 shows the directions of magnetic fluxes guided by the yoke 42, and the magnetic flux density 43 generated in the gap 44 by these magnetic flux directions.
Is determined.

As described above, according to the radiotherapy apparatus shown in the present embodiment, between the coils (between 41a and 41d, between 41b and 41d) wound around three pairs of magnetic pole cores disposed opposite to each other.
e, between 41c and 41f), as shown in FIG.
Since three types of sinusoidal alternating currents whose phases are shifted by eg each are applied to control the generation of magnetic flux density, the six-pole scanning electromagnet 35 as shown in FIG. 6 can also function as a wobble electromagnet. The same effects as those of the radiotherapy apparatus described in the above embodiment can be obtained.
In the present embodiment, the hexapole electromagnet is described as functioning as a wobble electromagnet.However, as described above, a rotating magnetic field is generated in a gap between the multipole electromagnets as described above for a multipole electromagnet having six or more magnetic pole cores. By supplying a sinusoidal alternating current whose phase is controlled as described above, it is possible to function as a wobble electromagnet. Further, according to the radiotherapy apparatus shown in the present embodiment, since the scanning means 34 is constituted by a hexapole electromagnet, the coils 41a to 41f always have a constant current value (two pairs) as shown in FIG. Approximately 0.7 current between pole cores and 0 curre for the remaining pair
nt AC current is supplied), and the magnetic flux density of uniformity and good uniformity is generated in the gap 44 more uniformly than the scanning means including the quadrupole electromagnet 2 described above, and the rotational symmetry is further improved. A rotating magnetic field can be generated.

Japanese Patent Application Laid-Open No. 1-217898 discloses that a quadrupole electromagnet also functions as a hexapole electromagnet in the column of the problem to be solved by the invention. The use of a multi-pole electromagnet is disclosed, but this is merely an example of the operation of a multi-pole electromagnet. The present invention uses the multipolar electromagnet as the scanning means of the radiotherapy apparatus as described above, and connects the coils of the magnetic pole cores facing each other of the multipole electromagnet in series to form a paired coil. By applying a plurality of phase-controlled sinusoidal alternating currents as shown in Fig. 4 or Fig. 8 between them, a multipolar electromagnet with four or more poles functions as a wobble electromagnet of the radiation therapy device.

Embodiments 3. Next, another embodiment of the present invention will be described with reference to FIGS. In Embodiment 1.2 described above, the radiation therapy apparatus in which the gantry section configuration is compact and a charged particle beam having good rotational symmetry is obtained by causing the multipolar electromagnet to function as a wobble electromagnet of the radiation therapy apparatus has been described. However, even with such a radiotherapy apparatus using a scanning means composed of a multipolar electromagnet, penumbra generated in a charged particle beam irradiated to an affected part or the like cannot be suppressed. Therefore, in the present embodiment, a radiation therapy apparatus capable of irradiating a charged particle beam in which penumbra is suppressed by a scanning unit including a multipolar electromagnet will be described.

FIG. 9 is a schematic configuration diagram schematically showing a radiation therapy apparatus according to another embodiment of the present invention. In FIG. 9, reference numeral 52 denotes a first scanning means composed of a multipolar electromagnet, and 53 Is constituted by a multi-pole scanning electromagnet similarly to the first scanning means 52, and the second scanning electromagnet is provided in the opposite direction to the first scanning means 52.
Is a second scanning means for generating a rotating magnetic field. For example, when each of these scanning means 52 and 53 is constituted by the above-described quadrupole electromagnet, a sine wave alternating current whose phase is controlled as shown in FIG. Each of the scanning means supplied with a sine wave alternating current phase-controlled so as to generate a rotating magnetic field in each direction functions and acts as a wobble electromagnet. In this case, quadrupole or hexapole electromagnets may be combined, or multipole electromagnets having different numbers of magnetic poles may be combined, and the same effect is obtained. In the drawings, the same reference numerals as those in the above embodiment are used.
The same or corresponding portions are shown, and the description of these specific configurations is omitted.

Next, the operation of the radiotherapy apparatus according to this embodiment will be described in detail with reference to FIG. FIG. 10 shows a charged particle beam 1 in the radiotherapy apparatus according to the present embodiment.
FIG. 10 is a beam trajectory explanatory diagram showing the beam trajectory of FIG.
In the figures, 54 and 55 are gaps between the first scanning means 52 and the second scanning means 53 arranged on the beam trajectory of the charged particle beam 1, and 56 is the first scanning means 52 and the second scanning means 53.
Is a beam trajectory of the charged particle beam 1 which is rotationally scanned by the respective rotating magnetic fields of the scanning means 53 and whose beam diameter is expanded in a cone shape by the scatterer 3.

A charged particle beam from a radiation source (not shown) is accelerated by an accelerator or the like as in the above embodiment, and is incident on the first scanning means 52. The first scanning means 52 functions as a wobble electromagnet by being supplied with a plurality of sinusoidal alternating currents whose phases are controlled.
The charged particle beam 1 incident on the first scanning means 2
Is rotationally scanned in the radial direction by the first rotating magnetic field generated by. The charged particle beam 1 that has passed through the first scanning means 52 is rotationally scanned in the radial direction under the action of the first rotating magnetic field of the first scanning means 52,
The second scanning means 53 is expanded conically as shown in FIG.
Is incident on. Next, the second scanning means 53 moves the charged particle beam 1 in a direction opposite to the first rotating magnetic field of the first scanning means 52.
The phase-controlled sinusoidal alternating current is supplied so as to generate a second rotating magnetic field for rotationally scanning the charged particle beam 1 incident on the second scanning means 53 from the second scanning means 53. Rotational scanning is performed in the beam axis direction by the generated second rotating magnetic field. The charged particle beam 1 that has passed through the second scanning means 53 is rotationally scanned in the axial direction by the action of the second rotating magnetic field of the second scanning means 53, and therefore, as shown in FIG. The light is focused and incident on the scatterer 3.

Therefore, when the charged particle beam 1 rotationally scanned by the first scanning means 52 passes through the second scanning means 53 and passes through the scatterer 3, the charged particle beam 1 is moved in its axial direction. One of the scatterers 3 focused as shown in FIG.
Form a beam trajectory that passes through a point. And the scatterer 3
The charged particle beam 1 incident on one point is
After being scattered in a cone with the focus at 7, the dose monitor 5
Of the diseased part, which passes through the ridge filter 6, the range filter 7, the block collimator 8, and the movable collimator 9, is shaped into a beam shape according to the shape of the irradiation surface, and is irradiated to the affected part or the like positioned at the isocenter 10. Irradiated on the surface.

As described above, according to the radiotherapy apparatus of the present embodiment, the charged particle beam 1 rotationally scanned by the first scanning means 52 has a rotating magnetic field in a direction opposite to that of the first scanning means 52 as described above. Is rotated by the second scanning means 53 in the direction opposite to that of the first scanning means 52, so that the point of incidence of the charged particle beam 1 on the scatterer 3 is not circular but point-like. And for the irradiation surface,
It is possible to irradiate the charged particle beam 1 scattered so as not to cause a shift in the irradiation position and close to an ideal dose distribution as shown in FIG.

As described above, according to the radiation therapy apparatus according to the present embodiment, the incident point of the charged particle beam 1 on the scatterer 3 is point-shaped as shown in the beam trajectory of the charged particle beam 1 in FIG. 17, the charged particle beam 1, which is suppressed in the influence of the penumbra close to the ideal dose distribution as shown in FIG.
In addition to the effects of Embodiment 1.2 described above, the beam shape of the charged particle beam 1 can be set to the maximum size according to the shape of the affected part, and a radiation treatment apparatus with greatly improved treatment efficiency can be obtained. Can be. Further, since the dose distribution of the charged particle beam 1 irradiated to the affected part or the like can be close to the ideal dose distribution as shown in FIG. 17, the edge portion of the dose distribution can be formed almost perpendicular to the irradiation surface. While the beam shape of the shaped charged particle beam can be set to the maximum size close to the shape of the affected area, normal cell tissues other than the affected area are also improved in safety by suppressing the irradiation of charged particle beams. A therapeutic device can be obtained. Incidentally, as an additional effect, the charged particle beam 1
Is not circular, but is incident on the scatterer 3 in the form of a spot, so that the width of the scatterer 3 itself in the radial direction can be configured to be small, and the dose monitor 5, the range filter 7, the collimators 8, 9 and the like are also arranged in the width direction. Can be used, which contributes to downsizing of the gantry section configuration.

Embodiment 4 The above embodiment. In the radiotherapy apparatus of No. 3,
Although the description has been given of the case where the multipolar electromagnet is used as the scanning means of the radiation therapy apparatus, the same applies to the radiotherapy apparatus using the conventional scanning means in which the X-direction scanning electromagnet and the Y-direction scanning electromagnet constitute a wobble electromagnet. It is possible to irradiate a charged particle beam in which the amount is suppressed. This will be described below with reference to FIGS. FIG. 11 is a schematic configuration diagram schematically showing a radiation therapy apparatus according to another embodiment of the present invention. In FIG. 11, reference numeral 58 denotes a first scanning unit, which includes an X-direction scanning electromagnet 58a and a Y-direction scanning A wobble electromagnet 59 composed of an electromagnet 58b is provided with a pair of scanning electromagnets (X-direction scanning electromagnet 5 like the first scanning means 58).
9a and the second scanning electromagnet 59b).
Is a wobble electromagnet which is a scanning means. In the drawings, the same reference numerals as those in the above-described embodiment denote the same or corresponding parts, and a description of these specific structures will be omitted.

Next, the operation of the radiotherapy apparatus according to this embodiment, in particular, the operation of the scanning means 58 and 59 will be described with reference to FIGS. FIG. 12 shows the first type shown in FIG.
FIG. 13 is a coil current explanatory diagram showing each phase relationship of each sine wave alternating current supplied to the scanning means 58 and the second scanning means 59, respectively. FIG. 13 shows the charged particle beam 1 in the radiotherapy apparatus of the present embodiment. FIG. 13 is a beam trajectory explanatory diagram showing a beam trajectory. In FIG. 13, reference numeral 60 denotes a scatterer which is rotationally scanned by a first rotating magnetic field and a second rotating magnetic field of a first scanning means 58 and a second scanning means 59. 3 is a beam trajectory of the charged particle beam 1 whose beam diameter is expanded in a cone shape. First, a charged particle beam from a radiation source (not shown) is accelerated by an accelerator or the like, and the first scanning means 5
8 is incident. Here, the X-direction scanning electromagnet 58a and the Y-direction scanning electromagnet 58b of the first scanning means 58 have the configuration shown in FIG.
2, a sine wave alternating current (0
deg) and a sine wave AC current (90 deg) having an initial phase of 90 deg indicated by a broken line, respectively.
A first rotating magnetic field for rotatingly scanning the charged particle beam 1 in the radial direction is generated in the scanning means 58, and the charged particle beam 1 incident from the upstream side is rotationally scanned in a conical shape as shown in FIG.

Next, the charged particle beam 1 rotationally scanned by the first scanning means 58 is kept in a conical shape while the second scanning means 59 is being used.
And is rotationally scanned in the beam axis direction by the second rotating magnetic field. Here, the second scanning means 59 supplies the X-direction scanning electromagnet 59a and the Y-direction scanning electromagnet 59b with a sine wave alternating current (180 deg) having an initial phase of 180 deg shown by a dashed line in FIG. 12 and an initial phase 270d shown by a two-dot chain line.
eg, a sinusoidal alternating current (270 deg) is supplied, and a second rotating magnetic field in a direction opposite to the first rotating magnetic field generated from the first scanning means 58 is generated.
The charged particle beam 1 incident from the upstream side is rotationally scanned in an inverted conical shape as shown in FIG.

As described above, when the charged particle beam 1 rotationally scanned by the first scanning means 58 passes through the second scanning means 59 and passes through the scatterer 3, the charged particle beam 1
Is a scatterer 3 converged in the axial direction as shown in FIG.
To form a beam trajectory passing through one point. Then, the charged particle beam 1 incident on one point of the scatterer 3 is scattered in a cone shape with the incident point 57 as a focal point, and then the dose is detected by the dose monitor 5, and the ridge filter 6, the range filter 7, Block collimator 8, movable collimator 9
, And is shaped into a beam shape according to the shape of the irradiation surface, and is irradiated onto the irradiation surface such as an affected part positioned at the position of the isocenter 10.

As described above, also in the radiotherapy apparatus of the present embodiment, the charged particle beam 1 rotationally scanned by the first scanning means 58 generates a rotating magnetic field in the direction opposite to that of the first scanning means 58. Since the second scanning magnetic field of the second scanning means 59 is rotationally scanned in the opposite direction, the point of incidence of the charged particle beam 1 on the scatterer 3 can be made not a circle but a point, and Can irradiate the charged particle beam 1 scattered so as not to cause a shift in the irradiation position and close to the ideal dose distribution as shown in FIG. However, according to the radiotherapy apparatus of the present embodiment, there is a problem that the size of the gantry in the beam traveling direction is increased.

Embodiment 5 Next, another embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. In the above embodiment, the radiation therapy apparatus having good rotational symmetry and the radiation therapy apparatus capable of irradiating the charged particle beam with the penumbra suppressed have been described. However, the charged particle beam 1 is a scatterer as described above. 3, the beam radius of the charged particle beam 1 is widened, so that the point of incidence of the charged particle beam 1 on the scatterer 3 does not become point-like (for example, the circularly charged particle beam is rotated and scanned to form the scatterer 3). In such a case, an extra charged particle beam incident from the scatterer 3 to the outside of the irradiation field is generated, and the fixed frame of the ridge filter 6 and the range filter 7 disposed downstream of the scatterer 3 and The problem of scattering by these driving mechanisms arises. Therefore, in the radiation therapy apparatus according to the present embodiment, an extra charged particle beam scattered by such a scatterer 3 and incident outside the irradiation is shielded, and a ridge filter 6 disposed downstream of the scatterer 3 is disposed. The radiotherapy apparatus which can prevent the scattering of the fixed frame of the range filter 7 and the driving mechanism thereof will be described.

FIG. 14 is a schematic configuration diagram of the radiotherapy apparatus according to the present embodiment. In the radiation therapy apparatus according to the present embodiment, for example, the above-described embodiment. A second collimator 61 for shielding particles is further disposed downstream of the scatterer 3 of the radiation therapy irradiation apparatus shown in FIG. In FIG. 14, reference numeral 61 denotes a metal having a thickness greater than or equal to the range of the charged particle beam 1 and has a conical shape with the scatterer 3 at the apex and an opening outside the wobbler radius Rw on the isocenter plane. Is a second collimator formed in a shape capable of shielding the charged particle beam 1 scattered by the scatter filter 3 of the extra charged particle beam 1 scattered out of the irradiation field by the scatterer 3 by the second collimator 61. , The scattering of the fixed frame of the range filter 6 and the driving mechanism thereof is prevented. In the drawings, the same reference numerals as those in the above-described embodiment denote the same or corresponding parts, and a description of these specific structures will be omitted.

Next, the manner of shielding the charged particle beam 1 of the radiotherapy apparatus according to the present embodiment will be explained with reference to FIG. In the present embodiment, a case where a uniform dose distribution is formed for an irradiation field having an irradiation radius of 2F will be described. As shown in FIG. 15, the charged particle beam 1 incident on the gap 18 of the scanning means 2, which is a wobble electromagnet, is rotationally scanned conically by the rotating magnetic field of the scanning means 2 and is incident on the scatterer 3. Here, 62 is a scattering point 63 of the scatterer 3
Is a charged particle beam scattered in a cone shape with the focal point as a focal point. In the plane at the position P1, a normal distribution 64 centering on the point O1 is formed. On the isocenter plane at the position (P2) of the isocenter 10, the point O2 is set. Scattering radius radius R at the center
A normal distribution 65 of 1 / e = 1.43F is formed. As described above, since the charged particle beam 1 is incident on the scatterer 3 while being rotationally scanned, the charged particle beam 1 has a circular focus at a position shifted from the beam orbit axis 10 in the scatterer 3. And a charged particle beam whose irradiation position is shifted is irradiated.

Here, 2F on the isocenter plane
When it is desired to form an irradiation field in the range of (radius F), the charged particle beam outside the 2 RW does not contribute to the dose distribution. Therefore, in a state where the second collimator 61 is not provided, extra charged particles that do not contribute to the dose distribution are provided. The beam is incident on the outside of the irradiation field and causes scattering in the fixed frame of the ridge filter 5 and the range filter 6 arranged on the downstream side of the scatterer 3 and the driving mechanism thereof, but the radiation therapy apparatus according to the present embodiment In FIG. 15, as shown in FIG. 15, a second collimator 61 is provided on the downstream side of the scatterer 3 and its opening is set to 2 RW, so that an extra charged particle beam (charged particles incident outside the 2 RW). Beam) is the second collimator 61
And only the charged particle beam contributing to the dose distribution is incident on the irradiation field.

As described above, according to the radiotherapy apparatus according to the present embodiment, an extra charged particle beam scattered by the scatterer 3 and incident outside the irradiation field is shielded by the second collimator 61. Thus, it is possible to obtain a radiation treatment apparatus that can prevent scattering by the fixed frame of the ridge filter 6 and the range filter 7 provided on the downstream side of the scatterer 3 and the driving mechanism thereof. Note that the radiotherapy apparatus shown in FIG. 14 uses a scanning unit composed of a multipolar electromagnet, but uses two scanning electromagnets (an X-direction scanning electromagnet and a Y-direction scanning electromagnet) like a conventional scanning unit. The present invention can be applied to a radiation therapy apparatus, and can be applied to the above embodiment. The present invention can also be applied to radiotherapy apparatuses as described in 2 to 4, and the above-described effects can be obtained by being provided on the downstream side of the scanning means of these radiotherapy apparatuses.

[0049]

As described above, according to the first aspect of the present invention, the scatterer provided on the trajectory of the charged particle beam and the dose of the charged particle beam scattered by the scatterer are detected. A dose monitor, a collimator that changes the beam shape of the charged particle beam scattered by the scatterer according to the shape of the irradiation object, and provided on the trajectory of the charged particle beam, and on the trajectory of the charged particle beam A first scanning means for generating a first rotating magnetic field, and a second rotating magnetic field provided on the trajectory of the charged particle beam and having a direction opposite to the first rotating magnetic field to generate a second rotating magnetic field. Since the second scanning means for rotating and scanning the charged particle beam by a magnetic field is provided, the penumbra of the charged particle beam is suppressed, and the charged particle beam whose dose distribution end shape is substantially perpendicular to the irradiation surface is formed. Can be irradiated and the charged particle beam Beam shape can be set to the maximum, and the irradiation of the charged particle beam to the normal tissue can be obtained an excellent radiotherapy apparatus of the irradiation efficiency can be prevented.

According to the second aspect of the present invention, since the first and second scanning means are arranged upstream of the scatterer, a scanning means having a short magnetic flux length can be used. The size of the gantry section can be reduced.

According to the third aspect of the present invention, since the scanning means is constituted by the multipolar electromagnet in which the same pole is formed between the opposed magnetic pole cores, the gantry section is small in size and rotationally symmetric. A charged particle beam having good properties can be irradiated.

According to the fourth aspect of the present invention, the range shifter provided on the trajectory of the charged particle beam and the beam shape of the charged particle beam whose irradiation energy is adjusted by the range shifter are changed to the shape of the irradiation object. And a quadrupole electromagnet having the same pole formed on a pair of opposed magnetic pole iron cores. Two types of alternating currents having different 90 deg phases are applied to the charged particle beam at the upstream of the range shifter. Scanning means for generating a rotating magnetic field on the trajectory is provided, so that the charged particle beam is circularly scanned by the rotating magnetic field generated in the same plane, and the charged particle beam with good rotational symmetry can be irradiated. .

According to the fifth aspect of the present invention, the range shifter provided on the trajectory of the charged particle beam, and the beam shape of the charged particle beam whose irradiation energy is adjusted by the range shifter can be adjusted by changing the beam shape of the irradiation target. It is composed of a collimator that changes according to the shape and a six-pole electromagnet in which the same pole is formed between opposed magnetic pole cores. Three types of alternating currents whose phases are shifted by 60 deg are applied, and Scanning means for generating a rotating magnetic field on the trajectory of the charged particle beam is provided, so that the charged particle beam is circularly scanned by the rotating magnetic field generated in the same plane with little rotation unevenness, and the charged particles have good rotational symmetry. The line can be irradiated.

According to the sixth aspect of the present invention, a scatterer provided on the trajectory of the charged particle beam, a dose monitor for detecting the dose of the charged particle beam scattered by the scatterer, A range shifter that changes the irradiation energy of the charged particle beam based on the dose detected by the dose monitor, and a collimator that changes the beam shape of the charged particle beam whose irradiation energy is adjusted by the range shifter according to the shape of the irradiation target. A first scanning means comprising a multipolar electromagnet having the same pole formed between opposed magnetic pole cores, and generating a rotating magnetic field on the trajectory of the charged particle beam;
A multi-pole electromagnet in which the same pole is formed between opposed magnetic pole iron cores generates a second rotating magnetic field in a direction opposite to the first rotating magnetic field, and the charged particle beam is generated by the second rotating magnetic field. And the second scanning means for rotationally scanning is provided, so that a charged particle beam having good rotational symmetry can be irradiated, penumbra is suppressed, and the dose distribution end is substantially perpendicular to the irradiation surface. Thus, it is possible to irradiate the affected part with a charged particle beam, and it is possible to obtain a radiation therapy apparatus with good treatment efficiency.

According to the seventh aspect of the present invention, the second collimator is provided between the scatterer and the dose monitor to block unnecessary charged particle beams emitted outside the irradiation field. It is possible to obtain a radiotherapy apparatus in which unnecessary charged particle beams scattered by the scatterer are prevented from being scattered by a range shifter or the like provided on the downstream side.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention. 1 is a schematic configuration diagram illustrating a radiation therapy apparatus according to No. 1.

FIG. 2 is a sectional configuration diagram showing a scanning unit of the radiation therapy apparatus shown in FIG.

FIG. 3 is a treatment explanatory diagram showing a general treatment situation by a radiation therapy apparatus.

FIG. 4 shows an embodiment of the present invention. FIG. 3 is a coil waveform diagram showing a sinusoidal alternating current supplied to the scanning unit according to No.

FIG. 5 shows an embodiment of the present invention. FIG. 4 is a magnetic flux density explanatory diagram showing a magnetic flux density direction of each magnetic flux density generated by the scanning means of FIG.

FIG. 6 is a sectional view showing a scanning means of a radiation therapy apparatus according to another embodiment of the present invention.

FIG. 7 is a coil waveform diagram showing a sinusoidal alternating current supplied to a scanning unit according to another embodiment of the present invention.

FIG. 8 is a magnetic flux density explanatory diagram showing a magnetic flux density direction of each magnetic flux density generated by a scanning unit according to another embodiment of the present invention.

FIG. 9 is a schematic configuration diagram showing a radiotherapy apparatus according to another embodiment of the present invention.

10 is a beam trajectory explanatory diagram showing a beam trajectory of a charged particle beam in the radiotherapy apparatus shown in FIG. 9;

FIG. 11 is a schematic configuration diagram showing a radiation therapy apparatus according to another embodiment of the present invention.

12 is a coil waveform diagram showing a sinusoidal alternating current supplied to a scanning unit of the radiation therapy apparatus shown in FIG.

FIG. 13 is a beam trajectory explanatory diagram showing a beam trajectory of a charged particle beam in the radiotherapy apparatus shown in FIG. 11;

FIG. 14 is a schematic configuration diagram showing a radiotherapy apparatus according to another embodiment of the present invention.

FIG. 15 is an explanatory diagram showing a state in which a charged particle beam is shielded by a second collimator of the radiotherapy apparatus shown in FIG. 14;

FIG. 16 is a schematic configuration diagram showing a conventional radiation therapy apparatus.

FIG. 17 is a dose distribution diagram showing an ideal dose distribution state of a charged particle beam.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 charged particle beam 2 scanning means 3 scatterer 4 dose monitor 5 ridge filter 6 range shifter 7 block collimator 8 movable collimator 9 isocenter 10 beam orbit axis 11, 35 first magnetic pole iron 12, 36 second magnetic pole iron 13, 37th 3 pole iron cores 14, 38 fourth pole iron cores 39 fifth pole iron cores 40 sixth pole iron cores 52, 58 first scanning means 53, 59 second scanning means 61 second collimator

Claims (7)

[Claims] 1. A scatterer provided on a trajectory of a charged particle beam, a dose monitor for detecting a dose of the charged particle beam scattered by the scatterer, and a beam of the charged particle beam scattered by the scatterer A collimator for changing the shape in accordance with the shape of the irradiation target, a first scanning means provided on the trajectory of the charged particle beam, and generating a first rotating magnetic field on the trajectory of the charged particle beam; A second scanning unit that is provided on the trajectory of the charged particle beam, generates a second rotating magnetic field in a direction opposite to the first rotating magnetic field, and rotates and scans the charged particle beam with the second rotating magnetic field; A radiation therapy apparatus comprising: 2. A radiotherapy apparatus according to claim 1, wherein said first and second scanning means are arranged upstream of said scatterer. 3. The radiotherapy apparatus according to claim 1, wherein said scanning means is constituted by a multipolar electromagnet in which the same pole is formed between opposed magnetic pole cores. 4. A range shifter provided on a trajectory of a charged particle beam, a collimator for changing a beam shape of the charged particle beam whose irradiation energy is adjusted by the range shifter in accordance with a shape of an object to be irradiated, and a facing magnetic pole It is composed of a quadrupole electromagnet with the same pole formed between the iron cores, and 90d
scanning means for applying two types of alternating currents having different eg phases to generate a rotating magnetic field on the trajectory of the charged particle beam in the upstream portion of the range shifter. 5. A range shifter provided on a trajectory of a charged particle beam, and a collimator for changing a beam shape of the charged particle beam whose irradiation energy is adjusted by the range shifter in accordance with a shape of an irradiation object. A six-pole electromagnet having the same pole formed between the magnetic pole cores,
Scanning means for applying three types of alternating currents having phases shifted by 0 deg to generate a rotating magnetic field on the trajectory of the charged particle beam upstream of the range shifter. 6. A scatterer provided on a trajectory of a charged particle beam, a dose monitor for detecting a dose of the charged particle beam scattered by the scatterer, and the charging device based on the dose detected by the dose monitor. A range shifter that changes the irradiation energy of the particle beam, a collimator that changes the beam shape of the charged particle beam whose irradiation energy is adjusted by this range shifter according to the shape of the irradiated object, and the same pole between the facing magnetic pole cores A first scanning means for generating a rotating magnetic field on the trajectory of the charged particle beam, and a multipolar electromagnet in which the same pole is formed between opposed magnetic pole cores, A second scanning means for generating a second rotating magnetic field in a direction opposite to the first rotating magnetic field and rotatingly scanning the charged particle beam with the second rotating magnetic field. A radiation therapy apparatus characterized by the above-mentioned. 7. The apparatus according to claim 1, further comprising a second collimator provided between the scatterer and the dose monitor and configured to block a charged particle beam incident outside the irradiation field. 7. The radiotherapy apparatus according to claim 6.