JPH10263098A - Charged particle irradiating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of so-called a shadowy blur and surely irradiate a beam regardless of the movement of a material to be irradiated by providing first and second deflecting electromagnets which are respectively turned round the axis of a beam, and varying the exciting amount of each deflecting electromagnet to irradiate a beam to a designated area of a part to be irradiated. SOLUTION: A beam 1 from an accelerator is deflected at an angle A by a first deflecting electromagnet 11a, and further deflected reversely at an angle B by a second deflecting electromagnet 11b, whereby as a result, the beam on the incidence side and the deflected beam 4 are made parallel to apply the deflected beam 4 to the surface 5 to be irradiated. By the rotation of the deflecting electromagnet 11, the deflecting surface of the beam 1 is rotated to determine the radiating surface of the beam 1 in the circumferential direction of the surface 5 to be irradiated round the axis 21, and the radial irradiating position of the surface 5 to be irradiated is determined by an electric current flowing through the deflecting electromagnets 11a, 11b, so that the deflected beam 4 can be irradiated to a desired area of the surface 5 to be irradiated. Thus, the occurent of the half shadow can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charged particle irradiation apparatus for irradiating a beam to be irradiated by deflecting a beam accelerated by an accelerator and extracted by a first bending electromagnet and a second bending electromagnet. .

[0002]

2. Description of the Related Art FIG. 4 shows, for example, "Construction Report of Heavy Ion Beam Cancer Treatment System NIRS-M109HIMAC-009".
It is explanatory drawing of the conventional charged particle irradiation apparatus shown by 98 pages-102 pages. In the figure, reference numeral 1 denotes a beam accelerated and taken out from the accelerator, 2 denotes an X-axis deflection electromagnet which deflects the beam 1 to the X-axis, 3 denotes a Y-axis deflection electromagnet which deflects the beam 1 to the Y-axis, and 4 denotes their deflection. Deflected beams 5 and 5 deflected by the electromagnets 2 and 3 are irradiation surfaces of the object to be irradiated with the deflected beam 4. Here, the X axis and the Y axis are the beam 1
Are two axes orthogonal to each other in a plane perpendicular to the traveling direction of

In this charged particle irradiation apparatus, a beam 1 of charged particles (for example, electrons, protons, and heavy ions) extracted from an accelerator is directed to an irradiation surface 5. For example, when a lesion such as cancer is killed by the charged particle beam 1, a treatment table or the like is adjusted so that the exit of the beam 1 faces the lesion of the patient. In order to irradiate a wide irradiation surface 5 with a fine beam 1 uniformly, an X-axis deflecting electromagnet 2 deflecting in the X direction
And a pair of Y-axis bending electromagnets 3 for deflecting in the Y-axis direction. X-axis bending electromagnet 2 and Y
A sinusoidal wave is used as the exciting current of the shaft bending electromagnet 3,
The current values are changed to change the magnetic flux densities of the bending electromagnets 2 and 3, respectively, to produce a deflection beam 4 deflected in the X-axis direction and the Y-axis direction. I have. Note that a scatterer may be arranged between the deflecting electromagnets 2 and 3 and the irradiation surface 5 as a means for expanding the deflecting beam 4.

[0004] FIG. 5 shows, for example, "A joint research report of the 1995 National Institute of Radiological Sciences Heavy Ion Beam Therapy, NIRS-M-116 HIMAC-
FIG. 13 is an explanatory diagram of a conventional respiratory-gated irradiation apparatus shown in “Pages 179 to 180”. In the figure, 6 is an irradiation system device including an X-axis electromagnet 2, a Y-axis electromagnet 3, a scatterer (not shown), 7 is a human body, 8 is a position detection sensor attached to the human body 7, 9 is a position detection sensor 8 This is a control device for controlling the beam extraction device 10 of the accelerator on-off by the output from the accelerator.

[0005] In this charged particle irradiation apparatus, the affected part of the human body 7 is irradiated with the deflected beam 4 that has passed through the irradiation system equipment 6. When the affected part moves due to the respiration of the human body 7, the beam 4 hits a normal tissue. You need to stop the beam to avoid it. Therefore, the movement of the affected part is detected by the position detection sensor 8, and when the affected part moves, a trigger signal or the like is generated from the control device 9 to control the operation of the beam extraction device 10 of the accelerator, and the beam is not extracted from the accelerator. Like that.

[0006]

In the conventional charged particle irradiation apparatus shown in FIG. 4, by controlling the magnetic flux density of the bending electromagnets 2 and 3 by the current of the X-axis bending electromagnet 2 and the Y-axis bending electromagnet 3, The scanning within the irradiation surface 5 is performed, and the degree of freedom of scanning of the deflection beam 4 is determined by changing the current value of each of the X-axis deflection electromagnet 2 and the Y-axis deflection electromagnet 3.
Therefore, when an irradiation point in the irradiation surface 5 is determined, the angle of incidence at that point is inevitably determined. For example, there is only one point that is perpendicular to the irradiation surface 5 consisting of a plane, and all other points are The deflection beam 4 hits the irradiation surface 5 at a certain angle. By the way, a collimator that covers the part other than the affected part is used in order to prevent the deflection beam 4 from being irradiated to an object other than the irradiated part such as the affected part. There is a problem that a so-called penumbra blur occurs in which the contrast of the boundary with the protection area that should not be irradiated is so-called, and the protection area is irradiated with the deflecting beam 4.

In the conventional charged particle irradiation apparatus shown in FIG. 5, when the affected part moves due to, for example, respiration of the human body 7, the control unit 9 operates to stop taking out the beam 1 from the accelerator. There is a problem that the time required for the treatment becomes longer.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, so that a so-called penumbra does not occur, and even if an object to be irradiated is moved, It is an object of the present invention to obtain a charged particle irradiation apparatus in which an object is reliably irradiated with a beam.

[0009]

According to a first aspect of the present invention, there is provided a charged particle irradiation apparatus comprising a first bending electromagnet and a second bending electromagnet, each rotatable about a beam axis. A first bending electromagnet and the second bending electromagnet;
The beam is irradiated to a predetermined portion of the irradiated portion by changing the excitation amount of the bending electromagnet.

In the charged particle irradiation apparatus according to a second aspect of the present invention, the beam deflection surface of the first deflection electromagnet and the beam deflection surface of the second deflection electromagnet are on the same plane, and The direction of the swing angle of the beam of the deflection electromagnet is opposite to the direction of the swing angle of the beam of the second deflection electromagnet, and the values of the respective swing angles are the same, and after passing through the second deflection electromagnet, Is a beam which is parallel to the beam before being incident on the first bending electromagnet.

In the charged particle irradiation apparatus according to a third aspect of the present invention, a position detection sensor for detecting a position of an irradiation point of the irradiated portion, and a first bending electromagnet and a second deflection electromagnet based on a signal from the position detection sensor. And an excitation amount control device for irradiating a beam to an irradiation point by controlling the excitation amount of the bending electromagnet.

Further, in the charged particle irradiation apparatus according to a fourth aspect of the present invention, the first bending electromagnet and the second bending electromagnet are rotatable around the beam axis.

In the charged particle irradiation apparatus according to a fifth aspect of the present invention, the beam deflecting surface of the first deflecting electromagnet and the beam deflecting surface of the second deflecting electromagnet are on the same plane, and The first deflection electromagnet and the second deflection electromagnet such that the deflection angle of the deflection electromagnet and the deflection angle of the second deflection electromagnet are opposite to each other, and the beam irradiates a certain irradiation point of the irradiated portion. Is changed.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a layout diagram showing a charged particle device according to a first embodiment of the present invention. In the drawing, reference numeral 1 denotes a beam of charged particles from an accelerator, and 11 denotes a rotation rotating about an axis 21 of the beam 1 from the accelerator. The deflection electromagnet body 11 includes a mechanism (not shown). The deflection electromagnet body 11 generates a magnetic field in a direction perpendicular to the plane of the paper so as to deflect the beam in the plane of the paper, and has a first magnetic flux density of the same value in different directions. And the second bending electromagnet 11b. Reference numeral 4 denotes a deflection beam deflected by the deflection electromagnet main body 11, reference numeral 5 denotes an irradiation surface of an object to be irradiated with the deflection beam 4, and reference numeral 12 is provided between the deflection electromagnet main body 11 and the irradiation surface 5, and should be irradiated. Deflected beam 4 in a place that is not
This is a collimator that prevents irradiation of light.

In the above charged particle irradiation apparatus, the beam 1 is deflected by an angle A by a first bending electromagnet 11a and deflected by an angle B by a second bending electromagnet 11b in the opposite direction. Beam 1 and bending electromagnet 11
The beam becomes parallel to the deflected beam 4 after passing through b, and the deflected beam 4 is irradiated on the irradiation surface 5. Also, the rotation of the deflection electromagnet 11 rotates the deflection surface of the beam 1, so that
The irradiation position of the beam 1 in the circumferential direction of the irradiation surface 5 about the axis 21 is determined, and the irradiation position of the irradiation surface 5 in the radial direction is determined by the current flowing through the bending electromagnets 11a and 11b. Beam 1 from the accelerator at a given location
It is possible to irradiate a beam 4 parallel to

Therefore, for example, the irradiation surface 5 and the bending electromagnet 1
When the collimator 12 is inserted between the collimator 1 and a shadow portion where the deflection beam 4 does not hit, the deflection beam irradiates the surface of the collimator 12 perpendicularly. And irradiation with clear contrast is possible.

Embodiment 2 FIG. FIG. 2 is an explanatory view showing a charged particle irradiation apparatus according to Embodiment 2 of the present invention. In the figure, the second bending electromagnet 13b is the first bending electromagnet 1
Deflected in the same plane as 3a, but generated a magnetic field in the opposite direction,
The magnitude of the magnetic flux density is determined such that the resulting deflected beam 4 passes through the irradiation point 22 on the axis 21 of the beam 1. Further, the bending electromagnets 13a, 1
By rotating the beam 3b about the axis 21 of the beam 1 and changing the excitation amount of the bending electromagnets 13a and 13b, the irradiation point 22 can be irradiated at an arbitrary solid angle from a certain solid angle.

As described above, in the charged particle irradiation apparatus according to the second embodiment, the deflection beam 4 deflected by the deflection electromagnet main body 13 including the first deflection electromagnet 13a and the first deflection electromagnet 13b is within a certain solid angle. The irradiation point 22 can be irradiated at any angle. Therefore, the irradiation dose can be superimposed on the portion to be irradiated, and
If there is an important organ 14 on the upstream side of the main body and there is a place where irradiation is not desired at all, the bending electromagnets 13a and 13b are excited so as to avoid the important organ 14, and the important organ 14
It is possible to irradiate the affected part effectively while protecting the affected part.

Embodiment 3 FIG. 3 is an explanatory view showing a charged particle irradiation apparatus according to Embodiment 3 of the present invention. In the figure, reference numeral 15 denotes a position detection sensor attached to the surface of the human body 7 or the like, which detects the amount of movement of the irradiation point 22. Reference numeral 16 denotes an excitation amount control device that changes the excitation amount of the first deflection electromagnet 11a and the second deflection electromagnet 11b based on the output from the position detection sensor 15. The deflection beam is always deflected even if the irradiation point 22 moves. 4 is the irradiation point 22
The excitation amounts of the first bending electromagnet 11a and the second bending electromagnet 11b are determined so as to approach. The deflecting surfaces of the deflecting electromagnets 11a and 11b are adjusted to be a plane including the moving direction of the irradiation point 22. Although the bending electromagnets 11a and 11b have a rotating mechanism, they need not be.

In the charged particle irradiation apparatus according to the third embodiment, even if the irradiation point 22 moves due to breathing or the like, the deflection beam 4 is always applied to the irradiation point 22.
The beam 1 from the accelerator is effectively used without waste. Further, it is effective to combine the charged particle irradiation apparatus of the third embodiment with not only a synchrotron that is extracted as a pulse but also a cyclotron that can continuously extract a beam.

[0021]

As described above, according to the charged particle irradiation apparatus of the first aspect of the present invention, the first bending electromagnet and the second bending electromagnet are rotated about the beam axis, and the first bending electromagnet is rotated. By changing the amount of excitation of the deflection electromagnet and the second deflection electromagnet, it is possible to easily and reliably irradiate a predetermined portion of the irradiated portion with the beam.

According to the charged particle irradiation apparatus of the present invention, the deflection beam after passing through the second deflection electromagnet is parallel to the beam before being incident on the first deflection electromagnet. For example, when a collimator is inserted between the irradiation unit and the bending electromagnet to form a shadow portion where the deflection beam does not hit, since the deflection beam irradiates the surface of the collimator vertically, so-called penumbra blur occurs. That is, irradiation with clear contrast is possible.

According to the charged particle irradiation apparatus of the third aspect of the present invention, the position detecting sensor for detecting the position of the irradiation point of the irradiation target, the first bending electromagnet based on the signal from the position detecting sensor, and Since an excitation amount control device for controlling the excitation amount of the second deflection electromagnet and irradiating the irradiation point with a beam is provided, even if the irradiation point moves by breathing or the like, the deflection beam is always applied to the irradiation point. The beam from the accelerator is effectively used without waste.

According to the charged particle irradiation apparatus of the fourth aspect of the present invention, the first bending electromagnet and the second bending electromagnet can be rotated about the beam axis, respectively. It is possible to easily irradiate the beam at a predetermined position in the circumferential direction about the axis.

According to the charged particle irradiation apparatus of the present invention, the beam deflecting surface of the first deflection electromagnet and the beam deflecting surface of the second deflection electromagnet are on the same plane, and The first deflection electromagnet and the second deflection electromagnet are arranged such that the swing angle of the first deflection electromagnet and the swing angle of the second deflection electromagnet are opposite to each other, and the beam irradiates a certain irradiation point of the irradiated portion. Since the amount of excitation of the bending electromagnet is changed, the irradiation dose can be superimposed on the part to be irradiated.For example, if there is an important organ upstream of the irradiation point and there is a part that you do not want to irradiate, By exciting the bending electromagnet, it becomes possible to irradiate the affected part effectively while protecting important organs.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a charged particle irradiation apparatus according to Embodiment 1 of the present invention.

FIG. 2 is an explanatory view of a charged particle irradiation apparatus according to Embodiment 2 of the present invention.

FIG. 3 is an explanatory view of a charged particle irradiation apparatus according to Embodiment 3 of the present invention.

FIG. 4 is an explanatory view of a conventional charged particle irradiation apparatus.

FIG. 5 is an explanatory view of another example of a conventional charged particle irradiation apparatus.

[Explanation of symbols]

1 beam, 4 deflection beams, 5 irradiation surfaces, 11a, 1
3a 1st bending electromagnet, 11b, 13b 2nd bending electromagnet, 15 position detection sensor, 16 excitation amount control device, 21 axis, 22 irradiation point.

Claims (5)

[Claims] 1. A charged particle irradiation apparatus for irradiating a beam to be irradiated by deflecting a beam accelerated by an accelerator and taken out by a first deflecting electromagnet and a second deflecting electromagnet. A rotatable first deflection electromagnet and a second deflection electromagnet provided at predetermined locations on the irradiated portion by changing the excitation amounts of the first deflection electromagnet and the second deflection electromagnet; A charged particle irradiation device that irradiates a beam to the surface. 2. A charged particle irradiation apparatus for irradiating a part to be irradiated by deflecting a beam accelerated by an accelerator and extracted by a first deflecting electromagnet and a second deflecting electromagnet, wherein the beam of the first deflecting electromagnet is used. And the deflection surface of the beam of the second bending electromagnet are on the same plane,
The direction of the swing angle of the beam of the first bending electromagnet and the direction of the swing angle of the beam of the second bending electromagnet are opposite,
In addition, the charged particle irradiation device has the same swing angle value, and the deflection beam after passing through the second deflection electromagnet is parallel to the beam before being incident on the first deflection electromagnet. 3. A charged particle irradiation apparatus that irradiates a beam to be irradiated with a beam accelerated and extracted by an accelerator,
A position detection sensor for detecting the position of the irradiation point of the irradiated portion; and a signal from the position detection sensor for controlling the amount of excitation of a first bending electromagnet and a second bending electromagnet to irradiate the irradiation point with a beam. A charged particle irradiation apparatus comprising: 4. The charged particle irradiation apparatus according to claim 2, wherein the first bending electromagnet and the second bending electromagnet are each rotatable about a beam axis. 5. The deflection surface of the beam of the first deflection electromagnet and the deflection surface of the beam of the second deflection electromagnet are on the same plane, and the swing angle of the first deflection electromagnet and the second deflection electromagnet. And the excitation angles of the first and second deflection electromagnets are changed so that the beam irradiates a predetermined irradiation point of the irradiated portion with the swing angles of the first and second deflection electromagnets being opposite to each other. The charged particle irradiation device according to any one of claims 1, 3, and 4.