JPH07272900A - Microtron device for medical treatment - Google Patents

Abstract

PURPOSE:To take out an electron beam with high efficiency by carrying an electron beam brought under deflection control according to an irradiation angle of electron beam or X-rays for a patient up to an irradiation head and so decreasing floor space for device installation and the number of lenses. CONSTITUTION:An electron beam(EB) of electrons from an electron source 3, accelerated due to a uniform magnetic field made by an electromagnet 2 and a high-frequency acceleration electric field in a microtron electron accelerator 101 is carried by an EB carrying system 4a. EB reaching to an EB deflection means 5 is controlled for deflection by this means 5 according to irradiation angle of EB or X-rays 105 for a patient 102. The EB is then carried to an irradiation head 6 by an EB carrying system 4b. An EB carrying system 4b and the means 5, is disposed, the means 5 and the head 6 both being rotatable. Accordingly, EB carrying distance is short and device installation floor space is small, and further, Eb is taken out efficiently with a small number of lens means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a therapeutic microtron device, and more particularly to a therapeutic microtron device suitable for electron beam transportation.

[0002]

2. Description of the Related Art A therapeutic microtron device is a device mainly used for cancer treatment, in which an electron beam accelerated by a microtron electron accelerator is irradiated as it is or after being converted into an X-ray to irradiate a patient. is there. As shown in FIG. 6, the structure of a conventional therapeutic microtron device is as follows: a microtron electron accelerator 101 for accelerating electrons, an electron beam carrier system 4 for carrying an electron beam accelerated by the accelerator, an electron beam or an X-ray 105. It is composed of a treatment gantry 104 for irradiating the patient 102 with the treatment and a treatment table 103.

In the microtron electron accelerator 101, an accelerating cavity 1 for generating a high frequency accelerating electric field by inputting a microwave is arranged in a uniform magnetic field of an electromagnet 2, and the electric field and magnetic field cause electrons to move in a circular orbit to accelerate. It is a device that does. Further, the electron beam transport system 4 includes a vacuum pipe 13 partially having a magnetic shield effect, quadrupole electromagnets 11a to 11d which are lens means for focusing the electron beam, and deflection electromagnets 51a to 51c for deflecting the electron beam. It consists of By this electron beam transfer system 4, the electron beam accelerated and taken out by the microtron electron accelerator 101 is transferred to the irradiation head 6 of the therapeutic gantry 104. The therapeutic gantry 104 is installed on the rotary support 8 and is configured to be rotatable, and includes an electron beam or an X-ray 105.
Is configured to be able to irradiate the patient 102 from various angles.

Documents describing this type of conventional technique include pages 200-205, Medical Imaging and Radiation Equipment Handbook (1989), edited by Japan Radiation Equipment Industry Association.

[0005]

However, in the above-mentioned conventional technique, the therapeutic gantry 104 (weight: about 4 t) is mechanically rotated according to the irradiation angle of irradiating the patient with the electron beam or the X-ray. In order to support the rotation, a rotary support 8 having a thickness of about 500 mm was installed. Therefore, there is a problem that the installation floor area of the device is large. Further, since the electron beam is carried inside the rotary support 8 along the thickness direction, the electron beam carrying system 4 is long, and in order to prevent a loss caused by the divergence of the electron beam during that time, a quadrupole as a lens means is used. There is also a problem that it is necessary to install many electromagnets 11a to 11d.

The present invention has been made in order to solve the above problems, and has a small installation floor area of the entire apparatus and a therapeutic micro-machine capable of efficiently extracting an electron beam with a small number of lens means. An object is to provide a thoron device.

[0007]

In order to achieve this object, in the present invention, instead of the therapeutic gantry and its rotary support used in the prior art therapeutic microtron device, a fixed structure is used. And an electron beam deflecting means for controlling the deflection angle of the electron beam according to the irradiation angle of the electron beam or X-ray emitted from the irradiation head onto the patient. An irradiation head is provided which is provided with an electron beam transfer means for transferring the electron beam deflection-controlled by the deflection means to the irradiation head, and which is in contact with the support and rotatable about the patient's body axis. To provide.

Here, the electron beam deflecting means is composed of an electromagnet and is mechanically rotated according to the irradiation angle of the electron beam or X-ray to the patient. Then, the electron beam deflecting means has a structure in which the entrance / exit surface is inclined with respect to the entrance / exit direction of the electron beam as necessary so as to have a lens effect. On the other hand, the electron beam deflecting means may be composed of a plurality of fixed electromagnets and electromagnetically controlled.

Furthermore, a lens means is provided in the path of the electron beam to adjust the focusing action according to the irradiation angle of the electron beam or X-ray to the patient. A circular microtron electron accelerator is used as the microtron electron accelerator that is a means for generating a high-energy electron beam.

[0010]

In this therapeutic microtron device, an electron beam carrying support for carrying an electron beam, the deflection of which is controlled according to an arbitrary irradiation angle, to the irradiation head is fixedly installed. The rotating support of the therapeutic gantry is unnecessary, and the therapeutic microtron device having a small installation floor area can be obtained. Further, since the rotation support is unnecessary, the length of the electron beam transport system is shorter than that of the conventional technique, so that the number of lens means is smaller than that of the conventional technique.
It is possible to carry out electron beam transportation with the same extraction efficiency as in the past. That is, it is possible to realize a therapeutic microtron device which has a small installation floor area and can extract an electron beam with high efficiency by a small number of lens means.

[0011]

【Example】

(Embodiment 1) FIG. 1 is a device sectional view showing an embodiment of a therapeutic microtron device according to the present invention.

In this embodiment, a circular microtron electron accelerator 101 for accelerating electrons, a first electron beam transport system 4a for transporting an electron beam taken out from the accelerator, and an electron beam or X-ray 105 to a patient 102. Electron beam deflection means 5 for controlling the deflection angle of the electron beam according to the irradiation angle, irradiation head 6 for irradiating the patient 102 with the electron beam or X-ray 105, and irradiation with the electron beam deflection-controlled according to the arbitrary irradiation angle. It is composed of a second electron beam transport system 4b for transporting to the head 6, and an electron beam transport support 7 including the electron beam deflecting means 5 and the second electron beam transport system 4b. Here, the electron beam carrying support 7 is fixedly installed. Further, the electron beam deflecting means 5 and the irradiation head 6 are rotatably installed.

Next, a circular microtron electron accelerator 1
The internal structure of 01 will be described. First, inside the Microtron electron accelerator 101, a microwave of 3 GHz is input.
An accelerating cavity 1 that creates a high-frequency accelerating electric field is provided in an electromagnet 2 that creates a uniform magnetic field (about 0.2 T). On the outside of the wall surface of the acceleration cavity 1, an electron source 3 composed of a cathode and an anode formed coaxially is provided. Although not shown, the acceleration cavity 1 is provided with three electron beam passage holes through which the accelerated electron beam passes. In the uniform magnetic field, a movable magnetic shield pipe 12 for changing the orbit of the electron beam, and an electron beam deviated from the circular orbit by the magnetic shield pipe 12 to the outside of the uniform magnetic field, A fixed vacuum pipe 13 partially having a magnetic shield effect is provided.

Next, the internal structure from the first electron beam transport system 4a to the irradiation head 6 will be described. A quadrupole electromagnet 11 is installed in the first electron beam carrier system 4a as a lens means for focusing the electron beam. Beyond that, a rotatable electron beam deflector 5 for deflecting the electron beam to a desired angle, a second electron beam carrier system 4b,
An electron beam carrier 7 having a double-cone shape and having cavities inside is installed therein. The shape of the electron beam carrier 7 is shown in FIG. In this embodiment,
An electromagnet is used as the electron beam deflecting means 5 and is configured to be rotatable about the incident direction of the electron beam to the electron beam deflecting means 5 as a central axis. An irradiation head 6 is movably provided at an end of the second electron beam transport system 4b so that the irradiation head 6 can be rotated about the body axis of the patient 102. The irradiation head 6 includes an electromagnet 52 that deflects an electron beam.
And an X-ray target, a collimator, and the like, and the collimator portion is rotatably installed with the emission direction of the electron beam or the X-ray 105 as the central axis.

Next, the operation of this embodiment will be described. The electrons emitted from the electron source 3 draw a circular orbit by the uniform magnetic field generated by the electromagnet 2, and then enter the acceleration cavity 1 through the electron beam passage hole. In the acceleration cavity 1, the electrons are deflected by the uniform magnetic field and at the same time initially accelerated by the high-frequency acceleration electric field. Then, it is emitted from another electron beam passage hole to a uniform magnetic field region. The emitted electrons draw a circular orbit and enter the acceleration cavity 1 again. Here, the electrons are further accelerated by the high-frequency acceleration electric field, emitted from the third electron beam passage hole to the uniform magnetic field region, and draw a larger circular orbit to accelerate the cavity 1.
Re-inject inside. After that, the electrons reach a desired energy by repeating the acceleration by the acceleration cavity 1 and the circular orbital motion in the uniform magnetic field. Here, the energy obtained by the electron in one acceleration is about 1 MeV, and the energy of the electron after n times acceleration is (about 1 MeV) × (n + 1). Although not shown, the Microtron electron accelerator according to this configuration can accelerate up to 30 times. The electrons having reached the desired energy are removed from the circular orbit by a movable magnetic shield pipe 12 installed on the circular orbit, and further pass through a fixed vacuum pipe 13 partially having a magnetic shield effect. Are taken out of the uniform magnetic field. The extracted electron beam is focused by the quadrupole electromagnet 11 and then deflected by the rotatable electron beam deflection means 5 at an angle according to the irradiation direction of the electron beam or the X-ray 105 to the patient 102, and the electron beam is transported. It is guided to the second electron beam carrier system 4b inside the supporting body 7. Then, the electron beam is deflected in a direction perpendicular to the body axis of the patient 102 by the deflection electromagnet 52 of the irradiation head 6 at the end of the electron beam transport system 4b, and exits from the electron beam transport support 7 to reach the target. The electron beam is passed through the collimator or the collimator as it is, or the X-ray 105 is irradiated onto the patient 102.

According to this embodiment, the rotary support 8 in the prior art is not required, and the installation floor area of the device can be reduced. Further, since the distance for transporting the electron beam is shortened by the thickness of the rotary support 8 and the electron beam is deflected at an obtuse angle, the beam transport is performed in comparison with the conventional technique in which the electron beam is deflected a plurality of times at substantially right angles. The distance has been further shortened. As a result, the electron beam transport distance is 60 in total.
The length can be shortened by 0 mm or more, and at the same time, the number of lens means for focusing the electron beam can be reduced from the conventional four to one. That is, it was possible to obtain a therapeutic microtron device in which the installation floor area of the device is small and the electron beam can be extracted with high efficiency by a small number of lens means.

(Embodiment 2) Next, FIG. 3 shows a device configuration of a second embodiment of the therapeutic microtron device according to the present invention.

In the second embodiment, the installation direction of the microtron electron accelerator 101 in the first embodiment and the electron beam extraction mechanism are changed. As shown in FIG. 3, electrons are taken out of the uniform magnetic field by a magnetic shield pipe 12 installed so as to be movable almost right next to the acceleration cavity 1.
A bending electromagnet 53 that moves integrally with the magnetic shield pipe 12 guides it in one direction. Further, an electron beam is transported by a first electron beam transport system 4a including a vacuum pipe 13 and a quadrupole electromagnet 11 which is a lens means.
For this type of microtron electron accelerator 101, deflection controllable electron beam deflecting means 5, electron beam transport system 4b, and electron beam transport support 7 according to the present invention are provided.
Etc. were provided in the same manner as in Example 1. As a result, reduction of the installation floor area of the device and reduction of the lens means by shortening the electron beam transport distance have been realized. Further, since the microtron electron accelerator 101 has a configuration in which the magnetic shield pipe 12 for extracting the electron beam is installed almost right next to the acceleration cavity 1, the magnetic shield pipe 12 is different from that in the first embodiment.
The diameter of can be increased. As a result, the electron beam extraction efficiency was further improved as compared with the first embodiment.

(Third Embodiment) A third embodiment according to the present invention will be described with reference to FIG.

In the third embodiment, the direction of the treatment table 103 is changed so that the body axis direction of the patient 102 changes by 90 degrees as compared with the first and second embodiments. However, the microtron electron accelerator 101 and the first electron beam transport system 4 for guiding the electrons emitted therefrom to the electron beam transport support 7
"a" has the same structure as in the first embodiment. And
In the third embodiment, the support 7 for electron beam transportation is shown in FIG.
As shown in FIG. 3, the columnar shape is formed with a circular ring as the bottom surface.
Although not shown, electromagnets are installed on both sides of the electron beam carrying support 7 to create a uniform magnetic field inside the electron beam carrying support 7 perpendicular to the plane of the drawing. Inside the electron beam carrying support 7, a fixed electron beam deflecting means 5 that can be electromagnetically controlled according to the irradiation angle of the electron beam or the X-ray 105 to the patient 102, and a deflection electromagnet 52.
And a movable irradiation head 6 including With this configuration, the electron beam emitted from the microtron electron accelerator 101 passes through the first electron beam transport system 4a and is electromagnetically deflected and controlled by the electron beam deflecting means 5 to move inside the electron beam transport support 7. Draw a circular orbit to proceed. The electron beam is deflected by the deflecting electromagnet 52 rotating inside the support body 7 according to a desired irradiation angle to the patient 102, taken out of the electron beam carrying support body 7, and then delivered to the patient 102. 105 is irradiated.
The quadrupole electromagnet 11 that is a lens means provided in the first electron beam transport system 4a for suppressing the divergence of the electron beam is controlled according to the irradiation angle to the patient 102 so that it has a lens effect. It is configured. In the therapeutic microtron device according to the third embodiment, the patient 102
The body axis direction and the axis direction of the electron beam transport system 4a are orthogonal to each other. As a result, a therapeutic microtron device having a shorter device size in the axial direction of the electron beam transport system 4a than in the first and second embodiments was obtained.

The embodiments of the present invention have been described above.
The present invention is not limited to the above embodiment, and for example, the microtron electron accelerator 101 used for accelerating the electron beam may be a race track type. The numerical values shown in the above embodiments are merely examples, and the present invention is not limited to these. For example, the acceleration energy for one time of the microtron electron accelerator 101, the maximum number of times of acceleration, etc. may be any numerical values, and the uniform magnetic field strength and the microwave frequency may satisfy the synchronization condition of the microtron. , Any number is acceptable. Further, the acceleration method of the microtron electron accelerator 101 is not limited to the above embodiment, and for example, the acceleration method microtron electron accelerator having two electron beam passage holes in the acceleration cavity 1 and not performing initial acceleration. Can also be used. The second electron beam transport system 4b may be configured to perform deflection at substantially right angles a plurality of times. In that case, the electron beam transport support 7 may have a hollow cylindrical shape or a truncated cone shape. Good. In addition, in the first and second embodiments, the patient 10
Electron beam deflection means 5 for controlling the deflection angle of the electron beam depending on the irradiation angle of the electron beam or X-ray 105 onto the beam 2.
May be a permanent magnet, or may be one that performs electromagnetic control with a fixed electromagnet. However, in the case of electromagnetic control, deflection control is performed by a combination of a plurality of deflectors that individually perform horizontal deflection and vertical deflection. Further, the electron beam deflecting means 5 and the deflectors 52 and 53 used in the present invention are so arranged that the entrance / exit surface has a desired angle with respect to the entrance / exit direction of the electron beam so as to have a lens effect itself. You may comprise. In short, an electron beam deflecting means capable of controlling the deflection of the electron beam according to the irradiation angle to the patient 102, and a fixed electron beam capable of carrying the deflection controlled electron beam according to the irradiation angle to the irradiation head. Any therapeutic microtron device having a carrier for transportation may be used. Further, in the above embodiment, the electron beam deflecting means and the lens means are constituted by electromagnets and quadrupole electromagnets, respectively, but they may have other configurations, and the numbers thereof are not limited to those in the above embodiment. is not.

[0022]

As described above, in the therapeutic microtron device according to the present invention, the fixed electron beam carrier is installed and the irradiation angle of the electron beam or the X-ray to the patient is provided therein. By providing a means for transporting the electron beam, the deflection of which is controlled according to the above, to the irradiation head, the transport distance of the electron beam can be shortened, and therefore, the installation floor area of the device can be reduced and the number of lenses is small. The electron beam can be extracted with high efficiency by the means.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a therapeutic microtron device according to the present invention.

FIG. 2 is a configuration diagram of an electron beam carrying support in FIG.

FIG. 3 is a second therapeutic microtron device according to the present invention.
FIG. 3 is a configuration cross-sectional view showing the example of FIG.

FIG. 4 is a third therapeutic microtron device according to the present invention.
FIG. 3 is a configuration cross-sectional view showing the example of FIG.

FIG. 5 is a configuration diagram of an electron beam carrying support in FIG.

FIG. 6 is a sectional view showing the configuration of a conventional therapeutic microtron device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Accelerating cavity 2 ... Electromagnet 3 ... Electron source 4, 4a, 4b ... Electron beam conveyance system 5 ... Electron beam deflection means 51a-51d, 52, 53 ... Deflection electromagnet 6 ... Irradiation head 7 ... Electron beam conveyance support 8 ... Rotating support 11, 11a to 11d ... Quadrupole electromagnet 12 ... Magnetic shield pipe 13 ... Vacuum pipe 101 ... Microtron electron accelerator 102 ... Patient 103 ... Treatment table 104 ... Treatment gantry 105 ... Electron beam or X-ray

Claims (8)

[Claims] 1. A treatment by deflecting and transporting an electron beam accelerated by a microtron electron accelerator and guiding it to an irradiation head, and the electron beam is irradiated from the irradiation head as it is or converted into an X-ray and irradiated to a patient. In a therapeutic microtron device to be performed, an electron beam deflection means for controlling a deflection angle of the electron beam according to an irradiation angle of the electron beam or X-ray to a patient, and the deflection-controlled electron beam to the irradiation head. A therapeutic microtron device having a fixed support for electron beam transport, which includes an electron beam transport means for transporting to. 2. The irradiation head is provided so as to be in contact with the electron beam carrying support, and is configured to be rotatable about the body axis of the patient.
The therapeutic microtron device according to 1. 3. The electron beam deflecting means has a center axis in the incident direction of the electron beam to the electron beam deflecting means.
The therapeutic microtron device according to claim 1 or 2, wherein the therapeutic microtron device is installed so as to be mechanically rotatable according to an irradiation angle to the patient. 4. The therapeutic microtron device according to claim 1, 2 or 3, wherein said electron beam deflecting means comprises an electromagnet. 5. The electron beam deflecting means is composed of one or a plurality of fixed electromagnets, and the deflection angle of the electron beam is electromagnetically controlled according to the irradiation angle to the patient. 3. The therapeutic microtron device according to claim 1 or 2. 6. The entrance / exit surface of the electron beam deflector is inclined with respect to the entrance / exit direction of the electron beam so that the electron beam deflector has a lens effect. The therapeutic microtron device according to any of the above items. 7. A lens means is provided in the path of the electron beam, and the focusing action on the electron beam is adjusted according to the irradiation angle of the electron beam or X-ray to the patient. The therapeutic microtron device according to any one of items 1 to 6. 8. The therapeutic microtron device according to claim 1, wherein the microtron electron accelerator is a circular microtron electron accelerator.