JPH07283000A - Microtron device for use in therapy - Google Patents

Abstract

PURPOSE:To provide a microtron device for use in therapy of such a configuration that a plurality of treatment gantries are installed for one microtron electron accelerator, with which the output electron beam from the accelerator can effectively be transported to the gantries. CONSTITUTION:A microtron device for therapeutical use is equipped with a rotary supporting body 2 to rotate a microtron electron accelerator 1 mechanically and a plurality of treatment gantries 6a, 6b. The accelerator 1 is rotated so that the electron beam emitting direction is changed, and a beam takeout pipe 8 is coupled with a vacuum pipe 6a for transporting the electron beam, and the gantry to conduct beam transportation is switched.

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 used for treating a patient, and more particularly to a therapeutic microtron device capable of supplying an electron beam to a plurality of therapeutic gantry by one microtron electron accelerator. It relates to the device.

[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 used as it is, or it is converted into an X-ray to irradiate a patient. is there. FIG. 6 shows the configuration of a conventional therapeutic microtron device. This apparatus includes a microtron electron accelerator 1 for accelerating electrons, an electron beam carrier system for carrying an electron beam accelerated by the accelerator 1, and an irradiation head 3 for irradiating a patient with an electron beam or an X-ray. It is composed of a gantry 4 and a treatment table 7 on which a patient is placed.

In the microton electron accelerator 1, an accelerating cavity 10 for generating a high-frequency accelerating electric field by inputting a microwave is arranged in a uniform magnetic field, and the magnetic field and the electric field cause electrons to move in circular orbits and sequentially increase in height. It is a device that accelerates to energy. The accelerated electron beam is removed from the circular orbit by the magnetic shield pipe 13 and taken out of the magnetic field. Further, the electron beam transport system includes a quadrupole electromagnet 5 that focuses the electron beam and a deflection electromagnet 15 that deflects the electron beam.
And a vacuum pipe 6 through which the electron beam passes, by which the output electron beam from the accelerator 1 is conveyed to the irradiation head 3 of the therapeutic gantry 4. Further, the treatment gantry 4 is configured to be rotatable so that the patient can be irradiated with electron beams and X-rays from various angles.

On the other hand, a therapeutic microtron apparatus is also provided in which a plurality of therapeutic gantry is provided for one Microtron electron accelerator and the output electron beam from the accelerator is supplied to each therapeutic gantry. Exists. The device configuration is shown in FIG. In this apparatus, deflection electromagnets 15a, 15b, 15s are additionally provided in the electron beam transport system, and the output electron beam from the accelerator 1 is supplied to each treatment gantry by changing the magnetic field direction of the deflection electromagnet 15s. It is adapted to be switched to 4a and 4b.

Documents describing this type of conventional technique include: Medical Radiation Equipment Handbook, edited by Japan Radiation Equipment Industry Association, (1989), No. 200.
To page 205.

[0006]

However, in the above-mentioned conventional technique, when a plurality of therapeutic gantry is provided for one microtron electron accelerator, each electron beam is fed to the electron beam carrier system. Bending electromagnets for switching to the treatment gantry are additionally required. Therefore, there is a problem that the electron beam transport system becomes longer by that amount and the electron beam transport efficiency is reduced.

The present invention has been made to solve such a problem, and in a therapeutic microtron apparatus in which a plurality of therapeutic gantry is provided for one microtron electron accelerator, the above-mentioned accelerator is used. It is an object of the present invention to provide a therapeutic microtron device capable of efficiently transporting an output electron beam to each therapeutic gantry.

[0008]

In order to achieve this object, in the present invention, means for mechanically rotating a microtron electron accelerator, a plurality of therapeutic gantry,
An electron beam transfer means arranged corresponding to a plurality of therapeutic gantry is provided, and the irradiation gantry is switched by rotating the microtron electron accelerator to change the emission direction of the electron beam. The configuration.

A circular microtron is used as the microtron electron accelerator, and when the microtron is mechanically rotated, the electron orbit plane in the accelerator is always rotated so as to be in the same horizontal plane.

[0010]

In this treatment microtron device, the electron beam can be switched to a plurality of treatment gantry without using a bending electromagnet, so that the length of the electron beam carrier system is shortened as compared with the prior art. It is possible,
As a result, the electron beam transport efficiency becomes higher than that of the conventional technique. That is, it is possible to realize a therapeutic microtron device capable of efficiently transporting an output electron beam from the microtron electron accelerator to a plurality of therapeutic gantry.

[0011]

【Example】

(Embodiment 1) FIG. 1 shows a top view of a therapeutic microtron device according to the present invention, and FIG. 2 shows a side view thereof.

First, in the therapeutic microtron apparatus according to the first embodiment, a cylindrical microtron electron accelerator 1 (diameter: 2200 mm, thickness: 500 mm, weight: about 10 t) and a microtron electron accelerator 1 are used. Rotating support 2 having a mechanism for rotationally supporting, therapeutic gantry 4a, 4b having irradiation heads 3a, 3b for irradiating a patient with an electron beam or X-ray, quadrupole electromagnets 5a, 5b and vacuum pipe 6a. , 6b, and the treatment tables 7a, 7b on which the patient is placed. Further, the microtron electron accelerator 1 is provided with a beam extraction pipe 8. Further, a vacuum valve 9 is provided at the end of the beam extraction pipe 8 and the vacuum pipes 6a and 6b.
9a and 9b are provided, respectively.

Next, the internal structure of the microtron electron accelerator 1 in this embodiment is shown in FIG. Microwave (3G
Hz) to create a high frequency accelerating electric field
0 is provided in an electromagnet 11 that creates a uniform magnetic field. An electron gun 12 is attached to the acceleration cavity 10. The electromagnet 11 includes a magnetic pole 111, a yoke 112,
It is composed of an exciting coil 113, and a uniform magnetic field of 0.21T is created by this. A movable magnetic shield pipe 13 is provided in the uniform magnetic field. Also, the part where the electrons move in a circular orbit is the vacuum container 1
It is kept in vacuum by 4.

Next, the operation of the microtron electron accelerator 1 will be described with reference to FIG. The electrons emitted from the electron gun 12 are guided into the acceleration cavity 10 and accelerated, and re-enter the acceleration cavity 10 in a uniform magnetic field by the electromagnet 11 in a circular orbit. Here, the electrons are further accelerated and re-inject into the acceleration cavity 10 in a larger circular orbit. This operation is repeated, and the electrons are accelerated until the desired energy is reached. The electron accelerated to a desired energy is removed from the circular orbit by the magnetic shield pipe 13 arranged on the circular orbit, and is taken out of the accelerator 1 by the beam extraction pipe 8.

Next, a method of switching the treatment gantry to which the electron beam is transferred will be described with reference to FIGS. 1 and 4. In the first embodiment, the microtron electron accelerator 1 is rotated by the rotating support 2 and the emission direction of the electron beam from the beam extraction pipe 8 is changed, so that the treatment gantry to which the electron beam is transported is switched. ing. FIG. 1 shows a case where an electron beam is transported to the treatment gantry 4a. In this case, the beam extraction pipe 8 and the vacuum pipe 6a are connected via an O-ring, the vacuum valves 9 and 9a are opened, and the vacuum valve 9b is closed. In addition, in FIG. 4, the microtron electron accelerator 1 is rotated by 180 degrees and the therapeutic gantry 4 is rotated.
This is the case where the electron beam is carried to b. However, in this case, before the rotation of the microtron electron accelerator 1, the connection between the beam extraction pipe 8 and the vacuum pipe 6a in FIG. 1 is released in advance, and although not shown, bellows or the like existing in the vacuum pipe 6a is used. Thus, the vacuum valve 9a is retracted so that the rotation of the electron accelerator 1 is not blocked. And the electron accelerator 1 is 180
After the rotation, the beam extraction pipe 8 and the vacuum pipe 6b are connected via an O-ring, and the vacuum valves 9 and 9 are connected.
b is opened and the vacuum valve 9a is closed. In this way
The treatment gantry to which the electron beam is transferred is switched. During the rotation of the Microtron electron accelerator 1, all the vacuum valves 9, 9a, 9b are closed, and the inside of the vacuum container 14 and the vacuum pipes 6a, 6b are closed.
The inside of b is always kept in a vacuum.

Although not shown in the drawings, an electron beam transfer system composed of a quadrupole electromagnet and a bending electromagnet is provided inside the therapeutic gantry 4a, 4b as in the prior art. The electron beam carried to the treatment gantry 4a, 4b is carried to the irradiation head 3a, 3b. Then, the electron beam is irradiated as it is or after being converted into X-rays to the patient.

By the way, in the microtron electron accelerator 1 of the first embodiment, the acceleration energy Eg per electron in the acceleration cavity 10 is about 1 MeV, and the total energy En of the electrons in the nth circular orbit is Eg. (N + 1). Although the maximum number of trajectories is only 14 turns in FIG. 3, it is possible to accelerate up to 35 turns in practice. Therefore, by moving and arranging the magnetic shield pipe 13 on each circular orbit (4 to 35 turns),
In a wide range of 5 to 36 MeV, an electron beam with energy every 1 MeV can be obtained.

The feature of the first embodiment is that the electron beam transport efficiency is superior to that of the prior art. In the first embodiment, since the bending electromagnet used for switching the electron beam used in the conventional technique is not required, the length of the electron beam carrier system can be made sufficiently shorter than that in the conventional technique. The beam transfer efficiency is higher than that of the conventional technique. For example, when the electron beam transport efficiency is compared with an actual device, it is about 90% in the conventional technique.
In Example 1, it could be about 98%.

(Second Embodiment) Next, a second embodiment according to the present invention will be described with reference to FIG. In the second embodiment, the number of therapeutic gantry is 4 in comparison with the two in the first embodiment.
It was added to the stand. By rotating the microtron electron accelerator 1 by 90 degrees by the rotating support 2, the output electron beam from the microtron electron accelerator 1 is supplied to each of the four treatment gantry 4a, 4b, 4b.
It can be conveyed to c and 4d.

Although various embodiments according to the present invention have been described above, the present invention is not limited to the above embodiments, and various modified configurations as shown below can be adopted. For example, in the above embodiment, the specifications of the Microtron electron accelerator 1 are as follows: maximum number of orbits: 35 turns, maximum energy: 36 MeV, diameter: 2200 mm, thickness: 500
mm, which is the number of orbits, energy,
It may be sized. In the above embodiment, the microwave frequency is 3 GHz and the uniform magnetic field strength is 0.21T.
However, this may be any frequency and magnetic field strength as long as the synchronization condition of the microtron is satisfied. Further, in the above-described embodiment, the method of opening and closing the vacuum valves 9 and 9a to 9d is used as a means for preventing vacuum leakage when switching the treatment gantry to which the electron beam is transferred. However, the structure is not limited to the above, and any structure may be used as long as it can prevent vacuum leakage. Further, in the above embodiment, the number of therapeutic gantry is two or four, but it may be any number as long as it is two or more. Further, in the above-described embodiment, the circular microtron is used as the microtron electron accelerator 1, but the microtron is not limited to this, and for example, a racetrack type microtron may be used.

[0021]

As described above, in the therapeutic microtron apparatus according to the present invention, a single microtron electron accelerator is mechanically rotated to change the emission direction of the electron beam, and thus a plurality of microtron electron accelerators are operated. Since the electron beam can be switched to the treatment gantry and can be transported in a short distance, the output electron beam from the accelerator can be efficiently transported to each treatment gantry.

[Brief description of drawings]

FIG. 1 is a top view of a therapeutic microtron device according to a first embodiment of the present invention.

2 is a side view of the device in FIG. 1. FIG.

FIG. 3 is a schematic cross-sectional view showing the internal structure of the microtron electron accelerator in the above embodiment.

FIG. 4 is a top view after switching the therapeutic gantry in the above embodiment.

FIG. 5 is a top view of a therapeutic microtron device according to a second embodiment of the present invention.

FIG. 6 is a schematic sectional view of a conventional therapeutic microtron device.

FIG. 7 is a top view of a conventional 2-gantry type therapeutic microtron device.

[Explanation of symbols]

 1 Microtron Electron Accelerator 2 Rotation Support 3, 3a, 3b Irradiation Head 4, 4a-4d Treatment Gantry 5, 5a-5d Quadrupole Electromagnet 6, 6a-6d Vacuum Pipe 7, 7a, 7b Treatment Table 8 Beam Extraction Pipe 9, 9a to 9d Vacuum valve 10 Accelerating cavity 11 Electromagnet 111 Magnetic pole 112 Yoke 113 Excitation coil 12 Electron gun 13 Magnetic shield pipe 14 Vacuum vessel 15, 15a, 15b, 15s Deflection electromagnet 16 Electronic orbit

Front page continued (72) Inventor Masatoshi Nishimura 1-1-14 Kanda, Chiyoda-ku, Tokyo Inside Hitachi Medical Co., Ltd.

Claims (3)

[Claims] 1. A therapeutic Microtron apparatus for treating a patient by irradiating a patient with an electron beam accelerated by a Microtron electron accelerator as it is or by converting it into X-rays and irradiating the patient with the electron beam. For rotating the microtron electron accelerator by rotating the microtron electron accelerator, and a means for rotating the same, a plurality of treatment gantry, and an electron beam transfer means arranged corresponding to the plurality of treatment gantry. A therapeutic microtron device characterized in that the therapeutic gantry to which an electron beam is transported is switched by changing the direction. 2. The therapeutic microtron device according to claim 1, wherein a circular microtron is used as the microtron electron accelerator. 3. The means for mechanically rotating the microtron electron accelerator is arranged so that the electron orbital plane of the microtron electron accelerator always exists in one horizontal plane. The therapeutic microtron device according to claim 1 or 2.