JP2000308690A - Medical microtron - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the height of a microtron electronic accelerator settable low by providing a medical microtron with a means for emitting an electron beam from the microtron electronic accelerator upward obliquely to a horizontal plane and with an electromagnet for deflecting electron beams emitted upward obliquely in the horizontal direction. SOLUTION: An electron gun 9 is attached to an accelerating cavity 8 of a microtron electronic accelerator 1, and electrons emitted from the electron gun 9 are accelerated to reach a desired energy. The accelerated electron is let offset from a circular orbit by a magnetic shield pipe 10 disposed on a circular orbit to be taken out to the outside of the accelerator 1 at an angle of 40 deg. to the horizontal plane by an electron beam take-out pipe 11, and the taken out electrons are deflected in the horizontal direction by a deflecting electromagnet 3a with a deflecting angle of 40 deg., an then focused and deflected by quadrupole electromagnets 2a-2c or deflecting electromagnets 3b-3d to be transported to an irradiation head 5 and be applied to a patient on a treatment table 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical microtron for treating a patient using an electron beam accelerated by a microtron electron accelerator, and more particularly, to a medical microtron having a structure that can be installed at a low height. .

[0002]

2. Description of the Related Art A medical microtron is a device mainly used for cancer treatment, which irradiates a patient with an electron beam accelerated by a microtron electron accelerator as it is or converts it into an X-ray.

The configuration of a conventional medical microtron will be described with reference to FIG. The apparatus mainly includes a microtron electron accelerator 1 for accelerating electrons, an electron beam transport system for transporting an electron beam accelerated by the accelerator 1, and an irradiation head 5 for irradiating a patient with an electron beam or X-ray. And a treatment table 7 on which a patient is placed.

The microtron electron accelerator 1 arranges an accelerating cavity 8 for generating a high-frequency accelerating electric field by the input of a microwave in a uniform magnetic field, and sequentially moves the electron to a high orbital motion by the magnetic field and the electric field. A device that accelerates to energy. The accelerator 1 is installed so that its electron orbit plane is perpendicular to the horizontal plane in order to reduce the installation floor area. The accelerated electron beam is removed from the circular orbit by the magnetic shield pipe 10 and is emitted outside the accelerator.

The electron beam transport system comprises quadrupole electromagnets 2a to 2c for focusing the electron beam, deflection electromagnets 3b to 3d for deflecting the electron beam, and a vacuum pipe 4 for passing the electron beam. Transports the electron beam emitted from the accelerator 1 to the irradiation head 5 in the therapeutic gantry 6. Further, the treatment gantry 6 is configured to be rotatable, and can irradiate a patient with an electron beam or an X-ray from various angles. Reference numeral 9 denotes an electron gun for emitting electrons, 10
Is a magnetic shield pipe.

The above prior art is described in "Medical Imaging and Radiology Equipment Handbook" (1989), pp. 200-205, edited by the Japan Radiological Equipment Manufacturers Association.

[0007]

In the above prior art, an electron beam is emitted horizontally from a microtron electron accelerator. Therefore, the height at which the electron beam exits is
It is the same as the height of the isocenter (about 1250 mm).
The outer diameter of a microtron electron accelerator having a maximum energy of 20 MeV is 2000 mm or more. Therefore, in the prior art, the installation height H of the microtron electron accelerator is 3000 mm or more, and the height of the entrance is 3 mm.
When installed in a room of 000 mm or less, the entrance and exit must be significantly modified.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is an object of the present invention to provide a medical microtron which can be easily installed even in a room having an entrance height of 3000 mm or less by reducing the installation height. With the goal.

[0009]

An object of the present invention is to provide a medical microtron 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 an X-ray. Means for setting the electron orbital surface of the microtron electron accelerator so as to be perpendicular to the horizontal plane, and for emitting the electron beam from the microtron electron accelerator obliquely upward with respect to the horizontal plane, This is achieved by providing an electromagnet that deflects the emitted electron beam in the horizontal direction. The electron beam is emitted from the microtron electron accelerator at an angle of 10 to 60 degrees with respect to a horizontal plane. This makes it possible to realize a medical microtron whose installation height is lower than that of the prior art.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view of a medical microtron according to a first embodiment of the present invention, and FIG. 2 is a top view thereof. The medical microtron according to the present embodiment is mainly composed of a columnar microtron electron accelerator 1.
(Diameter: 2200 mm, thickness: 500 mm, weight: about 1
0t), quadrupole electromagnets 2a-2c and deflection electromagnets 3a-3
an electron beam transport system comprising an electron beam and X
It comprises a treatment gantry 6 having an irradiation head 5 for irradiating a patient with a line, and a treatment table 7 on which the patient is placed.

Next, a schematic configuration of the microtron electron accelerator 1 will be described. The accelerating cavity 8, which creates a high-frequency accelerating electric field by the input of microwaves (3 GHz), has a uniform magnetic field (0.
11T) is provided in the electromagnet. An electron gun 9 is attached to the acceleration cavity. A movable magnetic shield pipe 10 is provided in the uniform magnetic field, and an electron beam extraction pipe 11 is provided at an electron beam exit at an angle of 40 degrees with respect to a horizontal plane.

Next, the operation of this embodiment will be described with reference to FIG. The electrons emitted from the electron gun 9 are guided into the acceleration cavity 8 and accelerated, and re-enter the acceleration cavity 8 after drawing a circular orbit in a uniform magnetic field by an electromagnet. Here, the electrons are further accelerated, and re-enter the acceleration cavity 8 in a larger circular orbit. This operation is repeated, and the electrons are accelerated until the desired energy is reached. The electrons accelerated to the desired energy are removed from the circular orbit by the magnetic shield pipe 10 arranged on the circular orbit, and extracted outside the accelerator 1 at an angle of 40 degrees with respect to the horizontal plane by the electron beam extraction pipe 11. It is. The extracted electrons are deflected in the horizontal direction by a deflection electromagnet 3a having a deflection angle of 40 degrees,
Then, the quadrupole electromagnets 2a to 2c and the bending electromagnets 3b to 3c
The light is focused and deflected by d and is conveyed to the irradiation head 5. Then, the patient is irradiated with the electron beam as it is or converted into X-rays on the treatment table 7.

By the way, in the microtron electron accelerator 1 of this embodiment, the acceleration energy of the electron in the accelerating cavity 8 per one time is 0.525 MeV, and the energy of the electron in the n-th circular orbit is 0.525 ( n + 1) -0.51
1 MeV. Although the maximum number of orbits is shown in FIG. 1 for only 14 turns, it can actually be accelerated to 40 turns. Therefore, by moving and positioning the magnetic shield pipe 10 on each circular orbit (8 to 40 turns), 0.5 to 0.5
An electron beam having an energy of every 25 MeV is obtained.

As described above, the electron beam emitted from the electron gun is taken out of the accelerator 1 at an angle of 40 degrees with respect to the horizontal plane by the pipe 11 for taking out the electron beam. Can be lower than before. Specifically, as shown in FIG. 1, the installation height H of the microtron electron accelerator 1 in the present embodiment is 2300 mm, which can be significantly reduced as compared with the conventional height of 3000 mm or more. Further, the therapeutic gantry 6 in the present embodiment.
Is 2500 mm, the installation height of the entire apparatus is also 2500 mm.

That is, in the present embodiment, the installation height of the apparatus can be made substantially equal to the installation height of another medical accelerator (medical linear accelerator). Since the prior art medical microtron has a high installation height, if it is installed in an existing room in a hospital, it needs to be remodeled to increase the height of the entrance of the room, but in the present invention, it is done so There is no necessity, and the apparatus configuration of this embodiment is extremely useful.

Next, a second embodiment of the present invention will be described with reference to FIGS.
This will be described below. FIG. 3 is a schematic sectional view of a medical microtron, and FIG. 4 is a top view thereof. In the present embodiment, the arrangement of the treatment gantry 6 is changed by 90 degrees with respect to the first embodiment. In the case of the present embodiment, the deflection angle of the electron beam in the bending electromagnet 3a is
It is 90 degrees regardless of the emission angle of the electron beam from. In this embodiment, the overall length of the device can be shortened, but the overall width is wider than in the first embodiment. Depending on the shape of the room, this embodiment may be more suitable.

Next, a third embodiment of the present invention will be described with reference to FIG. This embodiment is different from the first embodiment in that the position of the accelerating cavity 8 and the electron gun 9 is changed and the electron beam is directly extracted from the electron beam extraction pipe 11 so that the movable magnetic shield pipe 10 is omitted. This is a configuration in which: In the present embodiment, only a single energy electron beam can be obtained, but the configuration of the device can be simplified.

The embodiments of the present invention have been described above.
The present invention is not limited to the above-described embodiment, and various configurations as described below are possible. For example, in the first embodiment, the specifications of the microtron electron accelerator 1 are set so that the maximum number of orbits is 40 turns and the maximum energy is 21M.
eV, uniform magnetic field strength: 0.11 T, diameter: 2200 m
m, thickness: 500 mm, but this may be any number of orbits, energy, magnetic field strength, and dimensions. In the first embodiment, the emission angle of the electron beam from the microtron electron accelerator 1 with respect to the horizontal plane is set to 40 degrees. However, this may be set to, for example, 30 degrees. In short, any angle may be used as long as the installation height of the microtron electron accelerator 1 can be made lower than in the related art. In the above embodiment, the deflection electromagnet 3a for deflecting the electron beam emitted obliquely upward from the microtron electron accelerator 1 in the horizontal direction is one.
Although it is composed of two pieces, it may be composed of two pieces, for example.

[0020]

According to the present invention, since the installation height of the microtron electron accelerator can be reduced, a medical microtron having a low installation height can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a medical microtron according to a first embodiment of the present invention.

FIG. 2 is a top view of the first embodiment.

FIG. 3 is a schematic sectional view of a medical microtron according to a second embodiment of the present invention.

FIG. 4 is a top view of the second embodiment.

FIG. 5 is a schematic sectional view of a medical microtron according to a third embodiment of the present invention.

FIG. 6 is a schematic sectional view of a conventional medical microtron.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Microtron electron accelerator 2a-2c Quadrupole electromagnet 3a-3d Bending electromagnet 4 Vacuum pipe 5 Irradiation head 6 Treatment gantry 7 Treatment table 8 Acceleration cavity 9 Electron gun 10 Magnetic shield pipe 11 Electron beam extraction pipe

Claims (1)

[Claims] 1. A medical microtron for irradiating a patient with an electron beam accelerated by a microtron electron accelerator or converting it into an X-ray and irradiating a patient with the electron beam, an electron orbital surface of the microtron electron accelerator. Is installed so as to be perpendicular to the horizontal plane, means for emitting the electron beam from the microtron electron accelerator obliquely upward with respect to the horizontal plane, and the electron beam emitted obliquely upward in the horizontal direction. And a deflecting means.