JPH0381381B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tomography apparatus that irradiates a living body or the like with X-rays and takes a tomographic image of the living body or the like based on an X-ray fluoroscopic image.

[Conventional technology]

Generally, medical tomography equipment (hereinafter referred to as X-ray CT
As shown in FIG.
is rotated by a driving means as shown by the arrow in the same figure, the living body is irradiated with X-rays from the circumferential direction, and the X-rays that have passed through the living body are detected by a plurality of detectors 2,
A tomographic image of a living body is created and displayed based on an X-ray fluoroscopic image of the living body.

[Problem that the invention seeks to solve]

However, in this type of X-ray CT, since the heavy X-ray generating means 1 is mechanically rotated, the driving means for rotating the generating means 1 becomes large in size, and moreover, a large burden is placed on the driving means. Generating means 1
There is a problem in that it is not possible to increase the rotational speed to a certain level, and it is not possible to increase the speed of photographing.

Therefore, the present invention aims at speeding up imaging by changing the direction of irradiation of X-rays onto an irradiated object in a short time.

[Means for solving problems]

The present invention includes: a substantially annular vacuum chamber in which a space for irradiating objects is formed in the center; an X-ray irradiation window formed in a substantially annular shape on the inner surface of the vacuum chamber;
A target for generating X-rays provided in the vacuum chamber, an electron beam injection means for injecting electrons into the vacuum chamber, and a magnetic field for deflecting the incident electrons into a circular orbit along the vacuum chamber by a magnetic field. generating means; irradiation means for colliding an electron beam with the target to generate X-rays from the target and irradiating the X-rays from each point of the irradiation window to the center of the space; The present invention is a tomography apparatus characterized by comprising a photographing means for obtaining a line tomographic image.

[Effect]

Next, to explain the operation of this invention,
The orbit of the electron beam is deflected into a circular orbit by the magnetic field generated by the magnetic field generation means, and the deflected electron beam collides with the target by the irradiation means, and X-rays are irradiated from each point of the approximately annular irradiation window. The direction of irradiation of the beam onto the object to be irradiated can be changed easily and in a short time by the irradiation means.

〔Example〕

Next, FIGS. 1 to 6 showing embodiments of the present invention will be explained.

First, FIGS. 1 to 4 showing one embodiment will be explained.

Now, to explain the operating principle according to the schematic diagram in Figure 1, as shown in the figure, an electron beam (EB) is emitted in a direction perpendicular to a downward uniform magnetic field H perpendicular to the plane of the paper.
When irradiated from the electron beam incidence means 3, the electrons are subjected to a Lorentz force in a direction perpendicular to the magnetic field and the direction of travel, which is proportional to the strength of the magnetic field and the velocity of the electrons, so the electron beam (EB) is focused at one point in the figure. If the electron beam (EB) is deflected into a circular orbit as shown by the chain line and a target 4 of molybdenum or the like is placed on this circular orbit, the deflected electron beam (EB) collides with the target 4 and X-rays 5 are emitted from the target 4. generated.

In FIGS. 2 to 4 showing the configuration of an X-ray CT that generates X-rays and performs tomography of a living body, etc. according to the operating principle described above, 6 is a frame body;
Reference numeral 9 indicates a stainless steel casing consisting of a substantially annular vacuum chamber 8 placed on a frame 6 and having a space 7' in which an irradiated object such as a living body (not shown) is placed; 9 is a casing; 10 is a vacuum pump that is airtightly connected to the connecting pipe 9 to create a vacuum inside the housing 7; 11 is integrally formed on the front end of the right side of the housing 7; An electron beam (EB) is provided parallel to the tangential direction of the center circle of the vacuum chamber 8 and is connected to the electron beam incidence means 3 shown in FIG.
12 is an electron beam absorbing section airtightly provided at the rear end of the right side of the housing 7, and 13 is an irradiation window, which is located almost on the inner surface of the vacuum chamber 8 of the housing 7, that is, on the side of the irradiated object. It is formed into an annular shape and is hermetically closed by an aluminum plate 14.

15 is a fixed body fixedly provided in the vacuum chamber 8, and 16 is a ring-shaped turntable which is an irradiation means made of gears, and is rotatably provided on the fixed body 15 via a bearing 17, as shown in FIG. A target 4 shown in the figure is placed, and as the turntable 16 rotates, the electron beam (EB) from the generation means 3 via the incident pipe 11 or the magnetic field from the magnetic field generation means described later is deflected to a position where it collides with the target 4. is changed, and X-rays are irradiated from each point of the irradiation window 13 to the center of the space 7'.

Reference numeral 18 is airtightly connected to the right rear end of the lower surface of the casing 7, and a motor housing 19 housing a motor for rotating the turntable 16 is pivotally attached to the rotation shaft of the motor and meshes with the teeth of the turntable 16. A drive gear that rotates the turntable 16 by the rotation of the motor; 20 is a yoke with a U-shaped cross section that covers the left half of the housing 7; 21 and 22 are yoke 20;
Arc-shaped upper and lower cores 23 and 24 formed along the vacuum chamber 8 inside the upper and lower surfaces respectively are upper and lower coils, and both cores 21 and 22 respectively.
When viewed from above, the outside is energized clockwise and the inside is energized counterclockwise, forming a downward magnetic field in the vertical direction within the vacuum chamber 8.
The electron beam (EB) is deflected into a circular orbit approximately concentric with the vacuum chamber 8, as shown by the dashed-dotted line arrow in FIG.
3 and 24 constitute a magnetic field generating means 25.

Although not shown, a plurality of X-ray detectors for detecting X-rays passing through the irradiated object are provided, and the irradiated object is Photographing means is provided for creating and displaying a tomographic image of the irradiator.

By passing current through both coils 23 and 24, a uniform magnetic field is formed within the vacuum chamber 8, and an electron beam (EB) is introduced into the vacuum chamber 8 from the electron beam input means 3 through the input pipe 11. When it enters,
The incident electron beam (EB) is deflected into a circular orbit by the Lorentz force caused by the magnetic field, the deflected electron beam (EB) collides with the target 4 and generates X-rays, and the generated X-rays enter the irradiation window. The irradiated object placed in the space 7' is irradiated via the beam 13.

At this time, when the gear 19 is rotated by the motor and the turntable 16 is rotated, the target 4 is rotated.
The position of the electron beam (EB) is changed, and the collision position of the electron beam (EB) deflected into a circular orbit by the magnetic field with the target 4 is changed, so that the direction of irradiation of the X-rays to the irradiated object through the irradiation window 13 is changed. It turns out.

In addition, instead of the target 4 and turntable 16 in FIG. 1, the circular orbit of the electron beam (EB), that is, the center line of the vacuum chamber 8, is irradiated upward and downward as shown in FIGS. 5 and 6. A plurality of auxiliary air-core coils 26 are arranged as means, and a plurality of targets 27 are arranged outside each air-core coil 26.
An air core coil 26 located inside the target 27 with which you want to collide the electron beam (EB).
5, the upper and lower coils 2
3 and 24, a local magnetic field in the opposite direction to that of the magnetic field is generated by the air-core coil 26 in the magnetic field generated by the generating means 25,
The electron beam (EB) deflected into a circular orbit by the magnetic field generated by the generating means 25 is further deflected to the outside of the circular orbit by the local magnetic field and collides with the target 27, generating X-rays. By sequentially switching the air-core coils 26 through which current is passed, the target 27 with which the electron beam collides is
is changed, and the irradiation direction of the X-rays irradiated onto the irradiated object through the irradiation window 13 is changed.

Further, a permanent magnet may be used as the magnetic field generating means 25.

〔Effect of the invention〕

Therefore, according to the present invention, the direction of irradiation of X-rays onto an irradiated object can be changed simply by changing the position of the target 4 using the turntable 16 or by sequentially switching the air-core coils 26 to which current should be passed. In particular, in the first embodiment, instead of rotating a heavy X-ray generator as in the conventional case, a lightweight target is rotated together with the turntable 16, which greatly reduces the load on the motor. By rotating the target 4 at high speed, the direction of irradiation of the X-rays onto the irradiated object can be changed easily and in a short time.
The speed of photographing can be increased, and the effect is remarkable.

Furthermore, since there is no mechanically rotating part in the second embodiment, the direction of irradiation of X-rays can be changed at higher speed, and the performance can be stabilized.

Moreover, it can be applied not only to tomography apparatuses but also to other X-ray generating apparatuses, and its usefulness is extremely large.

[Brief explanation of drawings]

1 to 6 show an embodiment of the tomography apparatus of the present invention, and FIGS. 1 to 4 are a schematic diagram, a plan view, a partially cut right side view, and a right side view of one embodiment, respectively. , FIG. 5 and FIG. 6 are schematic diagrams and side views of other embodiments, and FIG. 7 is a schematic diagram of a conventional tomography apparatus. 3... Electron beam incidence means, 4, 27... Target, 8... Vacuum chamber, 13... Irradiation window, 16...
... Turntable, 21, 22 ... Core, 23,
24... Coil, 25... Magnetic field generating means, 26...
...Air core coil.

Claims (1)

[Claims] 1. A substantially annular vacuum chamber in which a space in which an irradiated object is placed is formed in the center, an X-ray irradiation window formed in a substantially annular shape on the inner surface of the vacuum chamber, and an X-ray irradiation window provided in the vacuum chamber. a target for generating X-rays; an electron beam injection means for injecting electrons into the vacuum chamber; a magnetic field generation means for deflecting the incident electrons into a circular orbit along the vacuum chamber by a magnetic field; irradiation means for causing an electron beam to collide with the target to generate X-rays from the target and irradiating the X-rays from each point of the irradiation window to the center of the space; and an X-ray tomographic image of the irradiated object. What is claimed is: 1. A tomography apparatus comprising: a means for obtaining an image;