JPS632608B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a computer tomography apparatus, and more particularly to a computer tomography apparatus capable of acquiring a large number of tomographic images in a short period of time.

Computerized tomography devices have been developed in recent years, but in this type of device, an X-ray source and an X-ray detector are rotated around the subject (patient), and the subject is irradiated with X-rays from each direction. The intensity is measured and the obtained data is processed by a computer to obtain a tomographic image of the subject. At the stage of using this device, the X-ray source and X-ray detector are moved in the direction of the patient's body axis to obtain multiple tomographic images, which are useful for diagnosis. Therefore, it is relatively heavy and has a large moment of inertia
It takes a long time to rotate and move the radiation source, etc.
Therefore, the subject changes during data acquisition, making it difficult to accurately compare and observe a plurality of obtained tomographic images, and the pain that long-term measurements cause to the patient cannot be ignored. Therefore, as shown in FIG. 1, the subject 1 is narrowed down and the X-ray source 2 and the subject 1
a plurality of X-ray detectors 3a arranged in the body axis direction,
3b...3n, the X-ray source and the X-ray detector are rotated once around the subject 1, and a large number of data are obtained simultaneously by each detector, and the data obtained for each detector is A method is conceivable in which a plurality of tomographic images are obtained by processing the information. However, although this method can measure the data necessary to obtain multiple tomographic images in a relatively short time, for example, the X-ray detector 3a
Alternatively, X-rays are obliquely incident on 3n, and these X-rays
Even if lines are detected and processed, a tomographic image perpendicular to the body axis of the subject 1 cannot be accurately obtained.

The present invention has been made in view of the above points, and involves rotating an X-ray generating section having a length in the direction of the subject's body axis around the subject, and transmitting the X-rays generated from the X-ray generating section along the subject's body axis. A plurality of X-ray beams are projected onto a subject as a plurality of X-ray beams perpendicular to
It is detected by a group of line detection elements,
To provide a computer tomography device capable of acquiring a plurality of accurate tomographic images perpendicular to a subject axis in a short time.

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

In FIG. 2, 11 is a bell-shaped X-ray source column, and one end of the column 11 is provided with an electron beam generation source 12, and the other end is provided with an annular X-ray generation target 13. ing. The electron beam source 1
The electron beam generated from 2 and accelerated is deflected by the deflection coil 1.
4. The beam is deflected by the deflection plate 15 and irradiated onto the target 13. X-rays are generated by irradiating the target 13 with the electron beam, and the X-rays are projected toward the subject 16 inserted into the hollow portion of the bell-shaped column 11. Here, the shape of the electron beam image on the target 13 seen from the subject 16 is elongated in the body axis direction of the subject, and the electron beam irradiation section (X-ray generation section) on the target 13 supplies the electron beam image to the deflection coil 14. It moves over the target and rotates around the subject 16 by changing the deflection signal applied to it. An annular collimator 17 is arranged inside the target 13, and the X-rays generated from the target 13 are directed to the object 1 by the collimator 17.
A plurality of X-ray beams perpendicular to the body axis of the subject 16 are projected onto the subject 16. In order to detect a plurality of X-ray beams transmitted through the object 16, eight detector blocks 1 are arranged around the object 16 as shown in FIG.
8A, 18B...18H, each detector block 18 is placed in or removed from the X-ray beam path by a respective motor 19. The detector block 1
8 consists of a large number of X-ray detection elements 20, and in each block, the number of X-ray detection elements equal to the number of multiple X-ray beams is arranged in the direction of the subject axis, and the body axis is For example, 32 X-ray detection elements are arranged in a ring shape in the vertical direction. As a result, if the number of X-ray beams is 10, each detector block 18 is composed of 320 X-ray detection elements 20.

In the above-described configuration, the accelerated electron beam generated from the electron beam source 12 is deflected by the deflection coil 14 and the deflection plate 15 to form an elongated image in the axial direction of the subject on the X-ray generation target 13. As a result, the X-ray generating portion on the target 13 becomes elongated in the direction of the object axis. The X-rays generated from the target 13 are converted into a plurality of beams perpendicular to the body axis of the subject 16 by a collimator 17, and each of the X-ray beams is directed toward the subject 16 as a fan-shaped beam that spreads in a direction perpendicular to the plane of the paper. Projected. Here, the detector blocks 18C, 18D, 18E, 1
8F is moved (retracted) by a motor 19 from inside the annular locus of the X-ray generating section P in the direction of the body axis of the subject 16 so as not to interfere with the projection of the X-ray beam onto the subject 16. The detector blocks 18A, 18B, 18G, and 18H are arranged inside the trajectory to detect the X-ray beam transmitted through the object 16. As the X-ray generator P rotates in the direction of the arrow shown in FIG.
8G is retracted from inside the trajectory and detector block 18C is placed inside the trajectory.

In this way, while the X-ray generator P makes one rotation around the subject 16, each detector block is moved according to the position of the X-ray generator P, and a plurality of X-rays perpendicular to the body axis of the subject are detected. The beam is simultaneously detected by a number of X-ray detection elements forming a detector block. The signals detected by the X-ray detection element are processed by a computer (not shown) for each X-ray beam, and a plurality of tomographic images are obtained.

As detailed above, in the present invention, multiple X-ray beams perpendicular to the body axis are simultaneously projected onto the subject and the transmitted X-rays are detected, so the obtained tomographic image is extremely accurate. becomes.
In addition, the detector block is selectively moved in the direction of the subject's axis, but since the movement of this block is not accompanied by centrifugal force, even if the block is moved at high speed, the acceleration force applied to the block is small and the time is extremely short. It is possible to acquire the data necessary to obtain multiple tomographic images in one time. Note that the present invention is not limited to the embodiments described above, and can be modified in many ways. For example, instead of forming an elongated electron beam image on the X-ray generating target, the electron beam is focused narrowly on the target, and the irradiation point of the electron beam is moved on the target at high speed in the direction of the subject's body axis, thereby effectively covering the body of the subject. An X-ray generating portion having a length in the axial direction may be formed. Furthermore, although the annular target is used to rotate the X-ray tube around the subject by deflecting the electron beam that irradiates the target with the X-ray generating section, an ordinary X-ray tube may also be rotated around the subject.

Note that the structure expressed by the word cyclic in this specification includes not only a complete ring but also the shape of a part of the ring.

[Brief explanation of the drawing]

Figure 1 is a diagram for explaining the conventional device, Figure 2 is a diagram for explaining the conventional device.
The figure shows an embodiment of the present invention. FIG. 3 is a diagram showing a detector block used in the apparatus shown in FIG. 11: Bell-shaped column, 12: Electron beam source, 1
3: X-ray generation target, 14: Deflection coil, 1
5: Deflection plate, 16: Subject, 17: Collimator,
18A-H: Detector block, 19: Motor, 2
0: X-ray detection element.

Claims (1)

[Claims] 1 It has an electron beam generation source and an annular X-ray generation target that is irradiated with an electron beam from the electron beam generation source and placed around the subject, and the X-ray generation part on the X-ray generation target is substantially an X-ray source having a length generally in the axial direction of the subject; a means for moving an electron beam irradiation unit on the target such that the X-ray generating unit on the target rotates around the subject; A means for converting the X-rays generated from the generating part into a plurality of X-ray beams perpendicular to the subject axis, and a means for converting the X-rays generated from the generating part into a plurality of X-ray beams perpendicular to the subject axis; A group of X-ray detection elements arranged in a matrix in an annular direction, the number of X-ray detection elements in the subject axis direction corresponding to the number of the plurality of X-ray beams. and means for selectively retracting or arranging the group of X-ray detection elements from inside the annular locus of the X-ray generating section.