JPH0576524A - X-ray ct device - Google Patents

Abstract

PURPOSE:To prevent data from being missed or the interference of X rays from being generated at various angles even when a two-dimensional detector is adopted as an X-ray detector. CONSTITUTION:This device is equipped with an X-ray generating source 1 to successively linearly move the generating position of X rays, two-dimensional detector 2 to detect X rays by a detecting element group 5 arranged parallelly to the X-ray generating source 1, and control means 4, 7 and 9 to execute control for synchronizing the detecting position of X rays to the generating position of X rays, and a collimator 19 is provided on the side of the two-dimensional detector 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray CT apparatus for reconstructing a tomographic image of a subject based on data collected by irradiating the subject with X-rays.

[0002]

2. Description of the Related Art Conventionally, this type of X-ray CT apparatus has adopted a one-dimensional detector as an X-ray detector. In this case, 1
Since the projection data for one scan is two-dimensional data, only one tomographic image can be reconstructed for each scan. However, when a two-dimensional detector is used as the X-ray detector, the projection data for one scan becomes three-dimensional data, so that it is possible to reconstruct a plurality of tomographic images for each scan. Becomes Therefore, it has been considered that a two-dimensional detector is adopted as the X-ray detector so as to shorten the imaging time.

[0003]

However, when a subject is irradiated with X-rays in a cone-beam shape, the X-rays do not pass through the subject in a portion near the X-ray generation source, so that the projection data is Data loss may occur. Further, when the X-ray is irradiated in parallel beam form on the subject, it is possible to prevent the data loss in the projection data, but since the X-ray detector is two-dimensional, it is possible to use various angles. X
Accurate projection data cannot be obtained because the lines interfere with each other. Therefore, in the conventional case, it was not possible to obtain a highly accurate tomographic image with the X-ray CT apparatus employing the two-dimensional detector.

The present invention has been made in order to solve the above-mentioned problems of the prior art.
An object of the present invention is to provide an X-ray CT apparatus that can prevent data loss and interference of X-rays from various angles even if a two-dimensional detector is used as the line detector.

[0005]

An X-ray generation source capable of sequentially linearly moving an X-ray generation position, and an X-ray detection unit for detecting X-rays arranged in parallel with the X-ray generation source. It is characterized by comprising a detector and control means for performing control for synchronizing the X-ray generation position with the X-ray generation position. Further, a collimator is provided on the X-ray detector side,
The X-ray detector is a two-dimensional detector.

[0006]

In the X-ray CT apparatus of the present invention having the above construction, the X-ray CT of the subject is converted into a parallel beam by an X-ray generation source.
Since the line is exposed, data loss can be avoided. Further, when the X-rays are emitted in the form of parallel beams as described above, the X-ray generation position in the X-ray generation source and the X-ray detection position in the X-ray detector are synchronized by the control means,
Even if the X-ray detector is a two-dimensional detector, only parallel beam components are collected as projection data. In particular,
If the collimator is provided on the X-ray detector side and only the parallel beam is selectively passed, it is possible to collect only the parallel beam component as projection data with higher accuracy.

[0007]

An embodiment of the present invention will be described below with reference to the drawings. 1 is a block diagram showing an outline of an X-ray CT apparatus to which the present invention is applied, FIG. 2 is a block diagram showing an X-ray generation source and an X-ray controller in the X-ray CT apparatus of the present invention, and FIG. FIG. 4 is a configuration diagram showing a detector, and FIG. 4 is a configuration diagram showing a two-dimensional detector provided with a collimator.

In FIG. 1, an X-ray generation source 1 and a two-dimensional detector 2 are arranged so as to face each other with a subject P interposed therebetween. Then, in the X-ray generation source 1, the X-ray generation position on the linear target 3 is deviated in time, a, b, ...
It is controlled by the X-ray controller 4 so as to move linearly like j. On the other hand, the two-dimensional detector 2
Is a two-dimensional detection of X-rays generated from the X-ray generation source 1 by a detection element group 5 arranged in parallel with the X-ray generation source 1. It is done by operation. The synchronization controller 9 in the system control unit 8 receives the timing of X-ray generation controlling the X-ray controller 4, and the synchronization controller 9 controls the data acquisition controller 7 to control the X-ray generation position a in the X-ray generation source 1. , B, ..., J and X-ray detection positions a ′, b ′, ..., J ′ in the two-dimensional detector 2 are synchronized. At the same time as performing these operations, the gantry rotation control unit 1
0 receives a signal from the system control unit 8 and controls the rotation of the gantry. Note that the collected projection data is A / D converted by the data collection unit 6 and then sequentially transferred to the image reconstruction unit 11 for image reconstruction, and based on the plurality of tomographic images reconstructed here. A three-dimensional image or the like is displayed on the monitor 12.

In FIG. 2, the X-ray controller 4 is an X-ray controller.
It is provided with a high voltage generator 13 for generating a high voltage in the line source 1, an electron beam controller 14, a deflection coil controller 15, and an X-ray controller 16 which controls these and also serves as an interface. Then, the electron beam control unit 14 controls the electron gun 17 to generate an electron beam, and the deflection coil control unit 15 controls the deflection coil 18 to deflect the electron beam, thereby sequentially generating X-ray generation positions. It is a structure that can be moved. Also, the tube voltage,
The X-ray condition such as the tube current is controlled by a signal from the system controller 8.

As shown in FIG. 3, the two-dimensional detector 2 has detection elements arranged two-dimensionally to form a detection element group 5, and the X-rays from the X-ray source 1 are two-dimensionally arranged. Can be detected. Further, as shown in FIG. 4, collimators 19 are provided in a grid pattern on the front surface of the two-dimensional detector 2 in order to enhance directivity so that only X-rays from the X-ray generation source 1 are detected.

With such a configuration, the X-ray generation timing for controlling the X-ray controller 4 is received by the synchronization controller 9, and the data acquisition controller 7 is controlled by the synchronization controller 9, whereby the X-ray generation at the X-ray generation source 1 is performed. , J and the X-ray detection positions a ′, b ′, ..., j ′ in the two-dimensional detector 2 are synchronized. When performing scanning, as shown in FIG. 5, the X-ray generation position is sequentially moved to a, b, ..., J every time a gantry (not shown) rotates by a small angle, for example, 0.6 °. This operation is repeated a plurality of times while the gantry rotates 360 °. The projection data thus collected is subjected to image reconstruction in the image reconstruction unit 11, and a three-dimensional image or the like is displayed on the monitor 12 based on the plurality of tomographic images reconstructed here.

Regarding the arrangement of the X-ray generation source 1 and the two-dimensional detector 2 on the mount, a third generation, a fourth generation, a method of rotating the subject P, or the like is possible. In the case of the third generation, the configuration is as shown in FIGS. 6A and 6B, and the gantry 20 is continuously rotated and the X-ray generation positions are a, b, ..., J, a. , B, ..., J can be repeatedly collected to continuously collect data during rotation of the gantry 20. Moreover, since the two-dimensional data can be collected by one scan, the gantry rotation speed can be slowed down as compared with the X-ray CT apparatus using the one-dimensional detector. Therefore, for example, a gantry rotation speed of about 10 seconds / revolution is sufficiently practical, and the load on the gantry rotation system can be reduced. Further, for the same reason, the method of rotating the subject P is also practical.

Therefore, according to this embodiment, even if a two-dimensional detector is used as the X-ray detector, it is possible to prevent data loss and interference of X-rays from various angles with high accuracy. The image can be reconstructed.

[0014]

The X-ray CT apparatus of the present invention has the above-described structure and operation. By exposing X-rays in the form of parallel beams, data loss is prevented and X-ray detection is performed at the X-ray generation position. More accurate data can be collected by synchronizing the positions to avoid interference of X-rays from various angles. In this way, data collection by parallel beams can be realized, and a plurality of tomographic images can be reconstructed for each scan. Further, by providing a collimator on the X-ray detector side, it is possible to collect only parallel beam components as projection data.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an X-ray CT apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an X-ray generation source and an X-ray controller in an X-ray CT apparatus according to an embodiment of the present invention.

FIG. 3 is a configuration diagram showing a two-dimensional detector in an X-ray CT apparatus according to an embodiment of the present invention.

FIG. 4 is a configuration diagram showing a two-dimensional detector including a collimator in the X-ray CT apparatus according to the embodiment of the present invention.

FIG. 5 is a diagram showing a relationship between a gantry rotation angle and an X-ray generation position in the X-ray CT apparatus according to the embodiment of the present invention.

FIG. 6A is a third generation X-ray C to which the present invention is applied.
The front view which shows T device, (b) is a side view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 X-ray generation source 2 Two-dimensional detector (X-ray detector) P Object 4 X-ray controller (control means) 5 Detection element group 7 Data acquisition controller (control means) 9 Synchronous controller (control means) 19 Collimator

Claims (3)

[Claims] 1. An X-ray generation source capable of sequentially linearly moving an X-ray generation position, and an X-ray detector for detecting X-rays by a detection element group arranged in parallel to the X-ray generation source. An X-ray CT apparatus, comprising: a control unit that controls to synchronize the X-ray detection position with the X-ray generation position. 2. The X-ray CT apparatus according to claim 1, further comprising a collimator on the X-ray detector side. 3. The X-ray CT according to claim 1, wherein the X-ray detector is a two-dimensional detector.
apparatus.