JPH055781A - Detector for x-ray ct - Google Patents

Abstract

PURPOSE:To easily adjust resolving power and to enhance the resolving power in low cost by making a scintillator processable by conventional processing technique without unreasonally reducing the scintillator and shifting a collimator having a slit or correcting the processing thereof. CONSTITUTION:A detector for an X-ray CT is constituted of an X-ray tube 1 and the detection unit 2 consisting of a plurality of detection elements opposed to the X-ray tube 1 and an object 3 to be measured is arranged between the X-ray tube 1 and the detection unit 2 and the object 3 to be measured is rotated or the X-ray tube 1 and the detection unit 2 are rotated. First collimators 6a are arranged between the scintillators 5 arranged to the detection unit 2 and the separate scintillators 5 adjacent to said scintillators 5 and second collimators 6b having slits 4 to which the X-rays from an X-ray focus 7 can be incident are arranged to the fronts on the X-ray incident side of the scintillators 5, 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detector for X-ray CT for obtaining a tomographic image (CT image) of an oblique object by X-ray.

[0002]

2. Description of the Related Art A conventional X-ray CT detector is disclosed in Japanese Patent Laid-Open No.
There is a detector unit in which a plurality of detectors of JP-A-2-43585 are arranged. As shown in FIG. 8, a plate-shaped collimator 21 is present between the scintillators 20 so that the scintillators 20 do not enter the adjacent scintillator 20.

[0003]

However, in the conventional device, only the plate-like collimator 21 exists between the scintillators 20, and in order to make the conventional detection device have high resolution, the arrangement of the detection elements is changed. The scintillator 20 must be made small and the collimator 21 must be made thin, although it must be made fine. A single crystal is generally used for the scintillator 20, but there is a limit to processing it in a small size (a size of about 0.2 mm or less is desired, but with the current technology, processing up to about 0.7 mm is possible. However, if the collimator 21 is too thin, the original purpose of the collimator 21, which is to absorb scattered rays, is lost. Therefore, the conventional detection device has a problem that it is not suitable for high resolution. An object of the present invention is to solve the above problems.

[0004]

[Means for Solving the Problems] Technical means for achieving the above object include an X-ray tube, a detection unit composed of a plurality of detection elements opposed to the X-ray tube, the X-ray tube and the detection unit. A measurement object is arranged between the measurement object and, in the X-ray CT detection device for rotating the X-ray tube and the detection unit, the scintillator arranged in the detection unit and adjacent to the scintillator. A second collimator having a slit on the front surface of each of the scintillators on which X-rays are incident, and having a slit through which X-rays from an X-ray focus can be incident. Is located.

Further, preferably, the slit is a slit having a shape elongated in a direction perpendicular to a direction in which the measurement object or the X-ray tube and the detection unit are rotated.

More preferably, the slit is formed so that the depth direction of the slit is oriented in the direction of the X-ray focal point.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
Will be described with reference to.

FIG. 1 shows an X-ray tube 1 and a detector unit 2 in which a plurality of detection elements are arranged in an arc shape so as to face the X-ray tube 1.
Is arranged, the rotatable measurement object 3 is rotated, and the measurement object 3 is irradiated with X-rays and scattered, and is detected by the detector unit 2.

The detection apparatus thus detected is a third-generation X-ray CT detection apparatus for reconstructing a CT image,
The present invention is an improvement of this third-generation X-ray CT detector.

FIG. 2 is a sectional perspective view of the detection unit 2 of the present invention. A plurality of scintillators 5 are arranged at equal intervals on a substrate 8 formed in an arc shape. (Note that various films arranged on the surface of the substrate 8 are composed of conventional third-generation films, and are disclosed in Japanese Patent Laid-Open No. 62-43.
Since it is also described in Japanese Patent No. 585, description thereof will be omitted.

This scintillator 5 is formed as a polycrystal of activated gadolinium sulfate with praseodymium by a hot isostatic pressing method. A first collimator 6a made of lead which is an X-ray absorbing material, or tungsten or molybdenum is formed between these scintillators 5 and another adjacent scintillator 5.

Further, a second collimator 6b is also formed on the front surface of the scintillator 5 on the side where X-rays are incident, so that the depth direction is directed to the X-ray focal point 7. The measurement object 3 or the X-ray tube and the detection unit have a long slit shape in the rotating direction. The slit 4 has a depth d of 5 mm and a length a of 5 to 1
The width is 0 mm and the width b is 0.2 mm. In this embodiment, the first collimator 6a and the second collimator 6b are integrally formed as the collimator 6.

The slit 4 and the scintillator 5 are also provided.
Are arranged in the detector unit 2 at equal intervals on an arc centered on the X-ray focus 7 as shown in FIG. 1 or FIG. 6, so that only the X-ray flux 9 from the X-ray focus 7 is transferred to the scintillator 5. The collimator 6 makes the collimator 6 absorb X-rays from other directions such as scattered X-rays and prevent them from entering the scintillator 5.

As shown in FIG. 7 (a), the X-ray CT detecting device having such a structure has an interval of slits 4 of the collimator 6b that can measure the X-ray flux 9 at one time. Another X-ray flux 10 existing in this interval moves the detector unit 2 from the position shown in FIG. 7 (a) to the position shown in FIG. 7 (b).
The X-ray that moves slightly around the X-ray focal point 7 and is adjacent to the X-ray bundle 9
The line bundle 10 is measured, and the measurement is performed by repeating this up to the position shown in FIG.

In the present invention, the first collimator 6a and the second collimator 6a
Although the collimator 6b is integrated, the collimator 6b may be divided and processed as shown in FIG.

[0016]

As described above, according to the present invention, since the X-ray is focused by the slit of the collimator, (1) it is not necessary to forcibly reduce the size of the scintillator, and the conventional processing technique can be used for processing.

(2) It is easy to adjust the resolution by shifting the collimator having the slit or modifying the processing.

(3) The resolution can be improved at low cost.

It has the effect of

[Brief description of drawings]

FIG. 1 is a configuration diagram of a detection device for X-ray CT.

FIG. 2 is a sectional perspective view of a detection unit.

FIG. 3 is a plan view of a detection unit.

FIG. 4 is a sectional view of a detection unit.

FIG. 5 is a sectional view of a detection unit of another embodiment.

FIG. 6 is an explanatory diagram showing a relationship between an X-ray focus and a slit of a detection unit.

7A is an explanatory diagram showing a relationship between an X-ray flux and a slit of a detection unit, and FIG. 7B is an explanatory diagram showing a relationship between an X-ray flux after the detection unit is rotated and a slit of the detection unit. , (C) X after the detection unit has rotated again
Explanatory drawing showing the relationship between a wire bundle and the slit of a detection unit.

FIG. 8 is a sectional view of a conventional X-ray CT detector.

[Explanation of symbols]

 1 X-ray tube, 2 detection unit, 3 measurement object, 4 slit, 5 scintillator, 6 collimator, 6a 1st collimator, 6b 2nd collimator, 7 X-ray focus.

Claims (1)

Claim: What is claimed is: 1. An X-ray tube, a detection unit composed of a plurality of detection elements opposed to the X-ray tube, and a measurement object disposed between the X-ray tube and the detection unit. X for rotating the measurement object or the X-ray tube and the detection unit
In the detection apparatus for line CT, a first collimator is arranged between a scintillator arranged in the detection unit and another scintillator adjacent to the scintillator, and the X-ray incident side of each scintillator. A second collimator having a slit through which X-rays from an X-ray focal point can be arranged on the front surface of the X-ray CT detector. 2. The slit is the measurement object or
The X-ray CT detector according to claim 1, wherein the slit is a slit that is long in a direction perpendicular to a direction in which the X-ray tube and the detection unit are rotated. 3. The detection device for X-ray CT according to claim 1, wherein the slit is formed so that a depth direction of the slit is directed to a direction of an X-ray focal point.