JPH08229029A - Detecting device for x-ray ct device - Google Patents

Abstract

PURPOSE: To finely arrange detector modules into a circular arc shape with the simple work with no interference between them when they are fitted regardless of the deviation in manufacturing and machining accuracy. CONSTITUTION: An oblong hole 9 is bored at the center of a support base 5, i.e., at the center of a detector module, and oblong holes 8, 10 not penetrating the support base 5 are formed at the right and left symmetrical positions of the oblong hole 9. Cylindrical pins 11, 12 to be coupled with the oblong holes 8, 10 are formed on a fitting plate 1. When the oblong holes 8, 10 of the support base 5 are coupled with the pins 11, 12, the detector module is faced to an X-ray tube, and the oblong holes 8, 9, 10 have strokes in the incidence direction of X-rays from an X-ray tube in the direction of their major axes so that the detector module can be moved in this direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray detection apparatus in which a large number of block-shaped detector modules for detecting X-rays are arranged in an arc in an X-ray CT apparatus.

[0002]

2. Description of the Related Art In an X-ray CT apparatus, for example, as shown in FIG. 4, X-rays emitted from an X-ray tube 31 pass through an object 32 and are then arranged in an arc shape through a collimator 33 for removing scattered rays. Are detected by the detector array 34.

As shown in FIG. 5A, the collimator 33 comprises support plates 35 and 36 and a shield plate 38 which constitutes a collimator. The shield plate 38 is inserted and fixed between the support plates 35 and 36. There is.

On the other hand, the detector array 34 is composed of a photodiode array 40, a shielding material 41, and a scintillator element 42 as shown in FIG. 5B, and this detector array is fixed on a holding plate 39. There is.

The X-rays that have passed through the spaces partitioned by the shield plate 38 are detected by the detector array.

The detector array on the holding plate 39 is arranged in an arc shape on the back surface of the collimator so that the opening of the scintillator element 42 corresponds to the opening of the shield plate 38 as shown in FIG.

The holding plate and the detector array are designed so that the gap between them is as small as possible, and are fixed to the support plates 35 and 36 of the collimator.

[0008]

By the way, as described above, the detector arrays are arranged in a polygonal shape so as to approach an arc shape, and the gap between the detector arrays is made as small as possible. Is designed.

However, the manufacturing precision of the detector array itself,
When arranging the detector arrays in an arc shape, the adjacent detector arrays collide with each other and the detector arrays are mounted at the specified positions due to errors that occur due to the processing accuracy and mechanical accuracy of the holding plate to which the detector arrays are attached. Since there is a possibility that it will not be possible to do so, designing has been done with these errors in mind. Therefore, the processing accuracy becomes important, and the gap between the detector arrays becomes large, so that the area where X-rays cannot be detected is widened, which causes an artifact.

The present invention was devised to solve the above-mentioned problems. Even if the manufacturing and processing accuracy is incorrect, each detector module (array) interferes with each other when the detector modules (array) are attached. The present invention provides a detection device for an X-ray CT device, which can be arranged in a fine arc shape by a simple operation without performing the above.

[0011]

In order to achieve the above-mentioned object, a detector of an X-ray CT apparatus according to the present invention has a block-shaped detector module consisting of an X-ray detector and a support for the X-ray detector. A plurality of arc-shaped arrangements, and a mounting portion for mounting each detector module in a circular arc on a mounting plate arranged on the side surface of the detector module, and X on the mounting portion.
It is characterized in that a mounting position adjusting mechanism that can move the detector module along the incident direction of the line is provided.

[0012]

A large number of block-shaped detector modules each including an X-ray detector and a support for the X-ray detector are mounted on the mounting plate in an arc shape, but they are adjacent to each other due to an error in processing accuracy or assembly accuracy of the detector modules. If the detector modules interfere with each other and cannot be mounted in place, move the detector module with the error downward along the X-ray incidence direction until it does not collide with the adjacent detector module. By doing so, it is possible to arrange these detector modules so as to maintain the arcuate shape without forming a gap between the detector modules.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 (a) is an overall view of a detector for an X-ray CT apparatus according to the present invention, FIG. 1 (b) is a sectional view taken along line AA, and FIG. 2 is a detail of two adjacent detector module parts. The figure is shown. 1 is a mounting plate, 2 is a collimator, 3 is a scintillator element, 4 is a photodiode array, 5 is a support base,
6 is a shielding plate or a reflector, 8, 9 and 10 are long holes, 11,
12 is a pin, 13 is a fixing screw, and 14 is an X-ray tube.

The scintillator elements 3 convert incident X-rays into light and are arranged in an array so that the shielding plate 6 prevents light from leaking to the adjacent scintillator elements. Here, the scintillator elements 3 arranged in an array, the shield plate 6 formed between these scintillator elements, and the scintillator element 3 are attached to the surface opposite to the X-ray incident direction, and light from the scintillator elements is attached. Together with the photodiode array 4 for converting into an electric signal form an X-ray detection section. Further, the photodiode array 4 of the X-ray detection section and the support base 5 joined to the photodiode array 4 constitute a detector module.

An elongated hole 9 is hollowed out at the center of each support 5, that is, the center of the detector module, and elongated holes 8 and 1 which do not penetrate the support 5 at symmetrical positions of the elongated hole 9.
0 is formed. Further, cylindrical pins 11 and 12 are formed on the mounting plate 1 so as to be fitted into the elongated holes 8 and 10.

When the detector module is mounted on the mounting plate 1, the positions of the pins 11 and 12 are predetermined such that the continuous surface of the X-ray incidence surface of the detector module is centered on the point P of the X-ray tube 14. It is installed so that an arc is drawn with a radius of and the line connecting the center of the detector module and the point P makes an angle of approximately 90 degrees with the scintillator element surface of the detector module.

Therefore, when the elongated holes 8 and 10 of the support base 5 are fitted to the pins 11 and 12, the detector module is oriented in the direction of the X-ray tube, and the detector module can be moved in this direction. In addition, the long axis direction of the long holes 8, 9 and 10 is X.
It has a stroke in the direction of incidence of X-rays from a ray tube.

Further, in order for the fixing screw 13 to fix the support base 5 at a predetermined position of the mounting plate 1, a screw hole is formed in the mounting plate 1 so as to be fitted with the fixing screw 13.

That is, the elongated holes 8, 9, 10 and the pin 11,
12, the fixing screw 13 serves as a mounting portion, and the moving range of the elongated holes 8, 9, 10 in the major axis direction serves as a mounting position adjusting mechanism.

Each of the detector modules is constructed as described above. Normally, if there is no error in the assembly accuracy and the processing accuracy of each detector module, the pins 11 and 12 up to the lowermost portions of the elongated holes 8 and 10 are usually provided. Slide the position, fixing screw 1
If fixed at 3, the X-ray incidence surface of each detector module is continuous without a step and has an arc shape.

However, as shown in FIG. 2, for example, when the scintillator array and the photodiode array are formed at different positions so that their side surfaces do not coincide with each other, the adjacent detector modules of the adjacent detector modules are attempted to be mounted on the mounting plate 1. I can not attach it by hitting the scintillator array,
Move the detector module itself downward (oblong holes 8, 1,
The positions of the pins 11 and 12 at 0 are shifted upward), so that the attachment can be easily performed without forming a gap with the adjacent detector unit.

In this way, if the detector modules are attached one after another, the line connecting the center of the detector module and the point P is approximately 90 degrees with the scintillator element surface of the detector module only by adjusting the vertical direction. While keeping the angle of
Each detector module can be arranged in an arc.

When the detector modules are arranged as described above, the distance from the X-ray tube will change for a specific detector module, but the opening area of the collimator should be smaller than that of the scintillator. In this case, there is no difference in sensitivity between the detector modules.

By the way, the elongated holes 8 to 10 are arranged in the lateral direction (X
When it is formed in the direction perpendicular to the incident direction of the line), the detector module with an error can be adjusted so as not to collide with the adjacent module, but the correct detector module next to the module with an error is also one after another. Since the position must be laterally adjusted so as to be in close contact with, the opening of the collimator does not coincide with the opening of the scintillator element of the accurate detector module, and accurate X-ray detection cannot be performed.

In the above embodiment, the elongated holes 8 and 10 of the support base 5 are fitted into the pins 11 and 12 so that they are densely arranged, so that the detector module may be damaged due to a defective X-ray detector, for example. In the case of replacement, the defective detector module is difficult to pull out due to the influence of the collimator and the adjacent detector module, and the replacement work is difficult. Moreover, if the film is forcibly pulled out, it may damage the scintillator, the photodiode array, or the like.

Therefore, an embodiment of a structure that can easily and safely perform this replacement work will be described below.

In FIG. 3, the same numbers as those used in FIGS. 1 and 2 indicate the same items, and FIG. 3 (b) shows B in FIG. 3 (a).
-B shows a cross section.

In addition to the structure of the long hole, the pin and the fixing screw, the screw hole 21 is formed in the lower portion of the support base 5. In the figure, the screw hole 21 is provided so as to penetrate so as to reach the mounting plate 1, but the screw hole 21 may be formed before reaching the mounting plate 1 so as not to penetrate.

When it is desired to pull out the detector module, the screw 20 that fits into the screw hole 21 is turned to an appropriate position to form a hand-holdable portion as shown in FIG. And pull it out.

On the other hand, a screw hole 21 is formed so as to reach the mounting plate 1, a screw 20 longer than the stroke of the screw hole 21 is rotated and pushed in, and the screw 20 is pressed against the mounting plate 1 and detected by this repulsive force. The vessel module may be removed.

The position of the screw hole 21 is preferably provided in the lower portion of the support base 5 so as not to damage the photodiode array 4 and the scintillator element 3.

Here, the present invention includes the following embodiments.

A screw hole into which a predetermined screw can be inserted from the side opposite to the mounting plate is provided on the support base of the detector module at a substantially right angle to the mounting plate, and a screw is fitted into this screw hole and the screw is gripped. The detection device for an X-ray CT apparatus according to claim 1, wherein the detector module is pulled out or the screw is pressed against a mounting plate and pulled out.

[0035]

As described above, the X-ray CT of the present invention
According to the detection device of the device, since each detector module arranged in an arc has a stroke that can be moved in the X-ray incident direction, the processing and manufacturing precision of each component of this detector module and its assembly. Even if the accuracy is incorrect, when arranging each detector module, it is possible to arrange the detector modules densely without collision with the adjacent detector modules only by adjustment by a simple movement.

[Brief description of drawings]

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

FIG. 2 is an enlarged view of the detection device of the present invention.

FIG. 3 is a modified embodiment of the detection device of the present invention.

FIG. 4 is a diagram showing a schematic configuration of an X-ray CT apparatus.

FIG. 5 is a diagram showing a configuration of a conventional radiation detection unit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryoichi Sawada 1 Nishinokyo Kuwabara-cho, Nakagyo-ku, Kyoto City Stock Company Shimadzu Sanjo Factory

Claims (1)

[Claims] 1. An apparatus comprising a large number of block-shaped detector modules densely arranged in an arc shape, each block-shaped detector module including an X-ray detector and a support for the X-ray detector, wherein a mounting plate disposed on a side surface of the detector module. Detection of an X-ray CT apparatus, characterized in that a mounting portion for mounting each detector module in an arc shape and a mounting position adjusting mechanism capable of moving the detector module along the X-ray incident direction are provided in the mounting portion. apparatus.