JPH1039037A - Radiation detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To readily adapt to design change of a collimator section, to readily execute position alignment of an aperture pitch of the collimator with a detection element of a detector block and to improve a manufacturing efficiency. SOLUTION: A side plate 2 is laid down, a metallic mold 1 is disposed by fitting a pin 1b thereof to a pin hole 5 so as to obtain firm securing. Next, adhesive is coated to a bottom side face of a shield plate 3 which is brought into contact with the side plate 2 when the shield plate 3 that is cut in a predetermined size beforehand is inserted into a groove 1a, then the shield plate 3 is inserted into the groove 1a and is slid thereinto until the bottom to be bonded to the adhesive section 9 of the side plate 2. The above operation is repeated by the number of the grooves 1a. After the shield plates 3 are bonded to the side plate 2, a support plate 4 is covered to an opening section formed on the metallic mold 1 to be bonded thereto. After the bonding is completed, the metallic mold 1 is pulled upward. A detector block is attached to the bottom face of the side plate 2, then it is attached to a device body in an arc shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a radiation detector used for an X-ray CT, an industrial X-ray inspection apparatus, and the like.

[0002]

2. Description of the Related Art For example, an X-ray CT apparatus comprises an X-ray tube 31, a collimator 34 and a radiation detector 35 as shown in FIG.
The fan-shaped X-ray beam 32 emitted from the X-ray tube 31 passes through the subject 33, passes through the collimator 34,
After unnecessary scattered X-rays are removed, the scattered X-rays are detected by a radiation detector 35 in which a number of radiation detection elements are arranged in an array. The radiation detector 35 is a solid-state radiation detector in which a combination of a scintillator that converts radiation into light and a photoelectric conversion element that converts this light into an electric signal is arranged in a one-dimensional array in parallel. The entire radiation detector 35 is formed by arranging 8 to 40 combinations of photoelectric conversion elements into one block, and arranging the detector blocks 36 continuously in a polygonal shape on the circumference.

As shown in FIG. 7, the collimator 34 includes supporting plates 41 and 42 and a shielding plate 45 constituting the collimator. The shielding plate 45 is inserted along a groove 44 provided in the supporting plates 41 and 42. It is fixed.

In the collimator 34, a shielding plate 45 is inserted corresponding to an opening of each detector so that transmitted X-rays can be accurately detected by each detector of the detector block 36. The X-rays that have passed through each space partitioned by the shielding plate 45 are detected by the detector block 36.

[0005] Each detector block is arranged very close to the polygonal side with the X-ray focal point as the center so that there is no leakage in the radiation detection.

On the other hand, the collimators are arranged at equal angles and at equal intervals so that a shielding plate having a high atomic number, such as tungsten or molybdenum, having a high X-ray shielding ability is directed to the focal point of X-rays. I have. That is, when a collimator is manufactured, a groove 44 having a thickness of a shielding plate 45 is formed in two support plates 41 and 42 made of ceramic or the like in accordance with the number of detectors. , 42 facing each other and 1
The collimator is formed by inserting one sheet and one shielding plate 45 and bonding and fixing the same.

Further, a mold is manufactured in advance, a groove for inserting the shielding plate 45 is formed inside the mold, and after inserting the shielding plate 45 into the mold, the support plates 41 and 42 are sandwiched from both sides. In some cases, a collimator is formed by bonding a mold and pulling out a mold.

[0008]

However, since the size of the entire collimator is large, a large-sized device and a metal mold are required, and the thickness and length of the shielding plate and the arrangement pitch of the shielding plate are designed. The change requires a lot of cost and labor, and even if a partial manufacturing defect occurs, the collimator cannot be used as a whole, resulting in a decrease in production efficiency.

Further, it is not easy to align the aperture pitch of the collimator with the detection element of the detector block.

The present invention has been made in order to solve the above-mentioned problems, and can easily cope with a design change of the collimator, and can easily align the aperture pitch of the collimator with the detection element of the detector block. Another object of the present invention is to provide a radiation detector which can increase production efficiency and does not cost much.

[0011]

In order to achieve the above object, a radiation detector according to the present invention comprises a detector in which a plurality of fluorescent elements emitting light in accordance with the amount of incident radiation and a plurality of photodetectors are bonded. In a radiation detector formed by arranging a large number of blocks in an arc shape in a predetermined direction, collimator means for preventing incident scattered radiation between elements of the detector block is incorporated in the detector block and integrated. Features.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described based on Nos.

FIG. 1 shows a manufacturing process of the radiation detector according to the present invention, FIG. 2 shows a side view of the manufacturing process of FIG.
4 shows a front view of the completed view of the detector module, and FIG. 4 shows a side view of the completed view of the detector module.

Reference numeral 1 denotes a mold having a hollow inside, 1a denotes a groove formed in the mold 1, 2 denotes a metal side plate, 3 denotes a material having a large atomic number such as tungsten or molybdenum, and shields radiation. Shield plate, 4 is stainless steel,
An arc-shaped support plate made of aluminum or the like.

The hollow portion of the mold 1 is formed by wire electric discharge machining or the like into a bow shape that forms a part of an arc centered on the focal point P of radiation so as to follow the entire outer shape of the collimator. Grooves 1a are formed on the inner part of the arcuate portion after being hollowed so as to face left and right, and pins 1b are formed on the back surface.

The groove 1a is formed in accordance with the side width of the shielding plate 3 so that the shielding plate 3 can be inserted from above, and is formed in a strip shape at a predetermined pitch corresponding to the number of fluorescent elements such as scintillators. ing.

The support plate 4 is formed in an arc shape so as to form a part of an arc centered on the focal point P of the radiation so as to be accommodated in the hollow portion of the mold 1, and in the hollow portion. It is configured to be slightly smaller than the area.

The side plates 2 are formed in a trapezoidal shape so that when they are arranged side by side and densely arranged, the whole becomes an arc shape, and the screw holes 6 are located at symmetrical positions on the center line of the trapezoid. A pin hole 5 is provided, and the pin hole 5 is
And can be fitted with the pin 1b on the back surface of the. Further, a screw hole 7 and a pin hole 8 are formed on the lower surface of the side plate 2 so that a detector block formed of a fluorescent element and a light detecting element can be attached.

Next, a method for manufacturing the radiation detector will be described.

First, the side plate 2 is placed on the lower side, and the pins 1b of the mold 1 are fitted and arranged in the pin holes 5, so that the positions are not shifted.

Next, an adhesive is applied to a surface of the shielding plate 3 cut into a predetermined size in advance and abutting against the side plate 2 when the shielding plate 3 is inserted into the groove 1a, that is, a lower surface of the plate 3, so that the shielding plate 3 is grooved. 1a and slide it down,
It is bonded to the bonding portion 9 of the side plate 2. This operation is repeated by the number of grooves 1a.

After inserting the shielding plates 3 into all the grooves and adhering them to the side plates 2, the supporting plate 4 is put on the cut-out openings of the mold 1 from above and the upper surface of each of the shielding plates 3 already inserted. And bonding with an adhesive.

In this way, after all the fixing is completed, the mold 1 is pulled out to form a collimator portion.

Next, as shown in FIGS. 3 and 4, a ceramic plate 14 to which a scintillator array 10 as a fluorescent element and a photodiode array 11 as a photodetector are bonded is attached to the lower surface of the side plate 2.

The shielding plate 3 in the collimator portion is formed so as to be arranged at the boundary of each element of the scintillator array 10 and is usually formed at an equal pitch in consideration of productivity. The element may be formed so that the width of the element becomes larger toward both ends than the width of the central portion so as to be able to. Further, the photodiode array 11 can be similarly formed.

Pins are formed in the ceramic plate 14 so as to fit into the pin holes 8 of the side plate 2, and screw holes corresponding to the screw holes 7 are formed. Of the ceramic plate 14
Through the screw hole 7 of the side plate 2 and fixed. At this time, the collimator opening pitch is set to correspond to the detection element.

In order to form the shielding plate 3 corresponding to the boundary between the adjacent scintillator arrays 10,
Only one of the rightmost end and the leftmost end is provided with the shielding plate 3 at the bonding portion 9 of each detector module.

Thus, the detector module is completed.

Next, an example in which a number of radiation detectors of the present invention are arranged in an apparatus will be described with reference to FIG.

The mold 1 is repeatedly used in the manner described above to produce the required number of detector modules, and these detector modules are mounted on the mounting base plate 12 of the apparatus by the radiation focus P.
Are arranged along an arc shape centered at.

The base plate 12 is provided with the pins 13a corresponding to the positions where the detector modules are arranged so that the detector modules are densely arranged in an arc shape. 5, a pin of the base plate 12 is fitted, and a screw is passed through the screw hole 6 to form a screw hole 13 of the base plate 12.
b.

As described above, the detector modules oriented in the focus direction of radiation are densely arranged, and a radiation detector connected in an arc shape is formed.

In the above embodiment, an example in which a mold is used has been described. However, the side plate 2 and the support plate 4 are cut into grooves having the thickness of the shielding plate 3 in correspondence with the number of detectors. With the plates facing each other, insert 1
One, one, and the shielding plate 3 may be inserted and adhered and fixed.

[0034]

As described above, according to the radiation detector of the present invention, the collimator is partially divided in accordance with the detector block without integrating the collimator, and is divided into each detector block. Since the collimator and the collimator are integrally modularized, it is easy to manufacture the divided collimator portion, and even if the design is changed, the change operation can be minimized.

Further, the detector and the collimator can be evaluated as a module by inspection, and the inspection efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a manufacturing process of a radiation detector according to one embodiment of the present invention.

FIG. 2 is a diagram showing a state from the side of FIG. 1;

FIG. 3 is a view showing the entire front of the detector module.

FIG. 4 is a diagram showing an entire side surface of the detector module.

FIG. 5 is a front view when the detector module is attached to the apparatus main body.

FIG. 6 is a diagram showing a schematic configuration of an X-ray CT apparatus.

FIG. 7 is a diagram showing a configuration of a collimator of a conventional radiation detector.

Claims (1)

[Claims] 1. A radiation detector formed by arranging a large number of detector blocks in which a plurality of fluorescent elements emitting light in accordance with an incident radiation dose and a plurality of light detecting elements are bonded in a predetermined direction in an arc shape. A radiation detector, wherein collimator means for preventing incident scattered radiation between the elements of the detector block are integrated into the detector block.