JPH06214033A - Scintillation camera - Google Patents

Abstract

PURPOSE:To make the structure of a detector as thin as possible and improve the coupling method for photoelectric multiplier tubes to realize the stabilization in performance of the detector; improve the structure of the flange of a scintillator to ensure the safety at regulation; and provide a small-sized and lightweight detector for scintillation camera excellent in stability and safety CONSTITUTION:A photoelectric multiplier tube 4 is adhered onto a light guide 2 through an acrylic adhesive having high light permeability. A socket part 7 is constituted as covering the photoelectric multiplier tube 4, and its lower edge part is formed into a collar. A cushion 6 taking the role of mechanical cushion is set on the collar part, and an optical shield plate 5 is laid between the collar parts of the adjacent photoelectric multiplier tubes to shield the light from the outside. A base plate 10 is put on the optical shield 5. The base plate 10 and a connector 9 accompanied thereby are housed in the recessed part formed between the photoelectric multiplier tube 4 and the adjacent photoelectric multiplier tube.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scintillation camera, and more particularly to a detector for a scintillation camera.

[0002]

2. Description of the Related Art FIG. 6 shows the structure of the entire detector of a conventional scintillation camera, and FIG. 7 is an enlarged view of that portion (one photomultiplier tube and its peripheral portion in FIG. 6).
Is an example of the holding plate of the photomultiplier tube of FIG.

As shown in FIG. 6, the scintillation camera is optically coupled (optically coupled) on a light guide 62 of a scintillator 61, and a plurality of photomultiplier tubes 64, ..., 64 arranged two-dimensionally. , A photomultiplier tube 64, ..., A bleeder circuit (bleede) provided on the 64
r circuit) 65, ..., 65, bleeder circuit 65 ,.
., 66 for storing positioning sockets,
.., 66, socket portion 66 .., 66, and cable 68
67, 67, photomultiplier tube 64,
.., 64 holding plate 69, photomultiplier tube 64, ..., 6
4 and the spring 70-70 provided between the holding plate 69,
, 70-70, and the bleeder circuit 5 of the photomultiplier tube 4 had a variable resistor 71 as shown in FIG.

Further, the outer portion of the detector is composed of the flange 73 of the scintillator 1, a sot 75 having a light shield 74, and an upper cover (upper flange) 76.
As shown in, the bleeder circuit 5 of the photomultiplier tube 4 has a variable resistor 71, and the upper cover 76 is covered with a lead plate 77.

Further, as shown in FIG. 8, a circular cutout 79 having the same size as the diameter of the socket portion 66 is formed in the holding plate 69.
, Two-dimensionally arranged photomultiplier tubes 64, ..., 6
No. 4 is provided, and photomultiplier tubes 64, ..., 64 optically coupled with a soft material such as silicon grease 72 are provided with springs 70-70 ,.
The photomultiplier tubes 64, ..., 64 are stabilized by pressing vertically from above through -70. In addition, the holding plate 6
A rubber plate 78 for preventing light leakage is provided on the surface 9.

Further, the output from the photomultiplier tube is transmitted through the connectors 67, ..., 67 to the photomultiplier tubes 64 ,.
It consists of a cable assembly that puts together the output of.

[0007]

In the detector of the conventional scintillation camera described above, the coupling of the photomultiplier tube 64 to the light guide 62 is made of silicon grease 72.
Since it was done with a soft material such as
A positioning socket portion 66 having an excellent positioning accuracy for preventing positional deviation, a spring 70-70 for pressing and fixing the photomultiplier tube 64 to the light guide 62, and a pressing member for pressing the photomultiplier tube 64. The holding plate 69 of No. 1 was required.

Further, in the detector of the conventional scintillation camera, the output signal from the photomultiplier tube 64 is integrated by the electrostatic capacity of the cable to the external preamplifier, so that the cable 68 of a certain length (for example, 2 meters) is required. This was one of the reasons that the amount (volume) of the cable was larger than that of the entire detector and the flange of the outer shell was large.

Further, in order to adjust the sensitivity of the detector of the scintillation camera, a photomultiplier tube 64 as shown in FIG. 7 is used.
It is necessary to adjust the variable resistor 71 in the bleeder circuit 65 at the upper part of the above, but conventionally, it is necessary to remove the upper cover 76 covered with the lead plate 77 each time the adjustment is performed. The plate 78 is necessary, and when the variable resistor 71 is to be adjusted, there is a risk of contacting the high voltage bleeder circuit 65.

As described above, in the detector of the conventional scintillation camera, the thickness of the detector is large because the constituent elements are many and bulky, and accordingly, the weight of lead that shields the periphery of the detector from γ rays is heavy. Due to this, there is a problem that the structure itself that supports the detector becomes large and it is difficult to reduce the overall size and weight, and there is a risk of touching the high-voltage bleeder circuit during adjustment. There was a drawback.

The present invention has been made in order to solve the above problems and drawbacks, and aims to make the structure of the detector as thin as possible and to improve the detection method by improving the coupling method of the photomultiplier tube. The stability of the scintillator is improved, the structure of the scintillator flange is improved, and the safety during adjustment is ensured. The purpose is to provide a detector.

[0012]

In order to achieve the above object, a scintillation camera according to a first aspect of the present invention is a detection circuit for detecting incident γ-rays and performing predetermined processing to detect position information and energy signals of the incident γ-rays. In the scintillation camera having, the detection circuit has a photomultiplier tube arranged on a light guide provided on the upper surface of the scintillator, and a socket part fitted to the upper part of the photomultiplier tube, It is characterized in that the socket portion has a horizontally extending edge portion formed on the outer peripheral portion of the lower side.

A second invention is the scintillation camera according to the first invention, wherein the detection circuit includes an integrated circuit board including an electrostatic capacitance element for integrating an output signal from the bleeder circuit provided in the socket. An integrated circuit board is arranged between the edge of the socket of the photomultiplier tube and the edge of the socket of the adjacent photomultiplier tube.

Further, a third invention is characterized in that, in the scintillation camera according to the first invention, the detection circuit has a bleeder circuit provided on an upper surface of the socket portion.

In a fourth aspect based on the third aspect, the detection circuit has a cover for covering the circuit, and a hole for adjusting the bleeder circuit corresponding to the position of the bleeder circuit is provided in the cover. It is characterized by

[0016]

In order to achieve the above object, the scintillation camera according to the first invention has a photomultiplier tube fixed on the light guide provided on the upper surface of the scintillator with an adhesive, so that it is protected against mechanical shock. There is no error such as displacement caused by the above, and there is no need for a spring or a holding plate as in the conventional case. Further, since the female socket portion has an edge portion formed in the outer peripheral portion of the lower side and extending in the horizontal direction and is fitted over the photomultiplier tube, the thickness of the detector can be reduced. The configuration around the detector can be downsized.

The second aspect of the invention includes the electrostatic capacitance element for integrating the output signal from the bleeder circuit provided in the socket on the integrated circuit board, so that the edge portion of the socket portion of the photomultiplier tube is Since it can be arranged between the edge portions of the socket portions of the adjacent photomultiplier tubes, the structure of the peripheral portion of the detector can be downsized.

Further, in the third invention, since the bleeder circuit is provided on the upper surface of the socket portion, the distance between the upper cover of the scintillator camera and the variable resistance of the bleeder circuit is shortened.

[0019]

1 shows an embodiment of the scintillation camera of the present invention, FIG. 2 is a view showing the structure of the socket portion of FIG. 1, and FIG. 3 is one photomultiplier tube of FIG. 1 and its periphery. FIG. 4 is an enlarged view of a portion, and FIG. 4 is a configuration example of the light shield of FIG. 1.

In FIG. 1, 1 is a scintillator, 2 is a light guide, 3 is an adhesive, 4 is a photomultiplier tube, 5 is a light shield plate, 6 is a cushion, 7 is a socket part, 8 is a bleeder circuit, and 9 is. Connector, 10 is an integrated circuit board, 11 is a scintillator flange, 12 is a light shield, 13 is a stud, and 14 is an upper flange.

In FIG. 1, the photomultiplier tube 4 is adhered onto the light guide 2 with an acrylic adhesive having a high translucency. As shown in FIG. 2, the socket portion 7 has a structure so as to cover the photomultiplier tube 4, and the lower edge portion 1
8 is formed in a brim shape. A cushion 6 which serves as a mechanical buffer is installed on the collar-shaped portion 18, and the collar-shaped portions 18 of adjacent photomultiplier tubes are provided as shown in FIG.
The light shield plate 5 is bridged between and to block light from the outside. Further, the substrate 10 is placed on the light shield 5. The substrate 10 and the connector 9 associated therewith can be housed in the valley (recess) formed between the photomultiplier tube 4 and the adjacent photomultiplier tube.

The socket section 7 covers the upper surface of the photomultiplier tube 4, and the bleeder circuit 8 is installed on the socket section 7 as close to the photomultiplier tube 4 as possible. The bleeder circuit 8 uses surface mount components (chip resistors, capacitors, etc.) as much as possible, and these surface mount components are used for the photomultiplier tube 4
It is mounted on the surface on the other side, and the surface on the opposite side is insulation coated.

The substrate 10 is a conventional cable (of a certain length).
Instead of the length, an element (for example, a capacitor) that integrates the output signals of the photomultiplier tubes 4, ..., 4 by electrostatic capacitance is included, and the output is transmitted to an external preamplifier (not shown). However, due to the structure of the socket portion 7 as described above, the substrate 10 is installed below the upper surface of the photomultiplier tube 4, and the photomultiplier tube including the connector 9 with the substrate 10 is included. 4 can be configured to be below the upper surface.

Further, instead of the conventional integration by the electrostatic capacity of the (fixed length) of the cable, the integration is performed by the electrostatic capacity of the capacitor of the integrated circuit, so that the output signal is stabilized. Then, the substrate 10 integrates the outputs of the photomultiplier tubes 4 as shown in FIG. 3, and transmits the integrated output to the preamplifier via the connector 9.

As described above, due to the structure which does not require a spring unlike the conventional detector, the position of the flange 14 is at a level slightly above the bleeder circuit from the height of the photomultiplier tube 4 as shown in FIGS. It is possible to realize a very thin detector (it is at least 80 mm thinner than the thickness of a conventional detector) because it can be lowered to a height and does not require a place for accommodating a cable of a certain length (for example, 2 m). it can).

This means that the height of lead that shields the periphery of the detector can be reduced by about 80 mm, and the weight of the detector as a whole can be reduced by realizing a thin structure. Therefore, the structure of the support portion of the detector can be reduced. Can be simplified and downsized.

The flange 11 is made of an acrylic adhesive 3 so that the photomultiplier tube 4 is stabilized by pressing the photomultiplier tube 4 downward with a spring and a pressing plate as in the conventional detector. It is only necessary to have a structure for supporting the weight of the double tube 4 and the light guide 2 and the scintillator 1, and the flange itself can be thinned.

For this reason, not only the detector can be made thin, but also the detector can be made compact. Accordingly, in particular, the shield cut can be more easily performed during head SPECT (Single photon emission CT) scanning. .

Further, since the cable is used as a substrate, the distance between the photomultiplier tube 4 and the upper cover 14 is shortened. As shown in FIG. 5, a hole 15 for adjustment is opened in the upper cover 14 and the variable resistor 52 is provided. Since the variable resistor can be adjusted by the adjusting device 50 through the adjusting hole by deciding the position of the adjusting portion 51, the light leakage prevention measure at the time of adjustment becomes unnecessary, and the possibility of electric shock due to high voltage is also possible. Disappear.

As a modification of the above, the photomultiplier tube 4 is used.
The light guide 2 and the light guide 2 are made of soft silicone glass which is conventionally used instead of the acrylic adhesive 3, and a spring is used instead of the cushion 6 as in the structure of the above-described embodiment, or a portion formed into a substrate is made by a conventional method. It can also consist of a cable. Further, the bleeder circuit may have the same structure as the conventional one.

Although one embodiment of the present invention has been described above, it is needless to say that the present invention is not limited to the above embodiment and various modifications can be made.

[0032]

As described above, according to the scintillation camera of the present invention, (1) the lower edge portion of the socket portion is formed in a collar shape, and
The socket portion is configured to cover the photomultiplier tube, and the substrate 10 and the connector 9 associated therewith are housed in the valley (recess) formed between the photomultiplier tube 4 and the adjacent photomultiplier tube. Therefore, it is possible to realize a detector in which the thickness of the detector is as thin as possible as a scintillation camera using a photomultiplier tube, and thereby it is possible to simplify and downsize the surrounding structure that supports the detector.

(2) Since the photomultiplier tube is adhered to the light guide with an acrylic adhesive, it is not necessary to stabilize the photomultiplier tube by pressing it with a holding plate and a spring. It is not necessary, which makes it possible to make the scintillator flange thinner. In addition to thinning the detector, it is possible to reduce the size two-dimensionally, and accordingly, the shield cut during the head SPECT scan can be more easily performed. (3) Since the photomultiplier tube is adhered to the light guide with an acrylic adhesive, the coupling agent is mechanically shocked due to the fact that it was conventionally coupled with soft silicone grease or the like. Movement of
A detector with stable performance can be realized.

(4) Conventionally, the signal is transmitted to the preamplifier by the cable assembly, but it is realized on the substrate, so that the structure is simplified and the reliability is improved.

(5) Since the cable is used as a substrate, the distance between the photomultiplier tube and the upper cover is shortened, and the variable resistor can be adjusted through the adjustment hole provided in the upper cover. No leak prevention measures are required, and there is no possibility of electric shock due to high voltage.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a scintillation camera of the present invention.

FIG. 2 is a diagram showing a structure of a socket portion.

FIG. 3 is an enlarged view of a photomultiplier tube and its peripheral portion.

FIG. 4 is a configuration example of the light shield of FIG.

FIG. 5 is an example of a detector in which an adjustment hole is opened in an upper cover.

FIG. 6 is a diagram showing a structure of an entire conventional scintillation camera.

FIG. 7 is an enlarged view of a portion of FIG. 6 (one photomultiplier tube and its peripheral portion).

8 is an example of a holding plate of the photomultiplier tube of FIG.

[Explanation of symbols]

 1 scintillator 2 light guide 3 adhesive 4 photomultiplier tube 7 female socket 8 bleeder circuit 10 integrated circuit board 18 edge

Claims (4)

[Claims] 1. An incident γ ray is captured and a predetermined process is performed to make the incident γ ray.
In a scintillation camera having a detection circuit for detecting line position information and energy signals, the detection circuit comprises a photomultiplier tube arranged on a light guide provided on an upper surface of a scintillator, and a photomultiplier tube. A scintillation camera, comprising: a socket part that fits on an upper part, and the socket part has an edge part that is formed in an outer peripheral part of a lower side and extends in a horizontal direction. 2. The detection circuit has an integrated circuit board including an electrostatic capacitance element for integrating an output signal from a bleeder circuit provided in the socket, and the edge of the socket portion of the photomultiplier tube. 2. The scintillation camera according to claim 1, wherein the integrated circuit board is disposed between the above-mentioned section and the edge of the socket section of another photomultiplier tube adjacent thereto. 3. The scintillation camera according to claim 1, wherein the detection circuit has a bleeder circuit provided on an upper surface of the socket portion. 4. The detection circuit has a cover for covering the circuit, and the cover is provided with a hole for adjusting a bleeder circuit corresponding to the position of the bleeder circuit. Scintillation camera.