KR101088057B1 - Detector modules for positron emission tomography and the positron emission tomography using the same - Google Patents

Abstract

PURPOSE: Detector modules for positron emission tomography and a positron emission tomography using the same are provided to prevent the external loss of the detecting ring of a gamma-ray by forming a detection module. CONSTITUTION: In detector modules for positron emission tomography and a positron emission tomography using the same, a flash layer includes a plurality of flash body. A plurality of stick flash bodies are arranged in pixel type array. A pair of light diffusing layers are respectively connected to both ends of the flash layer. A pair of light diffusing layers diffuses a flashing light signal. A pair of photo sensor arrays(130) converts the flashing light signal into the electric signal. A pair of detection circuits detects the reaction site of the gamma-ray within the flash layer.

Description

Detector modules for positron emission tomography (PET) and positron emission tomography using the same {Detector modules for positron emission tomography and the positron emission tomography using the same}

The present invention relates to a detector module for a positron emission tomography device and a positron emission tomography device using the same. In the dental detector module, a plurality of rod-shaped scintillators constituting the scintillating layer are arranged in parallel with the axial direction of the detection ring, and arranged in a trapezoidal pixel array to form a trapezoidal rectangular parallelepiped detector module. When the ring is formed, the gap between the detector modules is minimized to prevent the gamma rays from being lost to the outside of the detection ring, thereby improving the detection effect of the gamma rays and receiving the gamma rays directly to the side of the scintillator in the longitudinal direction. High resolution image by uniformizing the LOR (Line Of Response) width of gamma rays passing through the scintillator Relates to a positron emission tomography filming reformation detector module, and positron emission tomography apparatus using the same can be obtained.

In general, positron emission tomography (PET) detects a pair of gamma rays generated when a positron of radioactive material injected into a human body collides with a neighboring electron, and detects a gamma ray inside the body through a detection position of the gamma ray. A tomography apparatus for acquiring 3D tomography images.

The positron emission tomography apparatus as described above is largely divided into a detection means and an imaging device. In this case, a plurality of detector modules are radially arranged to form a detection ring, which is radiated from the body. Gamma rays are detected through multiple detector modules.

1 is a view showing a conventional detector module for a positron emission tomography apparatus and a detection ring using the same.

As shown in FIGS. 1A and 1B, the detector module 10 of the conventional positron emission tomography apparatus includes a plurality of scintillators 11 that receive gamma rays on the axis of the detection ring 20. The optical sensor array 12 for detecting the flash signal and the detection circuit unit 13 for detecting the electrical signal of the flash signal are connected to the ends of the plurality of flash bodies 11.

In the case of configuring the detection ring 20 using the conventional detector module 10 as described above, as shown in the drawing, a blank space 14 is formed between the detector modules 10 so that gamma rays emitted from the body are By being separated out of the detection ring 20, there is a problem that the sensitivity (sensitivity) to the gamma ray detection is reduced due to such gamma ray loss.

On the other hand, the detector module 10 is usually produced by modularizing the same size irrespective of the diameter of the detection ring 20, the detection ring 20 composed of such detector modules 10 is the diameter size It is formed differently depending on the shooting target.

That is, when the photographing target is a relatively large object such as the chest of the human body, the diameter of the detection ring 20 is relatively large, and on the contrary, when the photographing target is a relatively small object such as a skull or a small animal of the human body, the detection is relatively large. The diameter of the ring 20 is formed small.

In this case, when the detection ring 20 having a small diameter is formed by using the detector module 10 manufactured with the same size as described above, the detection ring 20 having a large diameter composed of the detector modules 10 having the same size is formed. Inevitably, there is a problem that the relative ratio of the empty space is increased to decrease the detection efficiency such as sensitivity and spatial resolution.

In addition, the conventional detector module 10 as described above has a parallax error in which the spatial resolution deteriorates as the radioisotope moves away from the center, that is, the radioisotope has a gamma-ray imaging area (FOV). At the edge of the view), the gamma ray enters the cross section of the scintillator 11 and passes along the length of the scintillator 11 so that the width of the LOR is increased, thereby reducing the resolution of the image.

In addition, in the case of forming the detection ring 20 having a small size as described above, such a parallax error is further increased, which makes it difficult to obtain a clear image.

As a detector module 10 technology for reducing the width of the LOR developed to solve this problem, two or more scintillators 11 having different attenuation coefficients, such as Lutium Oxyorthosilicate (LSO) and Bismuth Germanate Oxide (BGO), may be used. In the detector module 10, a technique for distinguishing the scintillator 11 reacted with gamma rays by detecting different scintillation signals, using one kind of scintillator 11, and an optical sensor at both ends of the scintillator 11 Each array 12 includes a technique for comparing the amount of light detected by each of the photosensor arrays 12 and one kind of scintillator 11, and the two layers of scintillators 11 are positioned at a predetermined offset. The technique of finding the reaction position of the scintillator 11, etc. are mentioned.

However, these detector modules 10 also have some limitations in reducing the width of the LOR, and when combining these detector modules 10 to form the detection ring 20, there is still a gap between each detector module 10. There is a problem in that a blank space from which the gamma rays are separated to the outside of the detector ring 20 is formed, thereby reducing the detection efficiency of the gamma rays.

The present invention is to solve the above problems according to the prior art. That is, an object of the present invention is to arrange a plurality of bar-shaped scintillator in parallel with the axial direction of the detection ring, arranged in a trapezoidal pixel array to configure the detector module, when forming the detection ring, a plurality of detector modules without gap It is to improve the detection efficiency of gamma rays by preventing the gamma rays emitted from the body due to tight coupling to be lost to the outside of the detection ring.

In addition, a large number of detector modules can be closely coupled regardless of the size of the detection ring, so that the gamma ray detection efficiency is sufficient even in a small diameter proton emission tomography device such as a brain measurement and a small animal proton emission tomography device. Can be secured.

In addition, the object of the present invention is to obtain a high resolution image by directly injecting gamma rays to the side surface in the longitudinal direction of the scintillator to uniformize the LOR (Line Of Response) width of the gamma rays passing through the scintillators.

The present invention as a technical concept for achieving the above object is a detector module for a positron emission tomography apparatus which is arranged radially in a plurality and forms an annular detection ring to detect gamma rays, parallel to the axial direction of the detection ring. A plurality of arranged bar scintillators are arranged in an array of pixel type, wherein the plurality of bar scintillators are arranged in a radial direction cross section of the detection ring to form a trapezoidal shape. Scintillation layer; A pair of light diffusion layers respectively connected to both ends of the scintillation layer to diffuse scintillation signals transmitted from the scintillators constituting the scintillation layer; A pair of optical sensor arrays connected to the pair of light diffusing layers, respectively, for converting a flash signal transmitted from the light diffusing layer into an electrical signal; And a pair of detection circuits connected to the pair of optical sensor arrays, respectively, for comparing and analyzing an electrical signal transmitted from the optical sensor array through a preset detection algorithm to detect a reaction position of gamma rays in the scintillation layer. It is configured to include, characterized in that the gamma rays emitted from the imaging area is configured to receive through the side portion of the plurality of rod-shaped scintillator arranged in parallel with the axial direction of the detection ring.

The detector module for a positron emission tomography apparatus according to the present invention is arranged in parallel with the axial direction of the detection ring, but arranged in a trapezoidal pixel array to form a trapezoidal rectangular parallelepiped detector module to form a detection ring, In this case, the plurality of detector modules are tightly coupled, thereby minimizing the empty space between the detector modules, thereby preventing the loss of gamma rays, thereby increasing the detection efficiency of the gamma rays.

In addition, the gamma ray is incident directly to the side surface in the longitudinal direction of the scintillator, and the LOR (Line Of Response) width of the gamma ray passing through the scintillator is uniform, thereby obtaining a high resolution image.

In addition, since the optical sensor array having an optical amplification function is provided at both ends of the plurality of scintillators, the detection circuit unit can be positioned outside the detection ring, thereby making it possible to more robustly manufacture the detection ring.

In addition, a large number of detector modules can be closely coupled regardless of the size of the detection ring, so that the detection efficiency of gamma rays can be improved even in small diameter proton emission tomography devices such as brain measurement and small animal proton emission tomography devices. At the same time, it is effective to obtain a high resolution image.

1 is a view showing a conventional detector module for a positron emission tomography device and a detection ring using the same.
2 is a view showing a detection ring using a detector module for a positron emission tomography apparatus according to a first embodiment of the present invention.
3 is a view showing the configuration of a detector module for a positron emission tomography apparatus according to a first embodiment of the present invention.
4 is a view showing the configuration of a detector module for a positron emission tomography apparatus according to a second embodiment of the present invention.
5 is a view showing the results of experiments detected by simulating the light emission phenomenon in specific scintillators using the detector module according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a view showing a detection ring using a detector module for a positron emission tomography apparatus according to a first embodiment of the present invention, Figure 2 (a) is a perspective view of the detection ring according to the present invention, Figure 2 (b) is a figure It is sectional drawing which cut | disconnected the detection ring shown to 2 (a) along the AA 'line.

As shown in Figure 2 (a) and 2 (b), the detection ring 200 using the detector module 100 for the positron emission tomography apparatus according to the present invention, each detector module 100 is the shape of a trapezoidal rectangular parallelepiped It is composed of a close contact with each other through each side.

Accordingly, the gap between the detector modules 100 is minimized to prevent the gamma rays from escaping to the outside of the detection ring, thereby reducing the loss of the gamma rays, thereby increasing the detection efficiency of the gamma rays.

In addition, the detector module 100 as described above, even when forming a small-diameter detection ring 200 for detecting a small object such as a human brain or a small animal, the detection ring 200 Regardless of the fabrication size of the, it can be coupled as close as possible, minimizing the space between each detector module 100 can detect the gamma rays without deterioration of sensitivity.

In this case, since the plurality of rod-shaped scintillators 111 constituting the scintillation layer 110 are arranged in parallel with the axial direction of the detection ring 200, the detector module 100 of the scintillator 111 through which the gamma ray passes. The cross-sectional area is uniformed to obtain a high resolution image.

In other words, since the detector module 100 according to the present invention receives the emitted gamma rays through the side surface in the longitudinal direction of the scintillator 111, as shown in FIG. 2 (b), the imaging area of the detection ring 200 ( Even if the radioisotope is at the edge of the photographing area in the field of view (FOV), the emitted gamma ray is incident directly through the side surface of the scintillator 111, thereby uniformizing the width of the LOR (Line Of Response). It can be formed to improve the resolution of the image.

On the other hand, in the detector module 100 as described above, since the gamma rays are incident directly to the side surface in the longitudinal direction of the scintillator 111, the plurality of scintillators 111 are used to detect the incident position of the gamma rays incident on the scintillator 111. The optical sensor array 130 is provided at both ends of each, and the reaction position of the gamma ray with respect to the scintillator 111 is detected by comparing and analyzing each scintillation signal detected by each optical sensor array 130 through a detection circuit unit.

At this time, the specific configuration of such a detector module 100 will be described in detail with reference to FIG.

3 is a view showing the configuration of the detector module 100 for a positron emission tomography apparatus according to the first embodiment of the present invention.

As shown in FIG. 3, the detector module 100 for a positron emission tomography apparatus according to the first embodiment of the present invention includes a scintillation layer 110, a light diffusion layer 120, an optical sensor array 130, and a detection circuit unit ( 140).

Scintillation layer 110 is composed of a plurality of rod-shaped scintillator 111, the plurality of rod-shaped scintillator 111 is arranged vertically parallel to the axial direction of the detection ring, arranged in a trapezoidal pixel array, The gamma rays emitted from the light are incident to generate a flash signal.

At this time, the reflector 115 is formed on the circumferential surface of each of the scintillators 111 so that the flash generated from one scintillator 111 does not spread to the other scintillator 111, and the scintillator 111 is NaI, LSO (Lutetium). It may be composed of a flash crystal such as Oxyorthosilicate (BGO), Bismuth Germanate Oxide (BGO), and Lutepium-Yttrium Aluminate-Perovskite (LuAP).

The light diffusing layer 120 is connected to both ends of the scintillation layer 110 and serves to diffuse each scintillation signal emitted from both ends of the plurality of scintillators 111.

In this case, the light diffusion layer 120 may be made of quartz, glass, or the like, and may be configured in various forms according to the arrangement of the scintillator 111.

The optical sensor array 130 is composed of a semiconductor type optical sensor having an optical amplification function, such as a silicon photoelectron multiplier or a silicon photoelectron multiplier that amplifies the photoelectron, and is connected to the light diffusion layer 120.

The optical sensor array 130 is positioned at both ends of the scintillation layer 110 to detect the reaction position of the gamma ray incident on the scintillator 111, and is output from both ends of the scintillator 111, so that the light diffusion layer 120 is provided. It serves to convert each of the flash signal spread through the electrical signal.

On the other hand, the photosensor array 130 has a plurality of photosensors 132 are arranged in a pixel shape, wherein a plurality of photosensors 132 pixels are arranged in a trapezoidal shape so as to match one to one with a plurality of scintillator 111 pixels, respectively. do.

That is, when cutting along the line B-B 'shown in the drawing and looking at the optical sensor array 130 from the bottom, a plurality of optical sensors 132 constitute a trapezoidal pixel array on the trapezoid-shaped substrate 131. And a plurality of optical sensors 132 constituting the optical sensor array 130 and a plurality of rod-shaped scintillators 111 constituting the scintillating layer 110. By being configured to match each one to one, it is possible to detect the flash signal generated from each of the scintillator 111 through the corresponding light sensor 132 matched.

In this case, in order to further improve the resolution of the image, the pixel size of the scintillator 111 may be subdivided from the pixel size of the optical sensor 132. In this case, the positioning logic based on the size of the optical signal incident to each optical sensor may be used. High resolution images can be obtained by determining the response position of gamma rays.

The detection circuit unit 140 is connected to each optical sensor array 130 to amplify each electrical signal measured from the optical sensor array 130 through a preamplifier (not shown), and compare the magnitude of each amplified signal. By analyzing it serves to detect the reaction position of gamma rays in the scintillator.

On the other hand, in the present invention, the optical sensor array 130 is composed of a silicon photoelectron multiplier tube or a semiconductor optical sensor having a high signal amplification factor. Since the optical sensor 132 generally has a gain of 10 ⁵ or more, the optical sensor array Even if the preamplifier 130 is separated from the preamplifier 2 m or more, the flash signal can be transmitted to the preamplifier without loss of the signal.

Accordingly, in the detector module 100 according to the present invention, the detection circuit unit 140 is connected to the optical sensor array 130 through a coaxial cable 300 or the like without the need to bring the detection circuit unit 140 close to the optical sensor array 130. It can be located outside, and the structure of a detection ring can be made easier.

4 is a view showing the configuration of a detector module for a positron emission tomography apparatus according to a second embodiment of the present invention.

As shown in FIG. 4, the detector module for a positron emission tomography apparatus according to the second embodiment of the present invention has the same basic configuration as the detector module for a positron emission tomography apparatus according to the first embodiment of the present invention described above. .

However, the flash layer 110 according to the present exemplary embodiment includes a plurality of rod-shaped flash bodies 112, 113, and 114 stacked in three layers arranged in a trapezoidal pixel array. The bar scintillators 112, 113, and 114 arranged in the scintillator layers constituting the scintillator layer are offset from the left and right by an array of the bar scintillators 112, 113, and 114 that constitute the scintillator layers adjacent to each other. The difference is that they are arranged in a form.

Even in this case, reflectors 117 are formed on the side surfaces of the respective scintillators 112, 113, and 114, and as shown in the drawing, when the gamma rays are incident on the specific scintillator 113, the incident gamma rays are The flash is generated in the scintillator 113, and the scintillation is moved along the scintillator 113 to be diffused through the light diffusion layer 120 by way of the adjacent scintillators 112 and 114 to be diffused through the light sensor array 130. Are respectively input as flash signals.

At this time, the light sensor array 130 receives a flash signal having different amounts of light and temporal characteristics from each of the light bodies 112 and 114 adjacent to the specific light body 113, and the light sensor array 130 receives each of the light flashes. The signals are converted into electrical signals, and the detection circuit unit 140 analyzes each of these electrical signals by using a preset detection algorithm to precisely determine the reaction positions of the corresponding scintillator 113 and the scintillator 113 having interacted with gamma rays. Can be measured.

As described above, the detector module according to the present embodiment can more accurately detect a gamma ray response position with respect to the scintillators 112, 113, and 114 by generating, comparing and analyzing a plurality of scintillation signals with respect to one gamma ray. As a result, the detection efficiency of the gamma ray can be increased to obtain more improved spatial resolution.

In addition, when the scintillator layer is formed by stacking three layers as described above, if the scintillator layer is formed of scintillators of different materials having different characteristics for each layer, the reaction position of the gamma ray can be detected more accurately.

FIG. 5 is a view showing an experimental result obtained by simulating the light emission phenomenon of specific scintillators using the detector module according to the present invention. FIG. 5 (a) schematically shows the configuration of the detector module used in this experiment. 5 (b) is a graph showing the results obtained by simulating the light emission phenomenon of specific scintillators through the detector module described with reference to FIG. 5 (a).

As shown in FIG. 5 (a), in the present embodiment, in constructing a detector module for a positron emission tomography apparatus, a 30 mm thick 2.2 mm pixel LSO scintillator, a 1 mm thick light diffusion layer, and two 8 × 4 optical sensor arrays are provided. Configured.

Among the scintillators constituting the detector module using the detector module configured as described above, gamma rays were detected on the scintillators at 3x3, 3x4, 4x1, and 4x2 positions to detect the measured signal, and as shown in the graph shown in FIG. A signal as was detected.

In this case, the X axis of the graph represents a position value at which the flash is generated in the entire length of the scintillator, and the Y axis represents a ratio value comparing each scintillation signal detected by each optical sensor array.

Looking at the graph as described above, as each pixel is a position where the gamma ray is incident on the scintillator, that is, the position where the flash occurs toward the bottom of the scintillator, the flash signal detected by the photosensor array at the bottom becomes larger and larger. On the contrary, as the position where the flash is generated reaches the top of the scintillator, the flash signal detected by the optical sensor array at the bottom becomes smaller.

By using this principle, each optical sensor array detects each of the flash signals output from both ends of the scintillator, and each of the detected flash signals is converted into an electrical signal through the optical sensor array, and the converted electrical signals are detected by the detection circuit unit. In comparison, the image is output as image information through the display device.

As described above, the detector module for a positron emission tomography apparatus according to the present invention constitutes a detector module in which a plurality of scintillators are positioned in the axial direction of the detection ring and stacked in a trapezoidal rectangular parallelepiped form, thereby forming a plurality of detector modules in forming a detection ring. This tight coupling is achieved, thereby minimizing the void space between the detector modules, thereby preventing the loss of gamma rays, thereby increasing the detection efficiency of the gamma rays.

In addition, the gamma ray is directly incident on the side surface of the scintillator in the longitudinal direction, and a high resolution image can be obtained by uniformizing the LOR (Line Of Response) width of the gamma ray passing through the scintillator.

In addition, by providing an optical sensor array having an optical amplification function at both ends of the plurality of scintillators, the detection circuit portion can be positioned outside the detection ring, thereby making the detection ring more robust.

In addition, a large number of detector modules can be closely coupled regardless of the size of the detection ring, so that the detection efficiency of gamma rays can be improved even in small diameter proton emission tomography devices such as brain measurement and small animal proton emission tomography devices. At the same time, a high resolution image can be obtained.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is common in the art that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be clear to those who have knowledge of God.

10, 100: detector module 11, 111, 112, 113, 114: scintillation body
12, 130: optical sensor array 13, 140: detection circuit
14: blank space 20, 200: detection ring
110: scintillation layer 120: light diffusion layer
131: substrate 132: optical sensor
115, 117: reflector

Claims (11)

A detector module for a positron emission tomography apparatus, wherein a plurality of radially arranged beams are formed to form an annular detection ring to detect gamma rays.
A plurality of bar scintillators arranged in parallel with the axial direction of the detection ring is arranged in an array of pixel types, wherein the pixel array in which the plurality of bar scintillators are arranged has a radial cross section of the detection ring. A glare layer arranged to form a trapezoidal shape;
A pair of light diffusion layers respectively connected to both ends of the scintillation layer to diffuse scintillation signals transmitted from the scintillators constituting the scintillation layer;
A pair of optical sensor arrays connected to the pair of light diffusing layers, respectively, for converting a flash signal transmitted from the light diffusing layer into an electrical signal; And
A pair of detection circuits connected to the pair of optical sensor arrays, respectively, for comparing and analyzing an electrical signal transmitted from the optical sensor array through a preset detection algorithm to detect a reaction position of gamma rays in the scintillation layer; Consists of including,
And a gamma ray emitted from a photographing area is incident through side surfaces of a plurality of rod-shaped scintillators arranged in parallel with the axial direction of the detection ring.
The method of claim 1,
A detector module for a positron emission tomography apparatus, characterized in that a reflector is formed around each of the rod-shaped scintillators constituting the pixel array.
Claim 3 was abandoned when the setup registration fee was paid. The method of claim 1,
The optical sensor array is a detector module for a positron emission tomography device, characterized in that consisting of a silicon photomultiplier tube or a semiconductor optical sensor.
Claim 4 was abandoned when the registration fee was paid. The method of claim 1,
And the pair of detection circuit units are connected to the pair of optical sensor arrays via cables, respectively, and are provided at positions spaced apart from the detection ring by a predetermined distance.
Claim 5 was abandoned upon payment of a set-up fee. The method of claim 1,
The scintillator is any one of NaI, LUT (Lutetium Oxyorthosilicate), BGO (Bismuth Germanate Oxide) or LuYAP (Lutetium-Yttrium Aluminate-Perovskite) detector module for positron emission tomography apparatus.
Claim 6 was abandoned when the registration fee was paid. The method of claim 1,
The light diffusing layer is a detector module for a positron emission tomography device, characterized in that consisting of quartz or glass.
The method of claim 1,
The optical sensor array is configured in the form of a chip on board (COB) mounted on the trapezoidal substrate such that a plurality of optical sensors constitute a trapezoidal pixel array, and the plurality of optical sensors constituting the optical sensor array are the flashes. A detector module for a positron emission tomography apparatus, characterized in that configured to match one-to-one with a plurality of rod-shaped scintillators constituting a layer.
A detector module for a positron emission tomography apparatus, wherein a plurality of radially arranged beams are formed to form an annular detection ring to detect gamma rays.
A plurality of rod-shaped scintillators arranged in parallel with the axial direction of the detection ring and stacked in three layers in the longitudinal direction are arranged in an array of pixel types, and the pixel array in which the plurality of rod-shaped scintillators are arranged A glare layer configured to be arranged such that a radial cross section of the detection ring forms a trapezoidal shape;
A pair of light diffusion layers respectively connected to both ends of the scintillation layer to diffuse scintillation signals transmitted from the scintillators constituting the scintillation layer;
A pair of optical sensor arrays connected to the pair of light diffusing layers, respectively, for converting a flash signal transmitted from the light diffusing layer into an electrical signal; And
A pair of detection circuits connected to the pair of optical sensor arrays, respectively, for comparing and analyzing an electrical signal transmitted from the optical sensor array through a preset detection algorithm to detect a reaction position of gamma rays in the scintillation layer; Consists of including,
And a gamma ray emitted from a photographing area is incident through side surfaces of a plurality of rod-shaped scintillators arranged in parallel with the axial direction of the detection ring.
The method of claim 8,
The bar scintillators stacked and arranged in three layers in the length direction on each scintillator layer constituting the scintillating layer are arranged in the form of an array of bar scintillators adjacent to each other in the length direction and offset by a predetermined interval from each side. Detector module for positron emission tomography apparatus, characterized in that the.
The method of claim 8,
The scintillation layer laminated in three layers each in the longitudinal direction is a detector module for a positron emission tomography apparatus, characterized in that composed of scintillators of different materials for each layer stacked.
12. A positron emission tomography apparatus comprising an annular detection ring formed by radially arranging said detector modules using a detector module having the configuration of any one of claims 1 to 10.

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