CN115201885A - A Gamma Camera Detector with Improved Spatial Resolution - Google Patents

Abstract

A gamma camera detector with improved spatial resolution comprising a collimator layer (211), a scintillator layer (212), a light guide layer (213), a PMT array layer (214); and a circle of extension light guide is arranged on the outer side of the scintillation crystal in a clinging manner, and the extension light guide is attached to the side surface of the scintillation crystal. A method for assembling a gamma camera detector comprises the following steps: (1) fixing the filling member and the extension light guide in sequence; (2) Placing and fixing a PMT array layer at the top in a detector shell; (3) The light guide layer, the scintillation crystal layer and the collimator layer are sequentially installed, the PMT array layer, the light guide layer, the scintillation crystal layer and the collimator layer are sequentially and closely attached and fixed, and the side faces of the extension light guide and the scintillation crystal are coupled through optical cement or silicon oil and attached together.

Description

A Gamma Camera Detector with Improved Spatial Resolution

technical field

The present invention relates to the technical field of gamma camera technology improvement used in SPECT detection, in particular to a gamma camera detector with improved spatial resolution.

Background technique

SPECT machine is a nuclear medicine imaging equipment developed on the basis of gamma camera. Its basic structure consists of three major parts: the probe, the rotating motion frame, the computer and its auxiliary equipment. The probe of a SPECT device is the core of SPECT imaging. The main components of gamma camera imaging are collimator, large area NaI(Tl) scintillation crystal, light guide and PM tube array. Two features that differ from conventional NaI(Tl) counting detectors are critical for image formation. The first is that an imaging collimator is used to define the direction of detected gamma rays. Collimators most commonly consist of lead plates containing a large number of holes. By controlling which gamma rays are received, the collimator forms a projected image of the gamma ray distribution on the NaI(Tl) crystal surface. The second is that NaI(Tl) crystals are observed through an array of PM tubes rather than a single PM tube. The signal from the PM tube is fed to electronic or digital position logic circuits, which determine the XY position of each flash event by using a weighted average of the PM tube signal as each flash event occurs.

The output of each photomultiplier tube is amplified and digitized using an analog-to-digital converter (ADC). The XY position of each gamma ray interacting in the NaI(Tl) crystal was calculated from the digitized signal. The energy E of the gamma ray deposition is proportional to the total measured pulse amplitude and is also calculated by summing the individual PM tube signals. If E falls within the selected energy window, the event is accepted and placed at the appropriate XY position in the image.

The energy E of a single event can also be analyzed by summing the signals from all PM tubes. When the pulse amplitude of an event falls within the selected energy window, it is accepted and the X and Y values are merged into a discrete two-dimensional array of picture elements or pixels. The image is formed from a histogram of the number of events for each possible XY location. A large number of events are required to form an interpretable image, as each pixel must have a sufficient number of counts to achieve an acceptable level of signal-to-noise ratio.

The image is displayed on a computer monitor, where image brightness and contrast can be controlled, and different color representations can be used.

The problem with the prior art, however, is that typical gamma camera designs suffer from a typical defect that significantly affects image quality. First, in a typical gamma camera design, the edges of the collimator, scintillation crystal, light guide, and photoelectric conversion device array are aligned. That is, the left and right sides of the four-layer structure are aligned, just like the assembly method in FIG. 1 , such an arrangement is beneficial to the assembly of the device, but such a structure itself has problems.

The main problem with this structure is that the resulting image has very crowded edge bitmaps, which reduces the spatial resolution. In this design, image positioning is usually carried out through the so-called Light Sharing, the principle of which is shown in Figure 2. According to the design concept, with the different hit positions of the incident particles, the light emitted from each hit point propagates radioactively in the scintillation crystal, and is basically detected by the PMT close to or facing the hit position. The farther away PMTs are detected less, and in the analysis, according to the different ratios assigned to different photoelectric conversion devices, the location of the hit can be determined. In this analysis mode, there is basically no problem with the analysis around the hit point near the middle of the scintillation crystal, but for the case where the hit point is close to the edge, there are disadvantages. The light emitted after the hit will be reflected back by a large amount of light, forming a mirror image of the reflected light path, which will be captured by the PMT on the left. It is very dense, and because its location information is inaccurate, it does not actually reflect the detection information correctly.

At present, there is no technology for targeted improvement against this defect in the prior art. After investigations and inquiries in the field, it is generally believed that when the detection area of the detector is large enough, for example, it is much larger than the area of interest, even if there is such a Defects are not important and do not affect the actual effect of detection. Or think that the information at the general edge is not enough to be trusted, and it is not meaningful to improve it.

However, it is meaningful to improve this situation. If the cost is increased and the structural change is not too great, the effective improvement is made to overcome this problem, and the effective detection area (volume) of the detector will actually increase a lot. .

There is no such technology in the prior art, that is, how to make targeted improvements for the problems that the edge lattice is too crowded due to the existing structure design, and the spatial resolution of the image and the reliability of the edge portion are reduced.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the problem of over-crowded edge lattices caused by defects in the structural design of the existing gamma camera existing in the prior art, reducing the spatial resolution of the image and the availability of the edge portion. The problem of reliability, the device of the present application can make the same detection area, with little change in structure and cost, can obviously improve the problem that the dot matrix at the edge of the image is too dense and the reliability is low, or can It is more effective to increase the detection range, and this method does not require a large increase in instrument cost to complete.

A gamma camera detector with improved spatial resolution is characterized in that: it comprises a collimator layer, a scintillation crystal layer, a light guide layer, and a PMT array layer.

The cross-sections of the collimator layer and the scintillation crystal layer are the same, and the cross-sections of the optical guide layer and the PMT array layer are the same and larger than the cross-sectional area of the collimator layer. The order of the array layers is arranged adjacently from the outside to the inside.

A circle of extended light guides is closely arranged on the outer side of the scintillation crystal, and the extended light guide and the side surface of the scintillation crystal are coupled by optical glue or silicone oil, and are bonded together.

There is a circle of fillers above the extended light guide, and the fillers are located outside the light guide layer and the PMT array layer.

Further, the cross sections of the collimator layer, the scintillation crystal layer, the light guide layer, and the PMT array layer are all rectangular.

The collimator layer is a parallel hole collimator, a pinhole collimator, a diverging hole collimator or a focusing hole collimator with holes evenly arranged.

The material of the scintillation crystal layer is NaI(Tl) or CsI(Tl), and the PMT array layer is SiPMT; each PMT in the PMT array layer is connected to a conforming circuit.

The extended light guide is integrally formed, or a plurality of "L"-shaped or "one"-shaped light guide rods with a rectangular cross-section are spliced together.

The outside of the extended light guide is all painted black or all covered with a black reflective layer.

The lower surface area of the filler is smaller than the upper surface area of the extended light guide; and the outer edge of the filler and the outer edge of the extended light guide are rectangles with the same shape.

Further, the cross-sections of the collimator layer, the scintillation crystal layer, the light guide layer, and the PMT array layer are all square; the upper and lower sides of the extended light guide are all painted black or all black reflective layers are attached; the thickness of the filler is equal to The sum of the thickness of the optical guide layer and the PMT array layer.

Further, the lower surface of the filler and the inner surface of the detector housing are painted black or all covered with a black reflective layer; one or more gamma camera detectors are applied to one SPECT, and each gamma camera detector There is a positioning frame corresponding to it, and all positioning frames are installed on the same rotating frame.

A method for assembling a gamma camera detector with improved spatial resolution as described above (for the first type), characterized in that: (1) opening the lower surface of the detector shell, and sequentially assembling the filler (2) Put the PMT array layer into the top of the detector housing and fix it, and lead out the wires and data lines of the PMT array layer from the upper side; (3) Install the light guide layer, The scintillation crystal layer and the collimator layer, and the PMT array layer and the light guide layer, the scintillation crystal layer, and the collimator layer are closely attached and fixed in turn, and the extended light guide and the side of the scintillation crystal are coupled by optical glue or silicone oil, and pasted. Put them together; (4) Confirm that the components are tightly combined, and power on to check the image acquisition function.

There is also a gamma camera detector with improved spatial resolution, which is characterized in that it includes a collimator layer, a scintillation crystal layer, a light guide layer, and a PMT array layer. The gamma camera detector is considered the second type.

The cross-sections of the collimator layer and the scintillation crystal layer are the same, and the cross-sections of the optical guide layer and the PMT array layer are the same and larger than the cross-sectional area of the collimator layer. The order of the array layers is arranged adjacently from the outside to the inside.

A circle of extended light guides is closely arranged on the outer side of the scintillation crystal, and the extended light guide and the side surface of the scintillation crystal are coupled by optical glue or silicone oil, and are bonded together.

Further, the cross sections of the collimator layer, the scintillation crystal layer, the light guide layer and the PMT array layer are all rectangular.

The collimator layer is a parallel hole collimator, a pinhole collimator, a diverging hole collimator or a focusing hole collimator with holes evenly arranged.

The material of the scintillation crystal layer is NaI(Tl) or CsI(Tl), and the PMT array layer is SiPMT; each PMT in the PMT array layer is connected to a conforming circuit.

The extended light guide is integrally formed, or a plurality of "L"-shaped or "one"-shaped light guide rods with a rectangular cross-section are spliced together. After the scintillation crystal layer is closely arranged with a circle of extended light guides on the outside, the overall cross section is consistent with the cross section of the PMT array layer. The outside of the extended light guide is all painted black or all covered with a black reflective layer.

Further, the cross sections of the collimator layer, the scintillation crystal layer, the light guide layer, and the PMT array layer are all square; the upper and lower sides of the extended light guide are all painted black or all covered with black reflective layers.

Further, the inner surface of the detector housing is painted black or all covered with a black reflective layer; one or more gamma camera detectors are applied to a SPECT, and each gamma camera detector has a positioning frame with it. Correspondingly, all positioning frames are installed on the same rotating frame.

A method for assembling a gamma camera detector with improved spatial resolution as described above (for the second type), characterized in that: (1) the lower surface of the detector housing is opened, and the PMT array layer is opened. Insert it at the top and fix it, and pull out the wires and data lines of the PMT array layer from the upper side; (2) Put the light guide layer into the detector housing, so that the upper surface is close to the lower surface of the PMT array and fixed; ( 3) Coupling between the extended light guide and the side of the scintillation crystal through optical glue or silicone oil, and stick them together, put it into the detector shell, and make the upper surface close to the lower surface of the light guide layer and fix it; (4) Installation Align the upper surface of the collimator layer with the lower surface of the scintillation crystal, and fix it; (5) Confirm that the components are tightly combined, and energize to check the image acquisition function.

The advantages of the present invention can be mainly divided into the following points. First, on the premise that the cost is basically not increased (the price of the extended light guide is not high, especially compared with the scintillation crystal, the price is low), the edge of the existing SPECT image is basically solved. The lattice is too crowded, which reduces the spatial resolution of the image and the reliability of the edge part; the second is that, without changing the scintillation crystal, only by expanding the setting of the light guide and the relative expansion of the PMT array, not only the SPECT image can be solved The edge lattice is too crowded, and it can effectively expand the effective image collection area, at least expand the range of the thickness of the extended light guide on each side, for example, 5-15cm, which increases the overall collection area considerably. The third is that this improvement was completed under the premise of a very limited increase in cost (without adding scintillation crystals, only by increasing part of the PMT array and increasing the light guide arrangement at the edge), under the premise of improving the existing defects At the same time, the effective detection range has been increased and improved, which can be said to be a double-blind solution.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other similar implementation drawings can also be obtained from these drawings without creative efforts.

Figure 1 is a schematic diagram of a general SPECT setup.

FIG. 2 is a schematic diagram of the effect of a first typical embodiment of the present invention.

FIG. 3 is a schematic diagram of the effect of a second typical embodiment of the present invention.

Reference numerals: SPECT system, 1, detection group, 11, detector, 21, coincidence circuit, 22, computer, 211, collimator layer, 212, scintillation crystal layer, 213, light guide layer, 214, PMT array layer, 215, extended light guide, 216, filler; 4, rotating frame, 42, positioning frame, 5, region of interest, 81, photoelectric converter array; 82, light guide; 83, scintillation crystal; 84, collimator;

Detailed ways

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, and the protection scope of the present invention can be more clearly defined.

Fig. 2 shows the setting method of the effect of the first typical implementation example of the present invention. On the one hand, the extended light guide arranged on the side is used to extract most of the light that may have been reflected before, and at the same time, the light generated by a part of the hitting point is considered. Astigmatism may be emitted farther out than the original PMT array, so the light guide layer and PMT array layer are appropriately widened, so that the widened light guide layer and PMT array layer can effectively increase the effective detection of the detector. Area (as shown in the light sharing shown in Figure 2), the setting in Figure 2 not only improves the existing defects of dense dot matrix and inaccurate information at the edge of the image, but also the part of the light that was originally reflected back and was inaccurately positioned The phenomenon of sharing can be effectively located, the image detection range can be expanded, and the effective detection range has been improved. In this case, the width of the PMT array and the light guide layer is generally not as wide as that of the extended light guide, and a filler needs to be provided above the extended light guide to partially fill the cavity and protect the components. This method can be used in cases where you just want to overcome the defect of dense edge lattices.

Fig. 3 shows the setting method of the effect of another typical implementation example of the present invention. On the one hand, the extended light guide arranged on the side is used to extract most of the light that may be reflected originally, and at the same time, the light generated by a part of the hitting point is considered. Astigmatism may be emitted to a position farther out than the original PMT array, or even a very far position, so the optical guide layer and the PMT array layer are greatly widened, so that this part of the widened optical guide layer and PMT array layer can be compared. The effective detection area of the detector is greatly increased (as shown in the light sharing shown in Figure 3). The setting of Figure 3 not only improves the existing defects of dense dot matrix and inaccurate information at the edge of the image, but also reflects the original image. Come back, the phenomenon of light sharing with inaccurate positioning can be effectively located, which can greatly expand the image detection range, and greatly increase the effective detection range. The effective detection range in this case is significantly larger than the case in Figure 2, but the PMT array and the light guide layer are obviously set larger, which requires a certain extra cost. But compared to the setting of scintillation crystals, the cost is still limited.

Example 1

A gamma camera detector with improved spatial resolution is characterized in that: it includes a collimator layer 211 , a scintillation crystal layer 212 , a light guide layer 213 , and a PMT array layer 214 .

The cross-sections of the collimator layer 211 and the scintillation crystal layer 212 are the same, and the cross-sections of the light guide layer 213 and the PMT array layer 214 are the same and larger than the cross-sectional area of the collimator layer. 212 , the light guide layer 213 , and the PMT array layer 214 are arranged adjacently in sequence from the outside to the inside. The configuration method here is that the cross-sectional area of the light guide layer and the PMT array layer are the same, and they are larger than the collimator layer and the scintillation crystal layer. If the inside is rectangular, the outer rectangular tube should also be larger. , if the inside is a square, the outside should also be larger. For the convenience of operation, the difference of the side length is, for example, an integer multiple of the PMT unit, which is easy to handle. Light guides and extended light guides can be arranged in coordination.

A circle of extended light guides is closely arranged on the outer side of the scintillation crystal, and the extended light guide and the side surface of the scintillation crystal are coupled by optical glue or silicone oil, and are bonded together. Because there is auxiliary fixing on the outside of the extended light guide, the coupling here only needs to have a certain binding force between the two.

There is a circle of fillers above the extended light guide, and the fillers are located outside the light guide layer and the PMT array layer. The filler is set to prevent the whole detector from shaking and shaking, and it can be one of various polyester materials, teflon can be selected, or other polyester materials commonly used in the field for support, preferably harmless, It has certain temperature resistance, and it is hard and the surface is not easy to peel off, such as polypropylene, modified polyurethane, PMMA, rigid polyurethane, rigid polyester fiber, dense foamed polyester fiber board, etc.

Further, the cross sections of the collimator layer, the scintillation crystal layer, the light guide layer, and the PMT array layer are all rectangular.

The collimator layer is a parallel hole collimator, a pinhole collimator, a diverging hole collimator or a focusing hole collimator with holes evenly arranged. Parallel holes are preferred, for example, other types are also possible, or other popular types suitable for spectroscopy.

The material of the scintillation crystal layer is NaI(Tl) or CsI(Tl), and the PMT array layer is SiPMT or ordinary PMT; each PMT in the PMT array layer is connected to a conforming circuit.

The extended light guide is integrally formed, or a plurality of "L"-shaped or "one"-shaped light guide rods with a rectangular cross-section are spliced together. For example, it is composed of 8-12 straight rod-shaped light guide rods, and both ends of the corner are cut into an oblique angle in advance, or four L-shaped rods at the four corners are assembled with 1-3 light guide rods in between, or it can be a whole the light guide circle.

The outside of the extended light guide is all painted black or all covered with a black reflective layer. Here, a commercially available coating layer or a reflective adhesive layer may be used.

The lower surface area of the filler is smaller than the upper surface area of the extended light guide; and the outer edge of the filler and the outer edge of the extended light guide are rectangles with the same shape. This is precisely because the filler is used to fill the space above.

Further, the cross-sections of the collimator layer 211, the scintillation crystal layer 212, the light guide layer 213, and the PMT array layer 214 are all square; the upper and lower sides of the extended light guide are all painted black or all affixed with black reflective layers; filling The thickness of the element is equal to the sum of the thicknesses of the light guide layer and the PMT array layer.

Further, the lower surface of the filler and the inner surface of the detector housing are painted black or all covered with a black reflective layer; one or more gamma camera detectors are applied to one SPECT, and each gamma camera detector There is a positioning frame corresponding to it, and all positioning frames are installed on the same rotating frame. For example, the positioning frame preferably includes the detector on the outside, and the rotating frame is further fixed on the outside, at least four edges of the detector are fixed and fixed firmly, otherwise the movement and rotation cannot be realized.

A method for assembling a gamma camera detector with improved spatial resolution as described above (for the first type), characterized in that: (1) opening the lower surface of the detector shell, and sequentially assembling the filler (2) Put the PMT array layer into the top of the detector housing and fix it, and lead out the wires and data lines of the PMT array layer from the upper side; (3) Install the light guide layer, The scintillation crystal layer and the collimator layer, and the PMT array layer and the light guide layer, the scintillation crystal layer, and the collimator layer are closely attached and fixed in turn, and the extended light guide and the side of the scintillation crystal are coupled by optical glue or silicone oil, and pasted. Put them together; (4) Confirm that the components are tightly combined, and power on to check the image acquisition function. This embodiment corresponds to FIG. 2 .

Example 2

There is also a gamma camera detector with improved spatial resolution, which is characterized in that it includes a collimator layer, a scintillation crystal layer, a light guide layer, and a PMT array layer. The gamma camera detector is considered the second type.

The cross-sections of the collimator layer and the scintillation crystal layer are the same, and the cross-sections of the optical guide layer and the PMT array layer are the same and larger than the cross-sectional area of the collimator layer. The order of the array layers is arranged adjacently from the outside to the inside. The configuration method here is that the cross-sectional area of the light guide layer and the PMT array layer are the same, and they are larger than the collimator layer and the scintillation crystal layer. If the inside is rectangular, the outer rectangular tube should also be larger. , if the inside is a square, the outside should also be larger. For the convenience of operation, the difference of the side length is, for example, an integer multiple of the PMT unit, which is easy to handle. Light guides and extended light guides can be arranged in coordination.

A circle of extended light guides is closely arranged on the outer side of the scintillation crystal, and the extended light guide and the side surface of the scintillation crystal are coupled by optical glue or silicone oil, and are bonded together. Because there is auxiliary fixing on the outside of the extended light guide, the coupling here only needs to have a certain binding force between the two.

Further, the cross sections of the collimator layer, the scintillation crystal layer, the light guide layer and the PMT array layer are all rectangular.

The collimator layer is a parallel hole collimator, a pinhole collimator, a diverging hole collimator or a focusing hole collimator with holes evenly arranged. Parallel holes are preferred, for example, other types are also possible, or other popular types suitable for spectroscopy.

The material of the scintillation crystal layer is NaI(Tl) or CsI(Tl), and the PMT array layer is SiPMT; each PMT in the PMT array layer is connected to a conforming circuit. The arrangement of the conforming circuit is similar to other settings in the field. When the resolution is purchased, each unit can be calculated and output separately. The resolution requirement is low, and 2*2, 3*3 can be combined for calculation.

The extended light guide is integrally formed, or a plurality of "L"-shaped or "one"-shaped light guide rods with a rectangular cross-section are spliced together. After the scintillation crystal layer is closely arranged with a circle of extended light guides on the outside, the overall cross section is consistent with the cross section of the PMT array layer. For example, it is composed of 8-12 straight rod-shaped light guide rods, and both ends of the corner are cut into an oblique angle in advance, or four L-shaped rods at the four corners are assembled with 1-3 light guide rods in between, or it can be a whole the light guide circle. The outside of the extended light guide is all painted black or all covered with a black reflective layer.

Further, the cross sections of the collimator layer, the scintillation crystal layer, the light guide layer, and the PMT array layer are all square; the upper and lower sides of the extended light guide are all painted black or all covered with black reflective layers. Here, a commercially available coating layer or a reflective adhesive layer may be used.

Further, the inner surface of the detector housing is painted black or all covered with a black reflective layer; one or more gamma camera detectors are applied to a SPECT, and each gamma camera detector has a positioning frame with it. Correspondingly, all positioning frames are installed on the same rotating frame.

A method for assembling a gamma camera detector with improved spatial resolution as described above (for the second type), characterized in that: (1) the lower surface of the detector housing is opened, and the PMT array layer is opened. Insert it at the top and fix it, and pull out the wires and data lines of the PMT array layer from the upper side; (2) Put the light guide layer into the detector housing, so that the upper surface is close to the lower surface of the PMT array and fixed; ( 3) Coupling between the extended light guide and the side of the scintillation crystal through optical glue or silicone oil, and stick them together, put it into the detector shell, and make the upper surface close to the lower surface of the light guide layer and fix it; (4) Installation Align the upper surface of the collimator layer with the lower surface of the scintillation crystal, and fix it; (5) Confirm that the components are tightly combined, and energize to check the image acquisition function. This embodiment corresponds to FIG. 3 .

Example 3

The difference between this embodiment and Embodiment 1 is that neither the light guide layer nor the PMT array layer is widened, and the collimator layer 211 , the scintillation crystal layer 212 , the light guide layer 213 , and the PMT array layer 214 remain as they were before the improvement, so that the detection area is It doesn't get bigger, it's just that the inaccuracies of dense lattice at the edges are overcome, which is the easiest way to improve when you're on a tight budget. Others are the same as in Example 1

Example 4

The difference between this embodiment and Embodiment 2 is that the light guide layer 213 , the PMT array layer, and the extended light guide are further widened. For example, the PMT array layer has 4 layers, 5 layers, and 6 layers more at each edge. There is no change, this can increase the effective detection range is limited, generally there may be about 6-7 more layers on each edge of the PMT array layer, the effective detection range cannot be increased any more, only the width of the scintillation crystal can be increased to increase.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited to this, and any changes or substitutions that are not conceived of without creative work should be included within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope defined by the claims.

Claims (10)

1. A gamma camera detector for improving spatial resolution, comprising:

the device comprises a collimator layer (211), a scintillation crystal layer (212), a light guide layer (213) and a PMT array layer (214);

the cross sections of the collimator layer (211) and the scintillation crystal layer (212) are consistent, the cross sections of the light guide layer (213) and the PMT array layer (214) are consistent and are larger than the cross section area of the collimator layer, and the light guide layer (211), the scintillation crystal layer (212), the light guide layer (213) and the PMT array layer (214) are sequentially adjacently arranged from outside to inside according to the sequence of the collimator layer (211), the scintillation crystal layer (212), the light guide layer (213) and the PMT array layer (214);

a circle of extension light guide is arranged on the outer side of the scintillation crystal in a clinging manner, and the extension light guide is coupled with the side surface of the scintillation crystal through optical cement or silicon oil and is clinged together;

a ring of filler is provided over the extended light guide, the filler being located outside the light guide layer and the PMT array layer.

2. The gamma camera detector of claim 1, wherein:

the cross sections of the collimator layer, the scintillation crystal layer, the light guide layer and the PMT array layer are all rectangular;

the collimator layer is a parallel hole collimator, a pinhole collimator, a divergent hole collimator or a focused hole collimator with uniformly distributed holes;

the material of the scintillation crystal layer is NaI (Tl) or CsI (Tl), and the PMT array layer is SiPMT; each PMT in the PMT array layer is connected with a coincidence circuit;

the extension light guide is integrally formed or formed by splicing a plurality of light guide rods with L-shaped or I-shaped cross sections and rectangular cross sections;

the outer side of the extended light guide is completely blackened or is completely attached with a black reflecting layer;

the lower surface area of the filler is smaller than the upper surface area of the extended light guide; and the outer edge of the filler piece and the outer edge of the extended light guide are rectangles of the same shape.

3. The gamma camera detector of claim 2, wherein:

the cross sections of the collimator layer (211), the scintillation crystal layer (212), the light guide layer (213) and the PMT array layer (214) are all square;

the upper side and the lower side of the extended light guide are completely blackened or completely pasted with black reflecting layers;

the thickness of the filler is equal to the sum of the thicknesses of the light guide layer and the PMT array layer.

4. A gamma camera detector for improving spatial resolution as claimed in claim 3, wherein:

the lower surface of the filling piece and the inner surface of the detector shell are both coated with black or are completely pasted with black reflecting layers;

one or more gamma camera detectors are applied to a SPECT, and each gamma camera detector has a positioning frame corresponding to it, all mounted on the same rotating gantry.

5. A method of assembling a gamma camera detector with improved spatial resolution as claimed in claim 3 or 4, wherein:

(1) Opening the lower surface of the detector shell, and sequentially plugging the filling piece and the extended light guide into the edge and fixing;

(2) Putting the PMT array layer into the top of the detector shell and fixing, and leading out the electric wires and the data wires of the PMT array layer from the upper side;

(3) The light guide layer, the scintillation crystal layer and the collimator layer are sequentially arranged, the PMT array layer, the light guide layer, the scintillation crystal layer and the collimator layer are sequentially and closely attached and fixed, and the side surfaces of the extension light guide and the scintillation crystal are coupled through optical cement or silicone oil and are attached together;

(4) And confirming that all parts are tightly combined, and electrifying to check the image acquisition function.

6. A gamma camera detector for improving spatial resolution, comprising:

the device comprises a collimator layer (211), a scintillation crystal layer (212), a light guide layer (213) and a PMT array layer (214);

the cross sections of the collimator layer (211) and the scintillation crystal layer (212) are consistent, the cross sections of the light guide layer (213) and the PMT array layer (214) are consistent and are larger than the cross section area of the collimator layer, and the light guide layer (211), the scintillation crystal layer (212), the light guide layer (213) and the PMT array layer (214) are sequentially adjacently arranged from outside to inside according to the sequence of the collimator layer (211), the scintillation crystal layer (212), the light guide layer (213) and the PMT array layer (214);

and a circle of extension light guide is closely arranged on the outer side of the scintillation crystal, and the extension light guide is coupled with the side surface of the scintillation crystal through optical cement or silicon oil and is attached together.

7. The gamma camera detector of claim 6, wherein:

the cross sections of the collimator layer, the scintillation crystal layer, the light guide layer and the PMT array layer are all rectangular;

the collimator layer is a parallel hole collimator, a pinhole collimator, a divergent hole collimator or a focused hole collimator with uniformly distributed holes;

the material of the scintillation crystal layer is NaI (Tl) or CsI (Tl), and the PMT array layer is SiPMT; each PMT in the PMT array layer is connected with a coincidence circuit;

the extension light guide is integrally formed or formed by splicing a plurality of L-shaped or I-shaped light guide rods with rectangular cross sections;

after a circle of extension light guide is arranged on the outer side of the scintillation crystal layer in a clinging manner, the whole cross section is consistent with that of the PMT array layer;

the outer side of the extended light guide is either completely blackened or completely covered with a black reflective layer.

8. The gamma camera detector for improving spatial resolution of claim 7, wherein:

the cross sections of the collimator layer (211), the scintillation crystal layer (212), the light guide layer (213) and the PMT array layer (214) are square;

the upper and lower sides of the extended light guide are either completely blackened or completely coated with a black reflective layer.

9. The gamma camera detector of claim 8, wherein:

the inner surface of the detector shell is coated with black or is completely pasted with a black reflecting layer;

one or more gamma camera detectors are applied to a SPECT, and each gamma camera detector has a positioning frame corresponding to it, all mounted on the same rotating gantry.

10. A method of assembling a gamma camera detector for improved spatial resolution as claimed in claim 8 or 9, wherein:

(1) Opening the lower surface of the detector shell, plugging the PMT array layer into the uppermost part and fixing, and leading out the electric wires and the data wires of the PMT array layer from the upper side;

(2) Putting the light guide layer into a detector shell, and enabling the upper surface of the light guide layer to be tightly attached to the lower surface of the PMT array and fixed;

(3) Coupling the side surfaces of the extension light guide and the scintillation crystal through optical cement or silicon oil, attaching the extension light guide and the scintillation crystal together, and putting the extension light guide and the scintillation crystal into a detector shell to ensure that the upper surface of the extension light guide is tightly attached to the lower surface of the light guide layer and fixed;

(4) Mounting a collimator layer, aligning the upper surface of the collimator layer with the lower surface of the scintillation crystal, and fixing;

(5) Confirming that all parts are tightly combined, and electrifying to check the image acquisition function.

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