Method and system for generating mapping table of interaction positions between crystal bars and gamma photons

Abstract

The present invention provides a method and system for generating a mapping table of the interaction position between a crystal bar and gamma photons. By continuously mapping a crystal array with a point source or a general source, calculating the signals received by PMTs, and obtaining a scatter plot reflecting the interaction position of coincidence events. After removing the singular points in the two-dimensional position spectrum through digital processing, the local maximum algorithm is used for the two-dimensional position spectrum to estimate the center position of each crystal bar, and the data is binarized to obtain a binarized position map. The Euclidean distance from each pixel point to the nearest bright point is calculated for the binarized position map to obtain a distance distribution map. The local maximum values of the distance distribution map are obtained along the X direction and the Y direction respectively to divide the boundary positions of each crystal bar. In this way, each region corresponds one-to-one with the crystal bar array, and then the position mapping table of the system is determined. This method can cover all positions and there will be no divided dead zones.

Description

Technical Field

[0001] The present invention belongs to the technical field of positron emission tomography, and particularly relates to a method and system for generating a mapping table of the interaction position between crystal bars and gamma photons. Background Art

[0002] Positron emission tomography (PET) is a novel three-dimensional nuclear medicine imaging technique and belongs to a type of emission tomography. It uses positron radionuclides labeled with human metabolites such as glucose as imaging agents, and reflects the metabolic changes by the uptake of the imaging agent by lesions, providing biological metabolic information of diseases. It can diagnose and guide the treatment of various diseases earlier, more sensitively, and accurately, and has important application values in biology, neuroscience, oncology, pharmacokinetics, clinical diagnosis, and treatment evaluation. Its basic principle is to inject a trace amount of positron radionuclide tracer into the human body. The positron annihilates with the negative electron in the human body to generate a pair of gamma photons emitted back to back. An external detection device is used to detect this pair of photons to detect the distribution of the radioactive drug in the body. The currently commonly used detector system is realized by coupling a crystal array composed of crystal bars with photomultiplier tubes. When the gamma photons generated by the annihilation of positive and negative electrons enter the crystal bar and react with the crystal, fluorescence will be generated when the crystal atoms de-excite. The fluorescence propagates along the crystal array and is then converted into an electrical signal by the photomultiplier tube. This electrical signal carries the position information of the incident gamma photon. The position information of the crystal bar where the incident gamma photon reacts is obtained by using a positioning algorithm, so as to determine the position of the coincidence line of the annihilation event. The accuracy of the position information will directly affect the spatial resolution of the detector, and further affect the imaging quality of PET and the accuracy of image quantitative analysis. Therefore, the accurate positioning of the crystal bar where the gamma photon undergoes energy deposition is crucial.

[0003] However, in fact, due to differences in the arrangement of scintillation crystals, the cutting method of the light-splitting light guide, the signal processing ability of photomultiplier tubes, and the front-end electronic signal acquisition circuit, etc., the position information calculated by the positioning algorithm is prone to distortion, so corresponding position mapping algorithms must be used for correction. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention aims to provide a method for generating a mapping table of the interaction position between a crystal bar and a gamma photon, including the following steps: Step 1: Perform two-dimensional statistics on the position information of incident photon events to obtain a two-dimensional position spectrum, where the brightness of each pixel point in the two-dimensional position spectrum represents the number of events at that position; Step 2: Perform median filtering on the obtained two-dimensional position spectrum using a 3*3 two-dimensional template; Step 3: Perform mean filtering on the two-dimensional position spectrum along the X direction and the Y direction respectively using 1*3 and 3*1 templates; Step 4: Estimate the center position of each crystal bar for the two-dimensional position spectrum using the local maximum algorithm, and perform binarization processing on the data to obtain a binarized position map; Step 5: Calculate the Euclidean distance from each pixel point in the binarized position map to the nearest bright point to obtain a distance distribution map; Step 6: Find the local maximum values of the distance distribution map along the X direction and the Y direction respectively and divide the boundary positions of each crystal bar; Step 7: Use the region identification algorithm to correspond each region to the crystal bar number one by one to complete the mapping relationship between the scatter plot and the crystal bar; and Step 8: Use the boundary extraction position mapping algorithm to generate a position mapping table.

[0005] According to the above-mentioned method for generating a mapping table of the interaction position between a crystal bar and a gamma photon of the present invention, further, the above-mentioned Step 4 includes: performing one-dimensional peak searching on the two-dimensional position spectrum in the X direction and the Y direction respectively; performing an "AND operation" on the peak searching results in the X direction and the Y direction at the same pixel point. If the pixel point is a peak point in both the X direction and the Y direction at the same time, then set the pixel point value to 1, otherwise set it to 0, thus completing the binarization processing.

[0006] According to the above-mentioned method for generating a mapping table of the interaction position between a crystal bar and a gamma photon of the present invention, further, the above-mentioned Step 6 includes: performing one-dimensional peak searching on the distance distribution map along the X direction and the Y direction respectively using the derivative peak searching method; performing an "OR operation" on the peak searching results in the X direction and the Y direction at the same pixel point, and the position corresponding to the maximum value corresponds to the boundary positions of each crystal bar to obtain a boundary position distribution map.

[0007] According to the above-mentioned method for generating a mapping table of the interaction position between a crystal bar and a gamma photon of the present invention, further, the above-mentioned Step 7 includes: region identification, boundary attribution, and sequential coding.

[0008] According to the above-mentioned method for generating a mapping table of the interaction position between a crystal bar and a gamma photon of the present invention, further, the region identification includes: performing region identification on the boundary position distribution map, and the formed region identification is not encoded in sequence but randomly. Only calculate which pixel points belong to the same region, and the pixel points belonging to the same region use the same code, and the codes between each region are ensured not to repeat.

[0009] According to the method for generating a mapping table of the interaction position between a crystal bar and gamma photons described above in the present invention, further, the boundary attribution includes: when determining the region attribution of the pixel points corresponding to the boundary positions, according to the characteristics of the one-dimensional peak search algorithm used for finding local maxima in the distance distribution map, the boundary attribution is determined according to the following rules: the boundary points along the X direction belong to the region on the right side of the boundary, and the boundary points along the Y direction belong to the region below the boundary.

[0010] According to the method for generating a mapping table of the interaction position between a crystal bar and gamma photons described above in the present invention, further, the sequential coding includes using a sequential coding algorithm to make each region correspond to the coding sequence of the crystal table, thereby completing the mapping relationship between the scatter plot and the crystal bar.

[0011] The present invention also provides a system for generating a mapping table of the interaction position between a crystal bar and gamma photons, including an array crystal, a data statistics detector, a median filtering processor, an average filtering processor, a central position estimation module of the crystal bar, a distance calculation module, a crystal bar boundary determination module, a region identification module, a boundary attribution module, a region sequential encoder, a position mapping table generation module, and a position mapping table output module. The array crystal has multiple crystal bars. The data statistics detector is coupled with the array crystal. The data statistics detector, the median filtering processor, the average filtering processor, the central position estimation module of the crystal bar, the distance calculation module, the crystal bar boundary determination module, the region identification module, the boundary attribution module, the region sequential encoder, the position mapping table generation module, and the position mapping table output module are connected in sequence.

[0012] According to the system for generating a mapping table of the interaction position between a crystal bar and gamma photons described above in the present invention, further, the data statistics detector is a PET detector.

[0013] According to the system for generating a mapping table of the interaction position between a crystal bar and gamma photons described above in the present invention, further, both the median filtering processor and the average filtering processor are Gaussian filtering processors.

[0014] According to the system for generating a mapping table of the interaction position between a crystal bar and gamma photons described above in the present invention, further, the median filtering processor is a median filtering processor with a 3*3 two-dimensional template.

[0015] According to the system for generating a mapping table of the interaction position between a crystal bar and gamma photons described above in the present invention, further, the average filtering processor includes an X-direction average filtering processor and a Y-direction average filtering processor. The X-direction average filtering processor and the Y-direction average filtering processor are both connected to the median filtering processor and the central position estimation module of the crystal bar. The X-direction average filtering processor is an average filtering processor with a 1*3 template, and the Y-direction average filtering processor is an average filtering processor with a 3*1 template.

[0016] According to the above-mentioned system for generating a mapping table of the interaction position between a crystal bar and gamma photons of the present invention, further, the central position estimation module of the crystal bar has an "AND operation" processor and a binarization processor, and the "AND operation" processor and the binarization processor are integrally connected in series to the central position estimation module of the crystal bar.

[0017] According to the above-mentioned system for generating a mapping table of the interaction position between a crystal bar and gamma photons of the present invention, further, the distance calculation module is an Euclidean distance calculator.

[0018] According to the above-mentioned system for generating a mapping table of the interaction position between a crystal bar and gamma photons of the present invention, further, the crystal bar boundary determination module includes an X-direction one-dimensional peak search unit, a Y-direction one-dimensional peak search unit, and an "OR operation" processor. The X-direction one-dimensional peak search unit, the Y-direction one-dimensional peak search unit, and the "OR operation" processor are integrated into the crystal bar boundary determination module. Both ends of the X-direction one-dimensional peak search unit and the Y-direction one-dimensional peak search unit are respectively connected to the distance calculation module and the "OR operation" processor, and the other end of the "OR operation" processor is connected to the region identification module.

[0019] According to the above-mentioned system for generating a mapping table of the interaction position between a crystal bar and gamma photons of the present invention, further, the encoder of the region identification module is a random encoder. Brief Description of the Drawings

[0020] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above technical solution, other features and advantages of the present invention more obvious and understandable, the following preferred embodiments are specifically given and described in detail in conjunction with the drawings as follows.

[0021] Figure 1 is a schematic structural diagram of a system for generating a mapping table of the interaction position between a crystal bar and gamma photons disclosed by the present invention;

[0022] Figure 2 is a schematic structural diagram of the central position estimation module of the crystal bar of a system for generating a mapping table of the interaction position between a crystal bar and gamma photons disclosed by the present invention. In addition, the connection relationship between the median filtering processor, the mean filtering processor, the central position estimation module of the crystal bar, and the distance calculation module is shown in the figure. The rest of the system is Figure 1 similar and is omitted;

[0023] Figure 3 is a schematic structural diagram of the crystal bar boundary determination module of a system for generating a mapping table of the interaction position between a crystal bar and gamma photons disclosed by the present invention. In addition, the connection relationship between the distance calculation module, the crystal bar boundary determination module, and the region identification module is shown in the figure. The rest of the system is Figure 1Similar and omitted;

[0024] Figure 4 It is a flowchart of a method for generating a mapping table of the interaction position between a crystal bar and gamma photons disclosed by the present invention;

[0025] Figure 5 It is a two-dimensional position spectrum obtained statistically in a method for generating a mapping table of the interaction position between a crystal bar and gamma photons disclosed by the present invention, that is, a scatter plot;

[0026] Figure 6 It is the peak search result of the scatter plot along the X direction in a method for generating a mapping table of the interaction position between a crystal bar and gamma photons disclosed by the present invention;

[0027] Figure 7 It is the peak search result of the scatter plot along the Y direction in a method for generating a mapping table of the interaction position between a crystal bar and gamma photons disclosed by the present invention;

[0028] Figure 8 It is a central position map of the crystal bar estimated in a method for generating a mapping table of the interaction position between a crystal bar and gamma photons disclosed by the present invention, that is, a binary position spectrum;

[0029] Figure 9 It is a distance distribution map in a method for generating a mapping table of the interaction position between a crystal bar and gamma photons disclosed by the present invention, only showing the Figure 8 local distance distribution map corresponding to the A region shown in;

[0030] Figure 10 It is a result display map of boundary division in a method for generating a mapping table of the interaction position between a crystal bar and gamma photons disclosed by the present invention;

[0031] Figure 11 It is for Figure 10 the crystal efficiency display map of each partition after boundary division in;

[0032] Figure 12 It is a position mapping table in a method for generating a mapping table of the interaction position between a crystal bar and gamma photons disclosed by the present invention, only showing the Figure 10 partial position mapping table corresponding to the B region shown in. Specific embodiments

[0033] Next, in combination with the accompanying drawings and specific embodiments, the present invention will be further described:

[0034] As Figure 1As shown in the figure, the present invention provides a system for generating a mapping table of the interaction position between a crystal bar and gamma photons, which includes an array crystal 01, a data statistics detector 02, a median filtering processor 03, mean filtering processors 04 and 05, a central position estimation module 06 of the crystal bar, a distance calculation module 07, a crystal bar boundary determination module 08, a region identification module 09, a boundary attribution module 10, a region sequence encoder 11, a position mapping table generation module 12, and a position mapping table output module 13. The array crystal 01 has a plurality of crystal bars (not shown in the figure). The data statistics detector 02 is coupled to the array crystal 01. The data statistics detector 02, the median filtering processor 03, the mean filtering processors 04 and 05, the central position estimation module 06 of the crystal bar, the distance calculation module 07, the crystal bar boundary determination module 08, the region identification module 09, the boundary attribution module 10, the region sequence encoder 11, the position mapping table generation module 12, and the position mapping table output module 13 are connected in sequence.

[0035] According to the above-mentioned system for generating a mapping table of the interaction position between a crystal bar and gamma photons of the present invention, further, the data statistics detector 02 is a PET detector. In an embodiment of the present invention, an 8*8 BGO array crystal and a PET detector coupled with Hamamatsu PMT are used for data acquisition. The data statistics detector 02 detects the time position distribution of incident photons and displays the position distribution map in an image of 64*64 pixels. As Figure 5 shown, the total number of incident photons in terms of time is 736,124.

[0036] In addition, according to the above-mentioned system for generating a mapping table of the interaction position between a crystal bar and gamma photons of the present invention, further, the median filtering processor 03 and the mean filtering processors 04 and 05 are all Gaussian filtering processors. The median filtering processor 03 is a median filtering processor with a 3*3 two-dimensional template. The mean filtering processors 04 and 05 include an X-direction mean filtering processor 04 and a Y-direction mean filtering processor 05. The X-direction mean filtering processor 04 and the Y-direction mean filtering processor 05 are both connected to the median filtering processor 03 and the central position estimation module 06 of the crystal bar. The X-direction mean filtering processor 04 is a mean filtering processor with a 1*3 template, and the Y-direction mean filtering processor 05 is a mean filtering processor with a 3*1 template.

[0037] As Figure 2 shown, according to the above-mentioned system for generating a mapping table of the interaction position between a crystal bar and gamma photons of the present invention, further, the central position estimation module 06 of the crystal bar has an "AND operation" processor 14 and a binarization processor 15. The "AND operation" processor 14 and the binarization processor 15 are integrally connected in series to the central position estimation module 06 of the crystal bar.

[0038] According to the above-mentioned system for generating a mapping table of the interaction position between a crystal bar and gamma photons according to the present invention, further, the distance calculation module 07 is an Euclidean distance calculator.

[0039] As Figure 3 shown, according to the above-mentioned system for generating a mapping table of the interaction position between a crystal bar and gamma photons according to the present invention, further, the crystal bar boundary determination module 08 includes an X-direction one-dimensional peak searching unit 16, a Y-direction one-dimensional peak searching unit 17, and an "OR operation" processor 18. The X-direction one-dimensional peak searching unit 16, the Y-direction one-dimensional peak searching unit 17, and the "OR operation" processor 18 are integrated into the crystal bar boundary determination module 08. Both ends of the X-direction one-dimensional peak searching unit 16 and the Y-direction one-dimensional peak searching unit 17 are respectively connected to the distance calculation module 07 and the "OR operation" processor 18. The other end of the "OR operation" processor 18 is connected to the region identification module 09, and the encoder of the region identification module 09 is a random encoder.

[0040] As Figure 4 shown, a method for generating a mapping table of the interaction position between a crystal bar and gamma photons according to the present invention includes the following steps:

[0041] Step 1: The data statistical detector 02 performs two-dimensional statistics on the position information of incident photon events to obtain a two-dimensional position spectrum, that is, a scatter plot. As Figure 5 shown, the brightness of each pixel point in the two-dimensional position spectrum represents the number of events at that position.

[0042] Step 2: The median filtering processor 03 performs median filtering on the obtained two-dimensional position spectrum using a 3×3 two-dimensional template.

[0043] Step 3: The X-direction mean filtering processor 04 and the Y-direction mean filtering processor 05 respectively perform mean filtering on the two-dimensional position spectrum along the X direction and the Y direction using 1×3 and 3×1 templates.

[0044] Among them, in the above technical solution, steps 2 and 3 are to remove the singular points in the two-dimensional position spectrum, reduce the influence of statistical fluctuations on the original data, and avoid the situation of over-division when using the boundary division algorithm later. In step 3, mean filtering of the 1×3 and 3×1 templates is respectively performed on the two-dimensional position spectrum along the X direction and the Y direction to obtain the two-dimensional position spectrum 2X and the two-dimensional position spectrum 2Y. Then, the average of the same pixel positions of these two position spectra is taken to obtain the processed two-dimensional position spectrum, that is, the value of the pixel (X, Y) in the processed two-dimensional position spectrum = (two-dimensional position spectrum 2X(X, Y) + two-dimensional position spectrum 2Y(X, Y)) / 2.

[0045] Step 4: For the processed two-dimensional position spectrum, the center position estimation module 06 estimates the center position of each crystal bar using the local maximum algorithm for the two-dimensional position spectrum, and the binarization processor 15 performs binarization processing on the data, setting the pixel value of the brightest point to 1 and the remaining pixel values to 0, obtaining a binarized position spectrum diagram, as Figure 8 shown.

[0046] Among them, when the center position estimation module 06 performs one-dimensional peak searching on the processed two-dimensional position spectrum, the derivative peak searching method is used. One-dimensional peak searching is performed on the processed two-dimensional position spectrum along the X direction and the Y direction respectively. The pixel point value at the peak position is set to 1, and the pixel points at non-peak positions are set to 0. See Figure 6 and Figure 7 , Figure 6 is the peak searching result along the X direction; Figure 7 is the peak searching result along the Y direction. Then, for the peak searching results obtained along the X direction and the Y direction, the "AND operation" processor 14 performs an "AND operation" at the same pixel position. If the pixel point is a peak point along both the X direction and the Y direction, then the binarization processor 15 sets the pixel point value to 1, otherwise to 0. The binarization processing is completed. Finally, the center position of each crystal bar is estimated, as shown in Figure 8 shown.

[0047] Step 5: The distance calculation module 07 calculates the distance of each pixel point from the nearest bright point (the point with a pixel value of 1), obtaining a distance distribution diagram, as Figure 9 shown.

[0048] Among them, the Euclidean distance of each pixel point from the nearest bright point is calculated to obtain a distance distribution diagram. The calculated result is as shown in Figure 9 shown, only a part of which is shown. In the distance distribution diagram, the crystal bar boundary determination module 08 determines the boundary position corresponding to the crystal bar we need according to the local maximum.

[0049] Step 6: The one-dimensional peak searching unit 16 in the X direction and the one-dimensional peak searching unit 17 in the Y direction respectively perform local maximum searching on the distance distribution diagram along the X direction and the Y direction to determine the center position of the crystal bar and divide the boundaries of each crystal bar.

[0050] Among them, the local maximum algorithm is also used in this step 6. The specific steps are as follows:

[0051] The one-dimensional peak searching unit 16 in the X direction and the one-dimensional peak searching unit 17 in the Y direction perform one-dimensional peak searching on the distance distribution diagram along the X direction and the Y direction respectively using the derivative peak searching method;

[0052] The "OR operation" processor 18 performs an "OR operation" on the peak searching results in the X direction and the Y direction at the same pixel point, and the maximum value corresponds to the boundary position of each crystal bar, obtaining a boundary position distribution diagram, asFigure 10 as shown; meanwhile, calculate the crystal efficiency of each partition, such as Figure 11 shown

[0053] Step 7: Adopt the region identification algorithm to correspond each region to the crystal bar number one by one, and complete the mapping relationship between the scatter plot and the crystal bar

[0054] The specific steps are as follows

[0055] The region identification module 09 performs region identification on the boundary position distribution map. At this time, the formed region identification is not encoded in sequence. It only calculates which pixel points belong to the same region. The pixel points belonging to the same region adopt the same encoding, and the encoding between each region is ensured not to repeat

[0056] The boundary position obtained in the above Step 6 occupies one pixel, and it is necessary to judge which region this pixel point belongs to. The boundary attribution module 10 judges the boundary attribution according to the characteristics of the one-dimensional peak-seeking algorithm in Step 6 according to the following rules: The boundary points in the X direction belong to the region on the right, and the boundary points in the Y direction belong to the region below

[0057] The region sequence encoder 11 adopts the sequence encoding algorithm to make each region correspond to the crystal table encoding sequence, and complete the mapping relationship between the scatter plot and the crystal bar

[0058] And Step 8: The position mapping table generation module 12 adopts the boundary extraction position mapping algorithm to generate the position mapping table, as Figure 12 shown, only showing the partial position mapping table corresponding to the B region shown in Figure 10 Among them, it is required that the generated position mapping table should match the subsequent software interface, and the generated position mapping table is output from the system through the position mapping table output module 13

[0059] The present invention provides a method and system for generating a position mapping table of the interaction position between a crystal bar and a gamma photon. A point source or a general source is used to continuously map a crystal array, and the PMT received signal is calculated to obtain a scatter plot reflecting the interaction position of the coincidence event. After digital processing to remove the singular points in the two-dimensional position spectrum, the local maximum value algorithm is used for the two-dimensional position spectrum to estimate the center position of each crystal bar, and the data is binarized to obtain a binarized position spectrum map; the Euclidean distance from each pixel point to the nearest bright point is calculated for the binarized position spectrum map to obtain a distance distribution map; the local maximum values are obtained for the distance distribution map along the X direction and the Y direction respectively, and the boundary positions of each crystal bar are divided. In this way, each region corresponds to the crystal bar array one by one, and then the position mapping table of the system is determined. This method can cover all positions and there will be no divided dead zones

[0060] For those skilled in the art, various corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all such changes and deformations should fall within the protection scope of the claims of the present invention.

Claims

1. A method for generating a mapping table of the interaction position between a crystal bar and gamma photons, characterized in that: It includes the following steps: Step 1: Perform two-dimensional statistics on the position information of incident photon events to obtain a two-dimensional position spectrum, where the brightness of each pixel point in the two-dimensional position spectrum represents the number of events at that position; Step 2: Perform median filtering on the obtained two-dimensional position spectrum using a 3*3 two-dimensional template; Step 3: Perform mean filtering on the two-dimensional position spectrum along the X direction and Y direction respectively using 1*3 and 3*1 templates; Step 4: Use the local maximum algorithm to estimate the center position of each crystal bar for the two-dimensional position spectrum, and perform binarization processing on the data to obtain a binarized position map; Step 5: Calculate the Euclidean distance of each pixel point in the binarized position map from the nearest bright point to obtain a distance distribution map; Step 6: Find the local maximum along the X direction and Y direction respectively for the distance distribution map and divide the boundary positions of each crystal bar; Step 7: Adopt a region identification algorithm to correspond each region with the crystal bar number one by one to complete the mapping relationship between the scatter plot and the crystal bar; and Step 8: Adopt a boundary extraction position mapping algorithm to generate a position mapping table; Among them, the said Step 4 includes: Perform one-dimensional peak searching on the two-dimensional position spectrum in the X direction and Y direction respectively; Perform an "AND operation" on the peak searching results in the X direction and Y direction at the same pixel point. If the pixel point is a peak point in both the X direction and Y direction at the same time, then set the value of this pixel point to 1, otherwise set it to 0, and the binarization processing is completed; The said Step 6 includes: Adopt the derivative peak searching method to perform one-dimensional peak searching on the distance distribution map along the X direction and Y direction respectively; Perform an "OR operation" on the peak searching results in the X direction and Y direction at the same pixel point, and the position with the largest value corresponds to the boundary position of each crystal bar to obtain a boundary position distribution map; Among them: The said Step 7 includes: region identification, boundary attribution, and sequential coding; The said region identification includes: performing region identification on the boundary position distribution map, and the formed region identification is not encoded in sequence but randomly, only calculating which pixel points belong to the same region, and the pixel points belonging to the same region adopt the same coding, and the coding between each region is ensured not to repeat.

2. A method for generating a mapping table of the interaction position between a crystal bar and gamma photons according to claim 1, characterized in that: The said boundary attribution includes: When judging the region attribution of the pixel points corresponding to the boundary positions, according to the characteristics of the one-dimensional peak searching algorithm used in finding the local maximum of the distance distribution map, the boundary attribution judgment is carried out according to the following rules: The boundary points along the X direction belong to the region on the right side of the boundary, and the boundary points along the Y direction belong to the region below the boundary.

3. A method for generating a mapping table of the interaction position between a crystal bar and gamma photons according to claim 1, characterized in that: The said sequential coding includes adopting a sequential coding algorithm to make each region correspond to the crystal table coding sequence one by one to complete the mapping relationship between the scatter plot and the crystal bar.

4. A system for generating a mapping table of the interaction position between a crystal bar and gamma photons, characterized in that: The system includes: an array of crystals, a data statistics detector, a median filtering processor, an average filtering processor, a central position estimation module for crystal bars, a distance calculation module, a crystal bar boundary determination module, a region identification module, a boundary attribution module, a region sequence encoder, a position mapping table generation module, and a position mapping table output module. The array of crystals has multiple crystal bars. The data statistics detector is coupled to the array of crystals. The data statistics detector, the median filtering processor, the average filtering processor, the central position estimation module for crystal bars, the distance calculation module, the crystal bar boundary determination module, the region identification module, the boundary attribution module, the region sequence encoder, the position mapping table generation module, and the position mapping table output module are connected in sequence; Among them, both the median filtering processor and the average filtering processor are Gaussian filtering processors. The average filtering processor includes an average filtering processor in the X direction and an average filtering processor in the Y direction. Both the average filtering processor in the X direction and the average filtering processor in the Y direction are connected to the median filtering processor and the central position estimation module for crystal bars. The average filtering processor in the X direction is an average filtering processor with a 1*3 template, and the average filtering processor in the Y direction is an average filtering processor with a 3*1 template; The central position estimation module for crystal bars has an "AND operation" processor and a binarization processor. The "AND operation" processor and the binarization processor are integrated in series into the central position estimation module for crystal bars; The crystal bar boundary determination module includes a one-dimensional peak searching unit in the X direction, a one-dimensional peak searching unit in the Y direction, and an "OR operation" processor. The one-dimensional peak searching unit in the X direction, the one-dimensional peak searching unit in the Y direction, and the "OR operation" processor are integrated into the crystal bar boundary determination module. Both ends of the one-dimensional peak searching unit in the X direction and the one-dimensional peak searching unit in the Y direction are respectively connected to the distance calculation module and the "OR operation" processor. The other end of the "OR operation" processor is connected to the region identification module; The region identification module performs region identification on the boundary position distribution map. The formed region identification is not encoded in sequence but randomly. It only calculates which pixel points belong to the same region. Pixel points belonging to the same region use the same encoding, and the encoding between each region is guaranteed not to repeat.

5. A system for generating a position mapping table of the interaction between crystal bars and gamma photons as described in claim 4, characterized in that: The data statistics detector is a PET detector.

6. A system for generating a position mapping table of the interaction between crystal bars and gamma photons as described in claim 4, characterized in that: The median filtering processor is a median filtering processor with a 3*3 two-dimensional template.

7. A system for generating a position mapping table of the interaction between crystal bars and gamma photons as described in claim 4, characterized in that: The distance calculation module is an Euclidean distance calculator.

8. A system for generating a position mapping table of the interaction between crystal bars and gamma photons as described in claim 4, characterized in that: The encoder of the region identification module is a random encoder.

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