A gamma pair imaging tomograph based on optical communication and a data acquisition method thereof

Abstract

The application discloses a gamma pair imaging tomograph based on optical communication and a data acquisition method thereof, wherein the gamma pair imaging tomograph comprises a detector module, a local area network cabinet module and an image workstation. The method comprises the following steps: a scintillation crystal module generates visible light, and a photomultiplier tube converts the light pulse signal into an electric pulse signal; an analog-to-digital converter shapes and amplifies the electric pulse signal; a coincidence processing board performs time coincidence on the digitized pulse time signal; information of the coincidence event is transmitted to the image workstation; a host computer program can separate time and position information from the data packet, extract features of the information at the same time, and output binary files of time spectrum and position spectrum. The application can improve the precision of the imaging tomograph, reduce the cost, improve the imaging efficiency, improve the reliability and expandability of the equipment and the like.

Description

Technical Field

[0001] This invention relates to the fields of signal transmission technology, radiation detection, and medical imaging, and more specifically to a gamma-pair imaging tomography instrument based on optical communication and its data acquisition method. Background Technology

[0002] Gamma-ray pair imaging is a tomographic imaging system that can visualize human functional activities. Many diseases can be detected by tomographic imaging before changes occur in anatomical images, thus becoming an indispensable detection method in the medical field. A complete gamma-ray pair imaging tomography system generally includes the following three parts: a tracer synthesis device, a gamma-ray pair imaging tomography instrument, and an image processing server. Radioactive nuclides are synthesized with compounds needed for human metabolism, such as glucose, choline, and acetic acid, to form tracers. After being injected into the human body, these tracers emit positrons and neutrinos. These positrons interact with other electrons in human tissues, annihilating each other and emitting two pairs of gamma photons with opposite directions and equal energy (511 keV). Because different tissues in the body have different glucose uptake rates—specifically, different diseased tissues, such as malignant tumors, have a higher metabolic rate than normal tissues, and therefore a relatively higher tracer content—by detecting coincidences of these gamma photon pairs and reconstructing the location distribution of the annihilation events, early detection and localization of diseased tissues can be achieved.

[0003] Gamma-ray imaging tomography mainly consists of two parts: a detector module and a gamma-ray pair acquisition and processing module. The detector module detects scintillation pulse signals and converts them into analog electrical signals, while the gamma-ray pair acquisition and processing section extracts event information from the analog electrical signals.

[0004] The imaging quality of a fully digital imaging tomography instrument is closely related to its temporal resolution. Commercially available traditional time measurement methods suffer from problems such as low measurement accuracy or excessive cost. Summary of the Invention

[0005] The purpose of this invention is to provide a gamma-pair imaging tomography instrument based on optical communication and its data acquisition method. This instrument and method have the characteristics of rapid imaging, high sensitivity and non-invasiveness. It can effectively receive signals in vitro and then form images, which can show the condition inside organs or tissues.

[0006] A gamma-pair imaging tomography system based on optical communication includes a scintillation crystal module.

[0007] The basic detector module is used to absorb gamma rays and emit ultraviolet and visible light, and convert the optical signal into an electrical signal, which is connected to the coincidence processing section;

[0008] The conformance processing section is used to reconstruct the point source by measuring the point source using a time stamping method and determine the point source location. The conformance processing section is connected to the frame encapsulation module.

[0009] The frame encapsulation module is used to match and encapsulate the obtained position information, energy information, and time information, and connect it to a network module.

[0010] An intelligent dual-time clock module is used to provide a counting clock, and the intelligent dual-time clock module is connected to a time signal collection module;

[0011] The time signal aggregation module is used to calculate the time value of the rising edge of each logic pulse under the master clock source. The time signal aggregation module is connected to the intelligent dual-time clock module.

[0012] Furthermore, the basic detector module includes a scintillation crystal module and a quantum optoelectronic module, wherein the scintillation crystal module is used to receive gamma rays and emit visible light, and the quantum optoelectronic module is used to convert optical signals into electrical signals.

[0013] Furthermore, the scintillation crystal module includes several scintillation crystals, which are single crystals of an oxygen-containing rare earth compound.

[0014] Furthermore, the intelligent dual-time clock module includes three levels of time precision. The first clock provides a first-level time count T1 to the time-to-digital converter, and the second clock provides a second-level time count T2 with higher precision to the time-to-digital converter. It is a further subdivision of the first-level time count. At the same time, a third level of time precision is adopted, denoted as the third-level time count T3, which can determine whether to use the count value of the first half cycle or the second half cycle based on the results of the time measurements of T1 and T2.

[0015] Furthermore, the secondary and tertiary time counting are implemented using the FPGA's dedicated carry chain.

[0016] Furthermore, the primary clock count value is matched with the secondary clock count value to obtain the time information of the rising edge of the same pulse; the acquired time information is then collected in the time signal aggregation module.

[0017] Furthermore, when annihilation occurs, a coincident event is considered to be data with an energy close to 511 keV that is captured within a time window by a set of basic detector modules at 180-degree angles to each other.

[0018] Furthermore, the scanning plane formed by multiple basic detector modules is divided into four quadrants. An event will receive information in two quadrants, which can form six combinations, thereby filtering out invalid data outside the imaging field of view. At the same time, electronic collimation is achieved by relying on the special direction of photons and the coincidence circuit to filter out random coincidence and scattering coincidence events.

[0019] Furthermore, the crystal bar number, energy signal, and arrival time of the gamma photon hit in the event are encapsulated in the form of list data and transmitted to the network module.

[0020] In order to achieve the objectives of this invention, the following technical solution is also provided:

[0021] A method for acquiring data from an imaging tomography system based on optical communication includes:

[0022] Step S1: The scintillation crystal module is excited after absorbing gamma photons and can generate visible light;

[0023] Step S2: The photomultiplier tube converts the optical pulse signal into an electrical pulse signal and transmits the electrical pulse signal to the local area network chassis;

[0024] Step S3: The analog-to-digital converter shapes and amplifies the electrical pulse signal, and converts it into a digital time pulse signal through the time-to-digital converter module. The frame encapsulation module encapsulates the pulse energy, time, position and basic detector module number information of the flickering event and sends it to the compatibility processing board.

[0025] Step S4: The coincidence processing board performs time coincidence on the digitized pulse time signal. If the detector detects two photons that are 180 degrees apart within the specified time window, it is considered as a coincidence event.

[0026] Step S5: Transmit the information matching the event to the image workstation in the form of list data via the server;

[0027] Step S6: The host computer program can separate the time and location information from the data packet, and at the same time extract the features of the information, and output binary files of time spectrum and location spectrum.

[0028] Furthermore, the time matching process employs three levels of time precision, which effectively improves the time resolution while reducing the requirements for the precision and frequency of the master clock source, thereby reducing hardware costs.

[0029] Furthermore, the conformance processing section divides the scanning plane into four quadrants, such as... Figure 7 As shown, invalid data caused by the field of view (FOV) is filtered out, thereby improving the overall system efficiency.

[0030] Furthermore, the radioactive isotope may be 11C, 13N, 15O, 18F, 64Cu, etc.

[0031] Furthermore, the timing pulse can be set to be triggered by either the rising edge or the falling edge.

[0032] Furthermore, the reconstruction algorithm can use either an analytical reconstruction algorithm or an iterative reconstruction algorithm. Furthermore, the crystal array can be a crystal-clear LYSO crystal.

[0033] This invention can improve the accuracy of imaging tomography, reduce costs, improve imaging efficiency, and enhance equipment reliability and scalability. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0035] Figure 1 This is a block diagram illustrating the principle of a gamma-ray imaging tomography system.

[0036] Figure 2 This is a schematic diagram of the structure of the chromatography apparatus provided in the embodiments of this application;

[0037] Figure 3 This is a schematic diagram of the first quadrant gamma pair acquisition and processing module.

[0038] Figure 4 This is a schematic diagram of the intelligent dual-time clock module;

[0039] Figure 5 The position spectrum was obtained by this chromatography instrument;

[0040] Figure 6 The time spectrum was measured using this chromatography instrument;

[0041] Figure 7 This is a schematic diagram of the four-quadrant coincidence method used in this chromatography instrument; Detailed Implementation

[0042] This invention provides a digital, modular, and standardized instrument.

[0043] Digital design refers to the full and effective use of digital circuits and various digital signal processing technologies to directly digitally sample the scintillation pulse signals acquired by the detector unit, including the time, position, energy, and reaction depth information of a single event. This effectively improves the flexibility of subsequent processing and enhances scalability.

[0044] Modular design means that this invention consists of multiple modules, each with a unique function. These modules are combined as follows to form a whole, fulfilling the required functions of the entire system. Modularity facilitates expansion and is beneficial for system maintenance, debugging, and updates.

[0045] Standardized design means that the system is based on standardized hardware and software interface design, which is conducive to forming a complete open platform. Specifically, this invention provides a gamma-pair imaging tomography instrument based on optical communication and its data acquisition method. The instrument and method have the characteristics of rapid imaging, high sensitivity, and non-invasiveness. It can effectively receive signals in vitro and then form images, which can show the condition inside organs or tissues.

[0046] The optical communication-based gamma-pair imaging tomography system includes a scintillation crystal module.

[0047] The basic detector module is used to absorb gamma rays and emit ultraviolet and visible light, and convert the optical signal into an electrical signal, which is connected to the coincidence processing section;

[0048] The conformance processing section is used to reconstruct the point source by measuring the point source using a time stamping method and determine the point source location. The conformance processing section is connected to the frame encapsulation module.

[0049] The frame encapsulation module is used to match and encapsulate the obtained position information, energy information, and time information, and connect it to a network module.

[0050] The intelligent dual-time clock module is used to provide a counting clock, and the intelligent dual-time clock module is connected to the time signal collection module; the time signal collection module is used to calculate the time value of the rising edge of each logic pulse under the master clock source, and the time signal collection module is connected to the intelligent dual-time clock module.

[0051] Furthermore, the basic detector module includes a scintillation crystal module and a quantum optoelectronic module, wherein the scintillation crystal module is used to receive gamma rays and emit visible light, and the quantum optoelectronic module is used to convert optical signals into electrical signals.

[0052] Furthermore, the scintillation crystal module includes several scintillation crystals, which are single crystals of an oxygen-containing rare earth compound.

[0053] Furthermore, the intelligent dual-time clock module includes three levels of time precision. The first clock provides a first-level time count T1 to the time-to-digital converter, and the second clock provides a second-level time count T2 with higher precision to the time-to-digital converter. It is a further subdivision of the first-level time count. At the same time, a third level of time precision is adopted, denoted as the third-level time count T3, which can determine whether to use the count value of the first half cycle or the second half cycle based on the results of the time measurements of T1 and T2.

[0054] Furthermore, the secondary and tertiary time counting are implemented using the FPGA's dedicated carry chain.

[0055] Furthermore, the primary clock count value is matched with the secondary clock count value to obtain the time information of the rising edge of the same pulse; the acquired time information is then collected in the time signal aggregation module.

[0056] Furthermore, when annihilation occurs, a coincident event is considered to be data with an energy close to 511 keV that is captured within a time window by a set of basic detector modules at 180-degree angles to each other.

[0057] Furthermore, the scanning plane formed by multiple basic detector modules is divided into four quadrants. An event will receive information in two quadrants, which can form six combinations, thereby filtering out invalid data outside the imaging field of view. At the same time, electronic collimation is achieved by relying on the special direction of photons and the coincidence circuit to filter out random coincidence and scattering coincidence events.

[0058] Furthermore, the crystal bar number, energy signal, and arrival time of the gamma photon hit in the event are encapsulated in the form of list data and transmitted to the network module.

[0059] The method for acquiring data from an optical communication-based gamma-ray imaging tomography system includes:

[0060] Step S1: The scintillation crystal module is excited after absorbing gamma photons and can generate visible light;

[0061] Step S2: The photomultiplier tube converts the optical pulse signal into an electrical pulse signal and transmits the electrical pulse signal to the local area network chassis;

[0062] Step S3: The analog-to-digital converter shapes and amplifies the electrical pulse signal, and converts it into a digital time pulse signal through the time-to-digital converter module. The frame encapsulation module encapsulates the pulse energy, time, position and basic detector module number information of the flickering event and sends it to the compatibility processing board.

[0063] Step S4: The coincidence processing board performs time coincidence on the digitized pulse time signal. If the detector detects two photons that are 180 degrees apart within the specified time window, it is considered as a coincidence event.

[0064] Step S5: Transmit the information matching the event to the image workstation in the form of list data via the server;

[0065] Step S6: The host computer program can separate the time and location information from the data packet, and simultaneously extract the features of the information, outputting binary files of the time spectrum and location spectrum. Furthermore, the time synchronization process employs three levels of time precision, which effectively improves the time resolution while reducing the requirements for the accuracy and frequency of the master clock source, thereby reducing hardware costs.

[0066] Furthermore, the conformance processing section divides the scanning plane into four quadrants, such as... Figure 7 As shown, invalid data caused by the field of view (FOV) is filtered out, thereby improving the overall system efficiency.

[0067] Furthermore, the radioactive isotope may be 11C, 13N, 15O, 18F, 64Cu, etc.

[0068] Furthermore, the timing pulse can be set to be triggered by either the rising edge or the falling edge.

[0069] Furthermore, the reconstruction algorithm can be either an analytical reconstruction algorithm or an iterative reconstruction algorithm.

[0070] Furthermore, the crystal array can be made of crystal-clear LYSO crystals.

[0071] This invention can improve the accuracy of imaging tomography, reduce costs, increase imaging efficiency, and enhance equipment reliability and scalability. The invention is further illustrated below with specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0072] Figure 2 This is a schematic diagram of a gamma-ray pair tomography instrument based on optical communication according to the present invention.

[0073] The gamma-ray imaging tomography system in this device mainly consists of three parts: a detector group 100, a local area network (LAN) chassis 200, a server 300, and an image workstation 400. The detector group 100 is directly connected to the LAN chassis 200. The detector group 100 receives gamma photons and converts them into electrical signals within the unit, which are then sent to the LAN chassis 200. The LAN chassis 200 processes the data to obtain the location, energy, and time information of the corresponding event, which is then transmitted to the server 300 via fiber optic communication. The server 300 then transmits the information to the image workstation 400 via fiber optic communication for image reconstruction.

[0074] The detector group 100 includes four detector modules 110, 120, 130, and 140, each group containing multiple detector modules such as 111, 112, etc., with identical structure and function. Each independent detector module is connected to its corresponding gamma pair acquisition and processing modules 211, 212, etc. A photomultiplier tube 111B is used to convert optical pulse signals into electrical pulse signals, which are then output to the corresponding gamma pair acquisition and processing module 211.

[0075] It should be noted that the independent detector module 111 has the same structure and function as the independent detector modules 112, 113... and corresponds one-to-one with the gamma pair acquisition and processing modules 211, 212...

[0076] The local area network (LAN) chassis 200 includes four sets of gamma pair acquisition and processing modules, corresponding to four quadrants: a first quadrant gamma pair acquisition and processing module 210, a second quadrant gamma pair acquisition and processing module 220, a third quadrant gamma pair acquisition and processing module 230, and a fourth quadrant gamma pair acquisition and processing module 240. These modules receive electrical pulse signals from detector module groups located in their respective quadrants. For example, the first quadrant gamma pair acquisition and processing module 210 corresponds to the first detector module group 110, and further, its internal detector module 111 corresponds to the gamma pair acquisition and processing module 211. It also includes a global clock module 250 and a convergence processing board 260.

[0077] The device of the gamma acquisition and processing module 211 is used to process the collected digital signals, extract parameters, correct energy, merge and sort single event information frames, and send them to the conformal processing board 260.

[0078] The local area network chassis 200 is used to process the electrical pulse signals collected by the detector group 100, reconstruct the measurement points using the time stamping method, and determine the location of the point source.

[0079] Among them, such as Figure 3 The first quadrant gamma pair acquisition and processing module 210 includes an analog-to-digital converter (ADC module) 211A, a time-to-digital converter (TDC module) 211B, a frame encapsulation module 211C, and a network module 211D; its structure is the same as that of the second quadrant gamma pair acquisition and processing module 220, the third quadrant gamma pair acquisition and processing module 230, and the fourth quadrant gamma pair acquisition and processing module 240.

[0080] The ADC module 211A is used to shape and amplify the electrical pulse signal and perform digital sampling. The sampling result is sent to the TDC module 211B.

[0081] The TDC module 211B is used to obtain the timing information of the electrical pulse signal generated by the photomultiplier tube, and the timing information data is sent to the frame generation module 211C.

[0082] The frame generation module 211C is used to encapsulate the pulse energy, time, and location information of the event and send it to the network module 211D;

[0083] The network module 211D is used for network data transmission and is connected to the conformal processing board 260 to send the packetized data frame to the conformal processing board 260.

[0084] The conformity processing board 260 is used to determine conformity events; the conformity event information that passes the conformity determination will be sent to the server 300.

[0085] Among them, such as Figure 4 The intelligent dual-time clock module 250 provides a global clock and global reset signal to the basic detector module. It includes an FPGA main controller 250A, a clock fan-out buffer 250B, a dedicated connector 250C, a network module 250E, and a memory 250D. It connects to each gamma pair acquisition and processing module via the dedicated connector 250C.

[0086] Server 300 is connected to the local area network (LAN) chassis 200 and serves as the medium for data communication between the LAN chassis 200 and the image workstation. Event information that passes the conditional judgment is sent to the image workstation.

[0087] Figure 4 This is a schematic diagram of the structure of an intelligent dual-time clock module for a gamma-to-tomograph based on optical communication according to the present invention.

[0088] In the past, clock distribution modules typically used FPGAs to directly output clock signals. This method often resulted in random jitter of 100ps-200ps. However, fully digital gamma-ray imaging tomography requires clock signals with jitter no greater than 10ps. Therefore, clock signals implemented using FPGAs cannot meet the requirements of fully digital gamma-ray imaging tomography.

[0089] Furthermore, this design employs an intelligent dual-time clock module. First, high-precision clock chips are cascaded to increase clock signal fan-out, thus meeting the requirements of multiple clock paths. Then, an FPGA chip is used to adjust the phase of the high-frequency clock, which can well meet the clock allocation requirements of a fully digital signal processing system.

[0090] Furthermore, the data processing section uses an FPGA chip as the processing chip and employs a three-level clock counting to achieve high-precision TDC functionality, which not only meets the processing and bandwidth requirements of large data volumes but also reduces costs.

[0091] Furthermore, the network module uses fiber optic communication for transmission, employs a time-sensitive network (TSN) communication method, and maintains backward compatibility with traditional Ethernet.

[0092] Furthermore, the intelligent dual-time clock module 250 provides the necessary clock source to the FPGA master controller 250A through a high-precision crystal oscillator 250F. The FPGA master controller 250A initializes the configuration file by connecting a memory 250D. The clock is generated using a PLL (phase-locked loop) integrated on the FPGA master controller 250A to generate a clock signal. The high-precision clock signal is then transmitted to the clock fan-out buffer 250B, which distributes multiple high-precision clock signals. At the same time, the FPGA master controller 250A generates a programmable reset signal. The synchronous clock signal and reset signal are output differentially through a dedicated connector 250C. The network module 250E is mainly used for writing the configuration file.

[0093] Furthermore, this design employs a three-level time accuracy. The first-level time counter T1 provides a counting clock with a relatively large period for the flash pulses, directly counting using the clock cycle. While this method offers a large range, its accuracy is poor. Therefore, a second-level time counter T2 is introduced. This clock utilizes time interpolation. By further dividing the resolution measured by T1 into n equal parts, if the time interval measured by the first-level time counter is t, then the interpolated time interval is t / n, effectively increasing the resolution of the measured time interval by n times. The final time interval can be obtained by multiplying the interpolated count by the interpolated time interval and adding the interval measured by the first-level clock. Combining the second-level and first-level time counters and performing final analysis yields a very accurate measurement of the time interval. This measurement value is determined by the carry chain delay, which can be as low as tens of ps. Furthermore, a third-level time counter T3 is introduced, which determines whether to use the count value of the first or second half of the cycle based on the results of the time measurements of T1 and T2, thus obtaining a more stable time measurement result.

[0094] An embodiment of the present invention for data acquisition of a gamma-ray tomography instrument based on optical communication includes the following steps:

[0095] Step S1: The scintillation crystal module 111A is excited after absorbing gamma photons and can generate visible light;

[0096] Step S2: The photomultiplier tube 111B converts the optical pulse signal into an electrical pulse signal and transmits the electrical pulse signal to the local area network chassis 200;

[0097] Step S3: The ADC module 211A shapes and amplifies the electrical pulse signal, and converts it into a digital time pulse signal through the TDC module 211B. The frame encapsulation module 211C encapsulates the pulse energy, time, position and basic detector module (BDM) number information of the flickering event, and sends it to the conformal processing board 260 through the network module 211D.

[0098] Step S4: The coincidence processing board 260 performs time coincidence on the digitized pulse time signal. If the detector detects two photons that are 180 degrees apart within the specified time window (0-15ns), it is considered as a coincidence event.

[0099] Step S5: Transmit the information matching the event to the image workstation 400 in list mode via server 300;

[0100] Step S6: The host computer program can separate the time and position information from the UDP packet, and simultaneously extract the features of the information, outputting binary files of the time spectrum and position spectrum: The position spectrum is a map drawn from the position information of photons hitting the detector. Because UDP data can reflect the position of photons, and by summing according to the X and Y coordinates, the final grayscale map of photon position distribution can be obtained, and the spatial resolution of the array crystal can be evaluated. For the time spectrum, the reference point of the scintillation pulse defines the alignment method of the scintillation pulse. The aligned pulse can clearly obtain the statistical characteristics of the rapidly changing rising edge. The reference point of the pulse defines the arrival time of the scintillation event, and thus the time spectrum can be given.

[0101] In the above steps, the intelligent dual-time clock module 250 is responsible for providing various clock signals required for the operation of the entire system. In step S3, a three-level time precision counting method is adopted; if an annihilation event occurs, two flashing events are obtained, each containing position information P, E, T1, T2 and P', E', T1, T2', and time information T1, T3. The frame encapsulation module encapsulates P', E, E', T1, T2, T2', T3 and sends them to the conformal processing board.

[0102] In step S4 above, the coincidence processing part divides the detector group 100 into 4 quadrants. There are C42 combinations in the coincidence judgment stage. The obtained pulses are then ANDed. Events detected in the same quadrant are not internally coincident. This can filter out invalid data outside the FOV. At the same time, electronic collimation is achieved by relying on the special direction of photons and the coincidence circuit to filter out random coincidence and scattering coincidence events.

[0103] In step S5 above, the communication between the local area network chassis 200 and the server 300, and between the server 300 and the image workstation 400, adopts fiber optic communication.

[0104] Furthermore, in the description of this application, the terms "first," "second," "third," etc., are used only for descriptive purposes and to distinguish similar objects; there is no order of precedence between them, nor should they be construed as indicating or implying relative importance. In addition, in the description of this application, unless otherwise stated, "multiple" means two or more.

[0105] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims of this patent. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A gamma pair imaging tomograph based on optical communication, characterized in that, It includes scintillation crystal module, basic detector module, which is used for absorbing gamma rays and emitting ultraviolet and visible light, and converting light signal into electric signal, and connecting with coincidence processing part; coincidence processing part, which is used for measuring point source by time mark method, reconstructing, and determining point source position, and connecting with frame packaging module; frame packaging module, which is used for matching and packaging position information, energy information, and time information, and connecting with network module; intelligent double time part clock module, which is used for providing counting clock, and connecting with time signal collection module; time signal collection module, which is used for calculating time value of each logic pulse rising edge under main clock source, and connecting with intelligent double time part clock module; The basic detector module comprises a scintillation crystal module and a quantum photoelectric module, wherein the scintillation crystal module is used for receiving gamma rays and emitting visible light, and the quantum photoelectric module is used for converting light signals into electric signals. The intelligent double time part clock module comprises three levels of time precision, a first clock provides a first level of time count T1 for a time-to-digital converter, a second clock provides a second level of time count T2 with higher precision for the time-to-digital converter, and the second level of time count T2 is a subdivision of the first level of time count; meanwhile, a third level of time count T3 is adopted, and the third level of time count T3 can determine whether to use the count value of the first half period or the count value of the second half period according to the measurement results of T1 and T2. The second level of time count and the third level of time count are realized by using a special carry chain of FPGA.

2. The optical communication based gamma pair imaging tomograph according to claim 1, characterized in that, The scintillation crystal module comprises a plurality of scintillation crystals, and the scintillation crystals adopt a single crystal of an oxygen-containing rare earth compound.

3. The optical communication based gamma pair imaging tomograph of claim 1, wherein, The first level of clock count value and the second level of clock count value are matched to obtain time information of the rising edge of the same pulse; and the obtained time information is collected in the time signal collection module.

4. The optical communication based gamma pair imaging tomograph of claim 1, wherein, When annihilation occurs, only the data captured by a group of basic detector modules which are 180 degrees apart, within a time window, and with energy close to 511 keV are considered as a coincidence event.

5. The optical communication based gamma pair imaging tomograph of claim 1, wherein, The scanning plane surrounded by a plurality of basic detector modules is divided into four quadrants, and a single event can receive information in two quadrants, so that six combination modes can be formed to filter out invalid data outside the imaging field of view; meanwhile, electronic collimation is realized by relying on the special direction of photons and coincidence circuit to filter out random coincidence and scattering coincidence events.

6. The optical communication based gamma pair imaging tomograph of claim 1, wherein, The crystal bar number, energy signal and arrival time of the gamma photons in the coincidence event are packaged in the form of list type data and transmitted to the network module.

7. A data acquisition method of a gamma pair imaging tomograph based on optical communication according to any one of claims 1-6, comprising the following steps: S1: a scintillation crystal module is excited after absorbing gamma photons and can generate visible light; S2: a photomultiplier tube converts the light pulse signal into an electric pulse signal and transmits the electric pulse signal to a local area network cabinet; S3: an analog-to-digital converter shapes and amplifies the electric pulse signal, and converts the electric pulse signal into a digital time pulse signal through a time-to-digital converter module, a frame packaging module packages the pulse energy, time, position and basic detector module number information of the pulse signal, and sends the pulse signal to a coincidence processing board; S4: the coincidence processing board performs time coincidence on the digital pulse time signal, and if two photons that are 180 degrees apart are detected by a detector within a specified time window, the two photons are considered as a coincidence event; S5: the information of the coincidence event is uploaded to an image workstation in the form of list-type data through a server; and S6: a host computer program can separate the time and position information from the data packet, extract the features of the information, and output a binary file of a time spectrum and a position spectrum.

Images