Fully simulated nuclide distribution imaging method and system

Abstract

A fully analog nuclide distribution imaging method and system, which includes a front-end signal detection module, which includes a scintillation crystal array module and a silicon photomultiplier tube array module in any combination; a data preprocessing module that analyzes and distinguishes scintillation pulse event signals and converts the events into time, position, and energy events; an image reconstruction module that realizes full analog quantity processing of effective signal events, fully guarantees the integrity of the events, and uses a digitally controlled resistor circuit inversion module to simplify the actual large-scale matrix inversion process to solve the stability, existence and uniqueness of the solution; and a display module that converts and displays data. The main parts of the system are analog circuits, which reduces the electronic radiation interference of the instrument, and has lower cost and stronger practicality. The method is to set the parameters accordingly and use Kirchhoff's law to simply and conveniently realize image reconstruction.

Description

Technical Field

[0001] The present invention relates to the field of radiation detection imaging technology, and in particular to a full-simulation nuclide distribution imaging method and system. Background Art

[0002] Positron emission tomography (PET) and single photon emission computed tomography (SPECT) are both non-invasive imaging methods. Their basic principle is to use radioactive isotopes as tracers. When such tracers are injected into the human body, the radioactive nuclides will decay to produce antiparticles, namely positrons. When the positrons produced by the decay of the radioactive nuclides collide and annihilate with the negative electrons in the organism, the positron-negative electron pair disappears and produces a pair of γ photons with equal energy of 511 KeV and opposite movement directions. PET uses a ring-shaped position-sensitive radiation detector surrounding the organism to convert the incident γ photons into visible light signals, and then converts the light signals into electrical pulse signals, thereby obtaining their energy, position and time information. Through the annihilation coincidence technology, the position of the response line where the annihilation event is located is obtained, and the distribution of the radioactive nuclides in the organism is obtained through a two-dimensional or three-dimensional tomography reconstruction algorithm, so as to observe the physiological and biochemical processes in the organism in vitro.

[0003] Processing medical imaging data in PET and SPECT imaging systems is one of the most important links. It is a high-complexity, large data stream real-time computing task. Only by integrating the data and reconstructing the medical image can the image be seen intuitively, which is convenient for doctors to analyze the patient. Among them, matrix operations are the basic operators in modern medical image reconstruction processing, and their implementation results are the main factors affecting the overall performance of the system. The difficulty of matrix operations lies in matrix inversion. The matrix inversion calculation process is complex, the amount of calculation is large, the existence, uniqueness and stability of the solution are uncertain, and the real-time performance of the software implementation is poor, which seriously restricts the improvement of the system calculation speed.

[0004] In the prior art, the reconstruction of medical image data is mostly achieved through software, which requires the image to be discretized and segmented, and the solution to the original signal is a fuzzy solution and an approximate solution. In addition, its calculation speed is very slow and its efficiency is very low. In many cases, the commonly used image reconstruction algorithms are Filtered Backprojection (hereinafter referred to as FBP), Algebraic Reconstruction Technique (hereinafter referred to as ART) and Ordered Subsets Expectation Maximization (hereinafter referred to as OSEM). Among them, the FBP algorithm is relatively fast but also takes dozens of minutes, but the effect is poor, while the reconstruction of ART and OSEM algorithms usually takes several hours, which is better than FBP. These algorithms require a high-speed server for calculation, which is costly, and either the time is difficult to meet the needs of practical applications, or the accuracy is difficult to meet the requirements of practical applications. With the development of science and technology, breakthroughs in hardware chips, etc., hardware-based medical image reconstruction systems have begun to be developed. For example, with the development of process technology and market needs, new FPGAs with ultra-large scale, high speed and low power consumption are constantly being introduced. Now the new generation of FPGA has more and more abundant internal resources, and new storage technologies are constantly emerging, providing powerful hardware support for the realization of FPGA medical image reconstruction system. Although its cost is lower than that of servers, it still uses ADC chips with ultra-high sampling rates, which is still very expensive, and can only get approximate solutions. The use of FPGA requires a clock signal, so its time performance is not superior, and due to the effect of electronic radiation, it will interfere with gamma rays and the authenticity of image data.

[0005] Therefore, in the face of the above technical problems, it is necessary to provide a full-simulation nuclide distribution imaging method and system to solve the above problems and defects. Summary of the invention

[0006] The purpose of the present invention is to provide a fully analog nuclide distribution imaging system and method to solve the problems of imaging time drift and fuzzy solution in high-energy physics particle detection and medical imaging equipment. The method uses a digitally controlled resistor hardware circuit to directly process analog signals, innovatively proposes a system and method using digitally controlled resistors and operational amplifiers to achieve a matrix inversion function, and uses Kirchhoff's theorem combined with the principle of virtual short and virtual break of operational amplifiers to achieve the problem of obtaining a natural and accurate solution to the matrix inversion.

[0007] In order to solve the above technical problems, the present invention provides a solution:

[0008] A full-simulation nuclide distribution imaging system, the system comprising:

[0009] A front-end signal detection module, comprising a scintillation crystal array module and a silicon photomultiplier tube array module, wherein the scintillation crystal array module and the silicon photomultiplier tube array module are connected via a light guide, and the front-end signal detection module converts detected gamma photons into scintillation pulse event signals;

[0010] The data preprocessing module includes:

[0011] A pulse signal analysis module, which converts the scintillation pulse event signal obtained by the front-end signal detection module into three types of information: time, energy and position;

[0012] The event discrimination module is connected with the pulse signal analysis module, and the time energy threshold of the response is set by the threshold comparator to convert it into a coincidence event.

[0013] An image reconstruction module, comprising:

[0014] A digitally controlled resistance circuit inversion module, wherein the digitally controlled resistance circuit inversion module is connected to the event discrimination module to perform image reconstruction on the information;

[0015] A parameter setting module, the parameter setting module is connected to the digital control resistance circuit inversion module to set the resistance value and the input voltage;

[0016] A signal measurement module is connected to the digitally controlled resistance circuit inversion module to measure the output signal.

[0017] The display module comprises:

[0018] A transmission module, wherein the transmission module is connected to a signal measurement module to transmit the signal in parallel to a host computer;

[0019] The conversion display module is connected to the signal detection module to convert the signal into a corresponding grayscale value and display it.

[0020] Furthermore, the scintillation crystal array module includes n*n scintillation crystals, and the silicon photomultiplier tube array module includes n*n SiPM silicon photomultiplier tubes.

[0021] Furthermore, the light guide is made of optical glass and is coupled between the scintillation crystal array and the silicon photomultiplier tube array by optical glue.

[0022] Furthermore, the data preprocessing module sets the threshold value by analyzing the prior information of the scintillation pulse event signal to obtain corresponding information.

[0023] Furthermore, the digitally controlled resistor circuit inversion module in the image reconstruction module uses a module combining a digitally controlled resistor and an operational amplifier to perform data processing and image reconstruction.

[0024] Furthermore, the digitally controlled resistance circuit inversion module adopts a resistance corresponding system response matrix and uses Kirchhoff's law to implement the inverse operation of the matrix to achieve the image reconstruction process.

[0025] Furthermore, the digitally controlled resistance circuit inversion module adopts a full analog signal processing method, and both the input and output are voltage signals.

[0026] Furthermore, the resistor in the digitally controlled resistor circuit inversion module is a high-precision digitally controlled resistor.

[0027] Furthermore, the signal measurement module adopts multi-channel real-time measurement.

[0028] Furthermore, the display module adopts a parallel transmission structure.

[0029] In order to solve the above technical problems, the present invention also provides a solution:

[0030] A method for fully simulating nuclide distribution imaging, characterized in that the method comprises the following steps:

[0031] Step S1: Determine the parameters of the front-end signal detection module according to user requirements.

[0032] Step S2: obtaining a scintillation pulse event signal obtained by converting a gamma photon received by a scintillation crystal in a front-end signal detection module through a photomultiplier tube;

[0033] Step S3: Analyze the signal obtained by the signal detection module to obtain biological image projection data P;

[0034] Step S4: according to the system geometry of the signal detection module, the system response matrix H is obtained by Monte Carlo simulation or analytical method, and the number of parameters in the matrix is ​​determined by looping through the matrix;

[0035] Step S5: setting the resistance parameter of the corresponding digitally controlled resistor according to the size of each element in the system response matrix H;

[0036] Step S6: setting the input voltage of the digitally controlled resistor circuit according to the size of each element in the projection data P, and then measuring the output voltage;

[0037] Step S7: convert the output voltage signal into data and display it.

[0038] Furthermore, in the above step S1, the parameters of the detection module are variable.

[0039] Furthermore, the projection data obtained in the above step S3 are all non-negative.

[0040] Furthermore, in the above step S4, the system response matrix is ​​fixed, which is determined by the system geometry of the signal detection module.

[0041] Furthermore, in the above step S4, the system geometry is an annular regular polygon.

[0042] Furthermore, in the above step S5, the resistance parameters of the set digitally controlled resistor are determined, and a fixed signal detection module corresponds to the fixed parameters.

[0043] Furthermore, in the above step S5, both the input and output signals are analog signals.

[0044] Furthermore, in the above step S6, the output voltage is measured by multi-channel simultaneous measurement.

[0045] Furthermore, in the above step S7, the data transmission conversion is performed in parallel.

[0046] Furthermore, in the above step S7, the voltage signal is converted into corresponding pixel values ​​in a one-to-one correspondence.

[0047] It can be seen from the technical solution provided by the present application that the present invention realizes medical image reconstruction by utilizing hardware, and innovatively uses digitally controlled resistors and operational amplifiers to realize the matrix inversion function, making full use of the characteristics of analog signals to ensure the integrity of the signal. Due to the different dimensions, matrix operations may bring a large amount of computation, and it is difficult to solve the inverse of the system response matrix, which are all approximate solutions. The realization of matrix inversion by digitally controlled resistors and operational amplifiers is a natural precise solution. Hardware implementation can give full play to the speed advantage of hardware, has accurate timing information, has a natural parallel flight speed, superior event performance, low power consumption, and the solution used is a combination of digitally controlled resistors and operational amplifiers, with low electronic radiation, low interference, and lower cost than single-chip microcomputers or FPGAs. It is of great significance for image reconstruction of medical imaging systems such as PET and SPECT. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings related to the present invention in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0049] Figure 1 This is the overall module structure diagram of the full simulation nuclide distribution imaging system.

[0050] Figure 2 Basic flow chart for matrix inversion of digitally controlled resistors.

[0051] Figure 3 Schematic diagram of the structure of a full-simulation nuclide distribution imaging system according to an embodiment of the present invention.

[0052] Figure 4 A schematic diagram of the structure for matrix inversion of a digitally controlled resistor.

[0053] Figure 5 This is the original data brain map of Shepp-Logan.

[0054] Figure 6 Sine diagram of the system measurement data. DETAILED DESCRIPTION

[0055] The present invention discloses a fully analog nuclide distribution imaging method and system, which is used to solve the problems of matrix inversion, imaging time drift and fuzzy solution in the field of high-energy physics particle detection and medical image reconstruction in medical imaging equipment. The method uses hardware circuits to directly process analog signals, innovatively proposes a system and method for using digitally controlled resistors and operational amplifiers to achieve matrix inversion functions, and uses Kirchhoff's theorem combined with the principle of virtual short and virtual break of operational amplifiers to achieve the purpose of obtaining a natural and accurate solution for matrix inversion.

[0056] The technical solutions in the embodiments of the present invention will be described in detail below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] Figure 3 FIG. 1 is a schematic diagram of the structure of a full simulation nuclide distribution imaging system according to an embodiment of the present invention. Figure 3 It can be seen that the full analog nuclide distribution imaging system in the present invention includes a front-end signal detection module 100, a data preprocessing module 200, an image reconstruction module 300, and a display module 400. As shown in the figure, there is a rectangular object to be measured. The object information is collected by the front-end signal detector module and then connected to the data preprocessing module for further processing to obtain projection data. The data preprocessing module 200 in the figure shows the obtained projection data, which is then connected to the image reconstruction module. The image reconstruction model is composed of a series of analog circuits, the core of which is to realize data reconstruction through a matrix inversion circuit of a digitally controlled resistor, and finally connected to the display module, so that the original appearance of the original object is also a rectangular object.

[0058] The full simulation nuclide distribution imaging system of the present invention is described in detail below.

[0059] A full analog nuclide distribution imaging system includes a front-end signal detection module 100, a data preprocessing module 200, and an image reconstruction module 300, wherein:

[0060] The front-end signal detection module 100 includes a scintillation crystal array module 110 and a silicon photomultiplier tube array module 120;

[0061] The data preprocessing module 200 includes a pulse signal analysis module 210 and an event identification module 220, wherein the pulse signal analysis module 210 is connected to the output end of the SiPM silicon photomultiplier tube array module 120 in the front-end signal detection module 100;

[0062] The image reconstruction module 300 includes a digitally controlled resistance inversion module 310, a parameter setting module 311, an operational amplifier circuit module 312, and a signal measurement module 320;

[0063] The display module 400 includes a data transmission module 410 and a conversion display module 420 .

[0064] Furthermore, the front-end signal detection module 100 collects gamma photon data. It receives gamma photons through the scintillation crystal array module 110, and then connects to the silicon photomultiplier tube array module 120 through an optical conductor to amplify the data signal and convert it into a pulse electrical signal, namely a scintillation pulse event signal.

[0065] Furthermore, the scintillation crystal array module 110 includes n*n scintillation crystals, and the silicon photomultiplier tube array module 120 includes n*n silicon photomultiplier tubes.

[0066] Furthermore, the light guide is made of optical glass and is coupled between the scintillation crystal array and the silicon photomultiplier tube array by optical glue.

[0067] Furthermore, the pulse signal analysis module 210 analyzes the scintillation pulse event signal to obtain its energy, time, and position information, and then sets a time window and an energy window through the event identification module 220 to identify it as a conforming event signal.

[0068] Furthermore, the digitally controlled resistor circuit inversion module in the image reconstruction module uses a module combining a digitally controlled resistor and an operational amplifier to perform data processing and image reconstruction.

[0069] Furthermore, the digitally controlled resistance circuit inversion module adopts a resistance corresponding system response matrix and uses Kirchhoff's law to implement the inverse operation of the matrix to achieve the image reconstruction process.

[0070] Furthermore, the digitally controlled resistance circuit inversion module adopts a full analog signal processing method, and both the input and output are voltage signals.

[0071] Furthermore, the resistors in the digitally controlled resistor circuit inversion module are high-precision digitally controlled resistors, which enables accurate setting of parameters.

[0072] Furthermore, the signal measurement module adopts multi-channel real-time measurement.

[0073] Furthermore, the measured output voltage is transmitted in parallel to the host computer and then converted into a corresponding pixel value through voltage conversion and displayed as one voltage corresponding to one pixel value, such as 1 volt corresponding to a pixel value of 10.

[0074] Furthermore, the display module adopts a parallel transmission conversion display structure, which can realize real-time transmission and display of image results.

[0075] The present invention provides a method for fully simulating nuclide distribution imaging, the method comprising the following steps:

[0076] Step S1: Determine the parameters of the front-end signal detection module according to user requirements, determine the number of scintillation crystals and the number of photomultiplier tubes to build the front-end signal detection module;

[0077] Step S2: obtaining a scintillation pulse event signal obtained by converting a gamma photon received by a scintillation crystal in a front-end signal detection module through a photomultiplier tube;

[0078] Step S3: Analyze the signal obtained by the signal detection module to obtain biological image projection data P;

[0079] Step S4: according to the system geometry of the signal detection module, the system response matrix H is obtained by Monte Carlo simulation or analytical method, and the number of parameters in the matrix is ​​determined by looping through the matrix;

[0080] Step S5: setting the resistance parameter of the corresponding digitally controlled resistor according to the size of each element in the system response matrix H;

[0081] Step S6: setting the input voltage of the digitally controlled resistor circuit according to the size of each element in the projection data P, and then measuring the output voltage;

[0082] Step S7: convert the output voltage signal into data and display it.

[0083] Furthermore, the parameters of the detection module in the above step S1 can be changed according to user needs.

[0084] Furthermore, in the above step S2, the scintillation pulse event signal is an analog signal.

[0085] Furthermore, the projection data obtained in the above step S3 uses a hardware integration circuit to obtain energy, and therefore all of them are non-negative.

[0086] Furthermore, in the above step S4, the system response matrix is ​​fixed, which is determined by the system geometry of the signal detection module.

[0087] Furthermore, in the above step S4, the system geometry is a circular regular polygon, which realizes a 360-degree full-body circular scan.

[0088] Furthermore, in the above step S5, the resistance parameters of the set digitally controlled resistor are determined, and a fixed signal detection module corresponds to the fixed parameters.

[0089] Furthermore, in the above step S6, both the input and output signals are analog signals.

[0090] Furthermore, in the above step S6, the output voltage is measured by multi-channel simultaneous measurement.

[0091] Furthermore, in the above step S7, the output voltage signal is converted into a corresponding pixel value and displayed as a corresponding image.

[0092] Furthermore, in the above step S7, the data transmission conversion is parallel and the result can be displayed in real time.

[0093] The full simulation nuclide distribution imaging method of the present invention is described in detail below.

[0094] Figure 4 This is a schematic diagram of a structure of a matrix inversion of a digitally controlled resistor according to an embodiment of the present invention, and its specific implementation steps are as follows:

[0095] S1: Determine the parameters of the front-end signal detection module according to user needs, and determine the number of scintillation crystals and photomultiplier tubes to build the front-end signal detection module.

[0096] S2: Obtain the scintillation pulse event signal obtained by the gamma photons received by the scintillation crystal in the front-end signal detection module and converted by the photomultiplier tube.

[0097] S3: Analyze the signal obtained by the signal detection module to obtain biological image projection data P

[0098] More specifically, a hardware integration circuit is used to integrate the data of each scintillation pulse event signal to obtain the energy, which is:

[0099]

[0100] It is assumed that Si is the i-th scintillation pulse event signal received by the detector, and Ei is the energy of the i-th scintillation pulse event signal.

[0101] S4: according to the system geometry of the signal detection module, a system response matrix H is obtained by using Monte Carlo simulation or analytical method, and the number of parameters in the matrix is ​​determined by looping through the matrix;

[0102] More specifically, the system response matrix H is the probability of a γ photon being detected, and the matrix relationship is:

[0103] P=HX (2)

[0104] Where X represents the vector group of random variables of the total number of gamma photons emitted by pixels in all directions; P represents the number of gamma photons detected by each response line LOR, which is a random variable detected by the detector; H represents the system response matrix.

[0105] There are n response lines LOR, corresponding to n variables, that is, a linear system of n equations.

[0106]

[0107] Among them, a 11, a 12, a 13....a nm represents the probability that the mth pixel is detected by the nth response line, which is an element of the system response matrix H, x represents the grayscale value of the nth pixel, and bn represents the total number of gamma photons received by the pixel in the direction of the response line LOR.

[0108] S5: Set the resistance parameters of the corresponding digitally controlled resistors according to the size of each element in the system response matrix H, implement image reconstruction using hardware methods, set the value of the system response matrix A to the parameters of the digitally controlled resistors and feedback resistors connected in parallel on the operational amplifier input circuit in the hardware circuit, and set P to the output voltage signal of the operational amplifier.

[0109] The hardware inversion uses Kirchhoff's theorem combined with the principle of virtual short and virtual break of the operational amplifier to achieve the purpose of matrix inversion. Since the system response matrix is ​​a certain matrix, it is only necessary to determine the ratio of each parallel resistor to the feedback resistor. Then the obtained data is set as the output voltage, so that the original signal can be obtained by measuring the voltage at the input end. The feedback circuit expression is as follows:

[0110]

[0111] R1, R2, R3...Rn represent the input parallel resistance of the common-phase proportional amplifier circuit, V1, V2, V3...Vn represent the input voltage of the corresponding resistance of the common-phase proportional amplifier circuit, Rm represents the feedback resistance of the common-phase proportional amplifier circuit, and Vo represents the output voltage of the common-phase proportional amplifier circuit, where Vo is a negative voltage.

[0112] Further sorting out the standard expression is:

[0113]

[0114] in Corresponding to each item of the system response matrix.

[0115] S6: setting the input voltage of the digital controlled resistor circuit according to the size of each element in the projection data P, and then measuring the output voltage.

[0116] More specifically, the output terminal of the operational amplifier is set to a different voltage each time, and this voltage corresponds to each value of the above P parameter. The voltage to be measured is the input terminal voltage V1, V2, V3...Vn of the operational amplifier, which is the image data to be obtained.

[0117] According to one embodiment of the present invention, Figure 5 As shown, it is a Shepp-Logan brain map, which is the original image, which is divided into a matrix of size 256*256. Then the size of the original image F is a column vector of size 65536, and the resulting projection data P is as follows Figure 6 The figure shows a sinogram, which is a sine graph. Its discretization size is a 367*360 matrix, so the size of the converted column vector is 132120. The system response matrix H is 132120*65536. When the system response matrix H and the projection data P are known, the following can be used to calculate the system response matrix H: Figure 4 The original image F can be obtained by the process of inverting the digital controlled resistance.

[0118] One embodiment of the present invention is the application of SPECT. SPECT uses radioactive isotopes as tracers. The tracers are injected into the human body to concentrate on the organs to be tested, thereby making the organs become gamma-ray sources. The distribution of radioactivity in the organ tissue is recorded by a detector rotating around the human body in vitro. A set of data can be obtained by rotating the detector by one angle, and several sets of data can be obtained by rotating one circle. A series of tomographic plane images can be established based on these data. The computer reconstructs the image in a cross-sectional manner.

[0119] The detected data are single-photon gamma rays, which are the SPECT medical imaging data collected in the early stage.

[0120] SPECT medical imaging data can be reconstructed through direct back-projection to obtain the distribution of radionuclides in the human body. This process can be reconstructed through a digitally controlled resistor analog circuit based on the obtained projection data and the system response matrix.

[0121] For the projection relationship P = fH, when the projection data P and the system response matrix H are known, the final formula for obtaining f is as follows:

[0122] f=PH -1

[0123] Where H=[H1,H2,H3…H n ], P=[P1, P2, P3…Pn];

[0124] Where Hn=[H n1 , H n2 , H n3 …H nn ] T ;

[0125] Figure 4 The ratio of each input resistance to the feedback resistance obtained by substituting the input and output into the equation represents one [Hnm].

[0126] Depend on Figure 4 The voltage corresponding to the nuclide distribution can be obtained by measuring the input end of the operational amplifier through the inverse process, and the nuclide distribution image can be obtained after being sorted by the host computer.

[0127] Another embodiment of the present invention is computed tomography (CT). It uses X-rays to irradiate the human body. Since different tissues or organs in the human body have different densities and thicknesses, they produce different degrees of attenuation of X-rays, thereby forming a grayscale image comparison distribution map of different tissues or organs, and then judging the condition by the changes in the relative position, shape and size of the lesion. Because CT has computer-assisted calculations, it presents a tomographic section with high resolution.

[0128] The data obtained by CT is the absorption data of X-rays, but it is still a kind of projection data P. Then according to Figure 2 The CT image is obtained by the steps of

[0129] The present invention realizes medical image reconstruction by utilizing hardware, innovatively uses digitally controlled resistors and operational amplifiers to realize the matrix inversion function, fully utilizes the characteristics of analog signals, and ensures the integrity of signals. Due to different dimensions, matrix operations may bring a large amount of computation, and it is difficult to solve the inverse of the system response matrix, which are all approximate solutions. The realization of matrix inversion by digitally controlled resistors and operational amplifiers is a natural accurate solution. Hardware implementation can give full play to the speed advantage of hardware, has accurate timing information, has a natural parallel flight speed, superior event performance, low power consumption, and the solution used is a combination of digitally controlled resistors and operational amplifiers, with low electronic radiation, low interference, and lower cost than single-chip microcomputers or FPGAs. It is of great significance for image reconstruction of medical imaging systems such as PET and SPECT.

[0130] The above embodiments are described to facilitate those skilled in the art to understand and use the present application. It is obvious that those familiar with the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present application is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present application without departing from the scope of the present application should be within the scope of protection of the present application.

Claims

1. A fully simulated nuclide distribution imaging method, characterized in that: The method comprises the following steps: Step S1: Determine the parameters of the front-end signal detection module according to user requirements. Step S2: obtaining a scintillation pulse event signal obtained by converting a gamma photon received by a scintillation crystal in a front-end signal detection module through a photomultiplier tube; Step S3: Analyze the signal obtained by the signal detection module to obtain biological image projection data P; Step S4: according to the system geometry of the signal detection module, the system response matrix H is obtained by Monte Carlo simulation or analytical method, and the number of parameters in the matrix is ​​determined by looping through the matrix; Step S5: setting the resistance parameter of the corresponding digitally controlled resistor according to the size of each element in the system response matrix H; The resistance parameters of the corresponding digitally controlled resistors are set according to the size of each element in the system response matrix H, and the image reconstruction is realized by hardware method. The value of the system response matrix A is set as the parameters of the digitally controlled resistors and feedback resistors connected in parallel on the input circuit of the operational amplifier in the hardware circuit, and P is set as the output voltage signal of the operational amplifier; Step S6: setting the input voltage of the digitally controlled resistor circuit according to the size of each element in the projection data P, and then measuring the output voltage; Step S7: Perform data transmission conversion on the output voltage signal and display it.

2. The method for fully simulating nuclide distribution imaging according to claim 1, characterized in that: In the above step S1 , the parameters of the detection module are variable.

3. The method for fully simulating nuclide distribution imaging according to claim 1, characterized in that: The projection data obtained in the above step S3 are all non-negative.

4. The method for fully simulating nuclide distribution imaging according to claim 1, characterized in that: In the above step S4, the system response matrix is ​​fixed, which is determined by the system geometry of the signal detection module.

5. The method for fully simulating nuclide distribution imaging according to claim 1, characterized in that: In the above step S4, the system geometry is a circular regular polygon.

6. The method for fully simulating nuclide distribution imaging according to claim 1, characterized in that: In the above step S5, the resistance parameter of the set digitally controlled resistor is determined, and a fixed signal detection module corresponds to the fixed parameter.

7. The method for fully simulating nuclide distribution imaging according to claim 1, characterized in that: In the above step S5, both the input and output signals are analog signals.

8. The method for fully simulating nuclide distribution imaging according to claim 1 is characterized in that: In the above step S6, the output voltage is measured by multi-channel simultaneous measurement.

9. The method for fully simulating nuclide distribution imaging according to claim 1 is characterized in that: In the above step S7, the data transmission conversion is parallel.

10. The method for fully simulating nuclide distribution imaging according to claim 1 is characterized in that: In the above step S7, the voltage signal is converted into corresponding pixel values ​​in a one-to-one correspondence.

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