PET coincidence event judgment method, acquisition method and device for nuclear medicine imaging

Abstract

The present invention relates to the field of nuclear medicine technology, and specifically to a PET coincidence event judgment method, acquisition method and device for nuclear medicine imaging. The judgment method includes: obtaining a pulse trigger signal at the current moment; generating a first matrix based on the pulse trigger signal at the current moment; obtaining a second matrix corresponding to the pulse trigger signal in a preset time window before the current moment; adding the first matrix to the second matrix to obtain a combined matrix; performing an OR operation on each column in the combined matrix to generate a coincidence judgment matrix; and determining whether a coincidence event occurs based on the number of non-zero elements in the coincidence judgment matrix. The PET coincidence event judgment method provided by the present invention does not need to sort all data, and can simply calculate the pulse trigger signal in the preset time window before the current moment to determine whether a coincidence event occurs, thereby reducing the amount of calculation, collecting the time delay caused by random events, and achieving the real-time requirements of coincidence judgment.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear medicine, and in particular to a PET coincidence event judgment method, acquisition method and device for nuclear medicine imaging. Background Art

[0002] Positron emission tomography (PET) is a nuclear medicine imaging technology that can display the metabolism of biological molecules in vivo. It has been widely used in the differential diagnosis of various diseases, efficacy evaluation, and new drug development. Its detection principle is to obtain the three-dimensional distribution of radioactive drugs in the body by detecting a pair of photons with an energy of 511KeV and opposite propagation directions generated by the annihilation of positrons and electrons. The main function of the compliance judgment module is to select and pair the collected photons and provide effective annihilation data for subsequent imaging. Therefore, its correctness and timeliness directly determine the processing performance and diagnostic accuracy of the entire system. In recent years, with the increasing complexity of the PET application environment and the increasing demand for real-time PET imaging, further requirements have been put forward for the performance of the compliance judgment module.

[0003] Existing PET equipment usually includes multiple detectors, acquisition modules, and coincidence judgment modules, wherein the detectors are used to detect photons generated by the annihilation of positrons and electrons, and the acquisition modules collect the detection results of multiple detectors, and then send corresponding pulse trigger signals to the coincidence judgment module. Traditional coincidence judgment modules usually use analog coincidence circuit boards. This method is gradually becoming a bottleneck in the development of PET due to its complex design. In recent years, with the development of digital PET, digital coincidence judgment modules are gradually replacing traditional analog coincidence circuit boards. In the prior art, it is usually determined whether there is a coincidence event by detecting the photon pairs generated by the annihilation of positrons and electrons. The coincidence event mentioned here refers to the detected photon pairs reaching different detectors at the same time, so as to provide effective annihilation data for subsequent imaging. Photon pairs reaching different detectors within a very small time period can be considered as coincidence events, that is, they are generated and reach different detectors at the same time.

[0004] However, the inventors found that the digital coincidence judgment module in the prior art is still unable to perform effective collection judgment on the acquisition module and optimize the acquisition process due to the lack of real-time performance. With the increase in the sensitivity and complexity of PET equipment and the increasingly complex PET application scenarios, the data collection pressure of a single PET detector is increasing. Since the acquisition module of the PET equipment often does not have the ability to make coincidence judgments, when there are more random events (such as in BNCT dose detection or PET and CT acquisition at the same time), a large number of single events will occupy the system's power consumption, transmission bandwidth and other core performance, causing the system performance to decline.

[0005] At the same time, the current digital compliance module often realizes compliance judgment through data sorting. This algorithm has large amount of calculation, complex process and long calculation delay, and cannot meet the requirements of real-time feedback of the system. Summary of the invention

[0006] In view of this, the embodiments of the present invention provide a PET compliance event judgment method, collection method, device and electronic device to solve the problem in the prior art that the compliance judgment calculation is long and complex and cannot meet the real-time feedback requirements.

[0007] According to a first aspect, an embodiment of the present invention provides a PET coincidence event determination method for nuclear medicine imaging, comprising:

[0008] Acquire a pulse trigger signal at the current moment; wherein the pulse trigger signal is a pulse trigger signal corresponding to the photon generated after the detector detects the photon;

[0009] Generate a first matrix based on the pulse trigger signal at the current moment; wherein the first matrix is ​​a 1*M-dimensional matrix, M is the number of the detectors, and each element in the first matrix represents whether the corresponding detector corresponds to a pulse trigger signal at the current moment, wherein when the element is 0, it indicates that the corresponding detector does not correspond to a pulse trigger signal at the current moment, and when the element is 1, it indicates that the corresponding detector corresponds to a pulse trigger signal at the current moment;

[0010] Obtain a second matrix corresponding to a pulse trigger signal within a preset time window before the current moment; wherein the second matrix is ​​an N*M dimensional matrix, N is the size of the preset time window, the rows in the second matrix are sorted by time, and each element in the second matrix represents whether the corresponding detector corresponds to a pulse trigger signal at a corresponding moment in the preset time window, wherein when an element is 0, it indicates that the corresponding detector does not correspond to a pulse trigger signal at a corresponding moment in the preset time window, and when an element is 1, it indicates that the corresponding detector corresponds to a pulse trigger signal at a corresponding moment in the preset time window;

[0011] Adding the first matrix to the second matrix to obtain a combined (N+1)*M dimensional matrix;

[0012] Perform an OR operation on each column in the combined matrix to generate a compliance judgment matrix;

[0013] Whether a matching event occurs is determined according to the number of non-zero elements in the matching judgment matrix.

[0014] Optionally, determining whether a compliance event occurs based on the number of non-zero elements in the compliance judgment matrix includes: when the number of non-zero elements in the compliance judgment matrix is ​​less than or equal to 1, no compliance event occurs; when the number of non-zero elements in the compliance judgment matrix is ​​greater than or equal to 2, a compliance event occurs.

[0015] Optionally, the second matrix is ​​sorted from top to bottom in chronological order, and each column represents the elements corresponding to the same detector within a preset time window. The adding of the first matrix to the second matrix to obtain a combined (N+1)*M dimensional matrix includes: adding the first matrix as the N+1th row of the second matrix to the second matrix to obtain a combined (N+1)*M dimensional matrix; performing an OR operation on each column in the combined matrix to generate a compliance judgment matrix includes: performing an OR operation on the elements in each column of the combined matrix to obtain a 1*M dimensional matrix as the compliance judgment matrix.

[0016] Optionally, after determining whether a matching event occurs based on the number of non-zero elements in the matching judgment matrix, it also includes: using the 2nd to N+1th rows of the combined matrix as the second matrix corresponding to the pulse trigger signal within a preset time window before the next moment.

[0017] Optionally, generating the first matrix based on the pulse trigger signal at the current moment includes: generating an initial first matrix, which is a 0 matrix; based on the acquired pulse trigger signal at the current moment, changing the elements of the initial first matrix corresponding to the pulse trigger signal of the detector to 1, so as to update the initial first matrix and obtain the first matrix.

[0018] The PET coincidence event judgment method for nuclear medicine imaging provided by the embodiment of the present invention has the following beneficial effects: according to the pulse trigger signal at the current moment and the pulse trigger signal within the preset time window before the current moment, a first matrix and a second matrix are generated, and then each column is located after combining the first matrix and the second matrix to obtain a coincidence judgment matrix. It is only necessary to determine whether a coincidence event has occurred based on the number of non-zero elements in the coincidence judgment matrix, and there is no need to sort the data of the entire detection process, which reduces the amount of calculation, shortens the time delay caused by the calculation, and realizes the real-time feedback requirements of the coincidence judgment. In addition, the user can set the size of the preset time window according to the accuracy requirements, so that the application scenarios of the coincidence judgment are more extensive.

[0019] The PET coincidence event judgment method for nuclear medicine provided by the embodiment of the present invention has the following beneficial effects: (1) By using the matrix OR operation to determine whether a coincidence event has occurred, compared with the traditional coincidence judgment, there is no need to sort the data of the entire detection process, and the calculation is simple and fast. (2) The amount of data calculated is limited to the pulse signal within the current moment and the preset time window before the current moment, which saves system resources and calculation time and meets the requirements of real-time feedback.

[0020] According to the second aspect, an embodiment of the present invention provides a PET coincidence event acquisition method for nuclear medicine imaging, comprising: generating a pulse trigger signal at a current moment based on the detection result of the detector; using the PET coincidence event judgment method for nuclear medicine imaging described in the first aspect or any one embodiment of the first aspect, judging whether a coincidence event occurs based on the pulse trigger signal at the current moment; when no coincidence event occurs, not acquiring the detection result of the detector at the current moment; when a coincidence event occurs, acquiring the detection result of the detector at the current moment.

[0021] The PET coincidence event acquisition method for nuclear medicine imaging provided by the embodiment of the present invention directly acquires the detection result of the detector at the next moment if the pulse trigger signal at the current moment does not coincide with the occurrence of an event, and eliminates or does not acquire the pulse trigger signal at the current moment that does not coincide with the occurrence of an event, thereby saving the system's power consumption and data transmission bandwidth, and solving the problem of system performance degradation when the number of random events increases.

[0022] According to the third aspect, an embodiment of the present invention provides a PET system structure, including: multiple detectors for detecting photons; a first acquisition module, connected to the multiple detectors, for acquiring the detection results of the multiple detectors and generating a pulse trigger signal; a coincidence judgment circuit, connected to the first acquisition module, for executing the PET coincidence event judgment method for nuclear medicine imaging described in the first aspect or any one embodiment of the first aspect.

[0023] In the PET system provided by the embodiment of the present invention, the acquisition module generates a pulse trigger signal according to the detection results of multiple detectors, and the coincidence judgment module judges whether a coincidence event occurs according to the pulse trigger signal, and feeds back the judgment result to the acquisition module to control the acquisition module to collect the detection results of the multiple detectors. Since the coincidence judgment process is performed by the coincidence judgment module, the influence of a large number of single events caused by the complex acquisition environment on the power consumption and operation speed of the entire PET system is reduced.

[0024] According to a fourth aspect, an embodiment of the present invention provides a PET coincidence event judgment device for nuclear medicine imaging, comprising:

[0025] A first acquisition module is used to acquire a pulse trigger signal at the current moment; wherein the pulse trigger signal is a pulse trigger signal corresponding to the photon generated after the detector detects the photon;

[0026] A first matrix generating module, used to generate a first matrix based on the pulse trigger signal at the current moment; wherein the first matrix is ​​a 1*M-dimensional matrix, M is the number of the detectors, and each element in the first matrix represents whether the corresponding detector corresponds to a pulse trigger signal at the current moment, wherein when the element is 0, it indicates that the corresponding detector does not correspond to a pulse trigger signal at the current moment, and when the element is 1, it indicates that the corresponding detector corresponds to a pulse trigger signal at the current moment;

[0027] A second acquisition module is used to acquire a second matrix corresponding to a pulse trigger signal within a preset time window before the current moment; wherein the second matrix is ​​an N*M dimensional matrix, N is the size of the preset time window, the rows in the second matrix are sorted by time, and each element in the second matrix represents whether the corresponding detector corresponds to a pulse trigger signal at a corresponding moment in the preset time window, wherein when the element is 0, it indicates that the corresponding detector does not correspond to a pulse trigger signal at a corresponding moment in the preset time window, and when the element is 1, it indicates that the corresponding detector corresponds to a pulse trigger signal at a corresponding moment in the preset time window;

[0028] A combining module, used for adding the first matrix to the second matrix to obtain a combined (N+1)*M dimensional matrix;

[0029] An operation module is used to perform an OR operation on each column of the combined matrix to generate a compliance judgment matrix;

[0030] The conforming event determination module is used to determine whether a conforming event occurs according to the number of non-zero elements in the conforming judgment matrix.

[0031] The PET coincidence event judgment device for nuclear medicine imaging provided by the embodiment of the present invention generates a first matrix and a second matrix according to a pulse trigger signal at the current moment and a pulse trigger signal within a preset time window before the current moment, combines the first matrix with the second matrix, and performs a location operation on each column in the combined matrix to obtain a coincidence judgment matrix. According to the number of non-zero elements in the coincidence judgment matrix, it can be determined whether a coincidence event occurs. Compared with traditional coincidence judgment, the data range involved in the coincidence judgment is reduced to the current moment and the preset time window before the current moment, and there is no need to judge the data in the entire detection process, which reduces the amount of calculation, shortens the time delay caused by the calculation, and meets the requirements of real-time feedback of the coincidence judgment.

[0032] According to the fifth aspect, an embodiment of the present invention provides a PET coincidence event acquisition device for nuclear medicine imaging, including: a generation module, used to generate a pulse trigger signal at a current moment based on the detection result of the detector; a coincidence judgment module, used to adopt the PET coincidence event judgment method for nuclear medicine imaging described in the first aspect or any one embodiment of the first aspect, and judge whether a coincidence event occurs based on the pulse trigger signal at the current moment; a second acquisition module, used to not acquire the detection result of the detector at the current moment when no coincidence event occurs; when a coincidence event occurs, acquire the detection result of the detector at the current moment; a sending module, used to send the pulse information of the photon corresponding to the coincidence event to the back end when a coincidence event occurs.

[0033] The embodiment of the present invention provides a coincidence event acquisition device for nuclear medicine imaging. If the pulse trigger signal at the current moment does not coincide with the occurrence of an event, the detection result of the detector at the next moment is directly acquired, and the pulse trigger signal at the current moment that does not coincide with the occurrence of an event is eliminated or not acquired, thereby saving the system's power consumption and data transmission bandwidth, and solving the problem of system performance degradation when the number of random events increases.

[0034] According to the sixth aspect, an embodiment of the present invention provides an electronic device, comprising: a memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the PET coincidence event judgment method for nuclear medicine imaging described in the first aspect or any one embodiment of the first aspect, and / or the PET coincidence event acquisition method for nuclear medicine imaging described in the second aspect by executing the computer instructions.

[0035] According to the seventh aspect, an embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the PET coincidence event judgment method for nuclear medicine imaging described in the first aspect or any one embodiment of the first aspect, and / or the PET coincidence event acquisition method for nuclear medicine imaging described in the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1is a flow chart of a PET compliance event determination method provided in an embodiment of the present invention;

[0038] Figure 2 is a complete flow chart of a PET compliance event determination method provided according to an embodiment of the present invention;

[0039] Figure 3 is a complete flow chart of a PET compliance event determination method provided according to an embodiment of the present invention;

[0040] Figure 4 is a flow chart of a PET coincidence event acquisition method provided according to an embodiment of the present invention;

[0041] Figure 5 is a schematic diagram of the composition structure of a PET system provided according to an embodiment of the present invention;

[0042] Figure 6 is a schematic diagram of the complete composition structure of a PET system provided according to an embodiment of the present invention;

[0043] Figure 7 is a schematic structural diagram of a PET coincidence event determination device provided according to an embodiment of the present invention;

[0044] Figure 8 is a schematic structural diagram of a PET coincidence event collection device provided according to an embodiment of the present invention;

[0045] Fig. 9 It is a schematic diagram of the hardware structure of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 those skilled in the art without creative work are within the scope of protection of the present invention.

[0047] Example 1

[0048] The embodiment of the present invention provides a PET coincidence event determination method for nuclear medicine images. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than that shown here. The PET coincidence event determination method for nuclear medicine images provided in this embodiment can be used in the above-mentioned electronic devices, such as Figure 1As shown, the process includes the following steps:

[0049] S11, obtaining the pulse trigger signal at the current moment.

[0050] The pulse trigger signal is a pulse trigger signal corresponding to the photon generated after the detector detects the photon. Specifically, since the annihilated photon pair will have energy loss during the propagation process, which is less than the theoretical value of 511KeV, the quality of the annihilation data is reduced. Therefore, the embodiment of the present invention sets an energy threshold for the photons detected by the detector. When the detector detects photons greater than or equal to the energy threshold, or the acquisition module connected to the detector acquires the photons detected by the detector, a high level is issued, otherwise, a low level is issued. The high level and low level can be converted into digital signals "1" and "0", which are the pulse trigger signals described in the embodiment of the present invention.

[0051] The pulse trigger signal at the current moment acquired by the electronic device may be a pulse trigger signal generated after the detector detects photons in real time; it may be a pulse trigger signal generated after the acquisition module acquires photons detected by the detector; it may also be a pulse trigger signal at the current moment stored in advance in the electronic device; or it may be a pulse trigger signal at the current moment acquired by the electronic device from the outside through other means, etc. Regardless of how the electronic device acquires the pulse trigger signal at the current moment, it is only necessary to ensure that the electronic device can acquire the pulse trigger signal at the current moment.

[0052] S12, generating a first matrix based on the pulse trigger signal at the current moment.

[0053] Among them, the first matrix is ​​a 1*M dimensional matrix, M is the number of the detectors, and each element in the first matrix represents whether the corresponding detector corresponds to a pulse trigger signal at the current moment. When the element is 0, it indicates that the corresponding detector does not correspond to a pulse trigger signal at the current moment, and when the element is 1, it indicates that the corresponding detector corresponds to a pulse trigger signal at the current moment.

[0054] Specifically, at this moment, the pulse trigger signal generated by the 1st to Mth detectors after detecting photons is T 11 , T 12 , T 13 ……T 1M , the first matrix can be expressed as:

[0055] T=|T 11 T 12 T 13 …T 1M|; In practice, each of the detectors is provided with a number and stored in an electronic device. When the electronic device obtains a pulse trigger signal, it identifies the number of the detector corresponding to the pulse trigger signal, and generates the first matrix T based on the number. Alternatively, the electronic device can also obtain the pulse trigger signal and the detector number corresponding to the pulse trigger signal one by one from the output end of the acquisition module. At this time, the number is identified by the acquisition module.

[0056] S13, obtaining a second matrix corresponding to the pulse trigger signal within a preset time window before the current moment.

[0057] Among them, the second matrix is ​​an N*M dimensional matrix, N is the size of the preset time window, the rows in the second matrix are sorted according to time, and each element in the second matrix represents whether the corresponding detector corresponds to a pulse trigger signal at a corresponding moment in the preset time window. When the element is 0, it indicates that the corresponding detector does not correspond to a pulse trigger signal at a corresponding moment in the preset time window, and when the element is 1, it indicates that the corresponding detector corresponds to a pulse trigger signal at a corresponding moment in the preset time window.

[0058] Specifically, assuming that the detector or the acquisition module generates a set of data every 10ns (nanoseconds), the preset time window can be set to 10*Nns, where N is a natural number, that is, the preset time window before the current moment can be understood as the first 10ns, the second 10ns, the third 10ns, and the fourth 10ns before the current moment. The pulse trigger signal within the preset time window before the current moment can be represented by Table 1:

[0059] Table 1 Pulse trigger signal within the preset time window before the current moment

[0060]

[0061] Among them, J in Table 1 NM represents the pulse trigger signal corresponding to the Mth detector in the Nth 10ns before the current moment. Then the second matrix can be expressed as:

[0062]

[0063] Among them, M is the number of detectors, N is the size of the preset time window, and the preset time window can be set according to the generation clock of the pulse trigger signal. For example, when the generation clock of the pulse trigger signal is 10ns, then N can be set to an integer multiple of the clock. The smaller N is, the more stringent the system acquisition requirements are, and the higher the accuracy of compliance judgment is. That is, the initial screening of the time interval between the two photons that produce annihilation and arrive at the two detectors is determined by setting the size of N, and N can be set according to needs.

[0064] S14, adding the first matrix to the second matrix to obtain a combined (N+1)*M dimensional matrix.

[0065] Specifically, the first matrix T is used as the N+1th row of the second matrix J, and the combined matrix is:

[0066]

[0067] S15, performing an OR operation on each column in the combined matrix to generate a compliance judgment matrix.

[0068] Specifically, the matrix J * Perform an OR operation on each column element in to obtain the compliance judgment matrix K. The elements in K can be calculated by the following formula:

[0069] K 11 =J 11 ||J 21 ||J 31 ||…||J N1 ||T 11 ;

[0070] K 12 =J 12 ||J 22 ||J 32 ||…||J N2 ||T 12 ;

[0071] K 13 =J 13 ||J 23 ||J 33 ||…||J N3 ||T 13 ;

[0072] K 1M =J 1M ||J 2M ||J 3M ||…||J NM ||T 1M .

[0073] Then the compliance judgment matrix is: K = |K 11 K 12 K 13 …K 1M |. The following is an example of the specific calculation process that meets the judgment matrix K:

[0074] Taking M=4, N=3 as an example, assuming that the first matrix T=|10 01|, that is, at the current moment, the energy of the photons detected by the first detector and the fourth detector is greater than or equal to the energy threshold, and a pulse trigger signal "1" is generated respectively;

[0075] Second Matrix That is, the second detector generates a pulse trigger signal "1" at the second 10ns before the current moment;

[0076] The first matrix T is used as the N+1th row of the second matrix J to obtain the combined matrix J * :

[0077]

[0078] The matrix J * Perform an OR operation on each column element in to obtain the compliance judgment matrix K:

[0079] K 11 =0||0||0||1;

[0080] K 12 =0||0||0||0;

[0081] K 13 =0||0||0||0;

[0082] K 14 =0||1||0||0;

[0083] Then, the compliance judgment matrix K = |1 0 0 1|.

[0084] S16, determining whether a matching event occurs according to the number of non-zero elements in the matching judgment matrix.

[0085] Specifically, the above matrix J * The elements in the 1st to 4th columns represent the photon detection status of the 1st detector, the 2nd detector, the 3rd detector and the 4th detector at the current moment and the 1st 10ns, the 2nd 10ns and the 3rd 10ns before the current moment, respectively. "1" means there is a pulse trigger signal, that is, photons that meet the energy threshold are generated.

[0086] The judgment condition for the event is: a photon pair reaches two different detectors at the same time. * Each column element in is ORed to obtain a compliance judgment matrix K, which can be used to determine whether the detector detects photons that meet the energy threshold requirements at the current moment and within the preset time window before the current moment. That is, based on the number of non-zero elements in the compliance judgment matrix K, it can be determined whether a compliance event occurs.

[0087] The PET coincidence event judgment method for nuclear medicine imaging provided by the embodiment of the present invention has the following beneficial effects: (1) According to the pulse trigger signal at the current moment and the pulse trigger signal within the preset time window before the current moment, a first matrix and a second matrix are generated, and then the first matrix and the second matrix are combined and each column is located to obtain a coincidence judgment matrix. It is only necessary to determine whether a coincidence event occurs according to the number of non-zero elements in the coincidence judgment matrix, without sorting the data of the entire detection process, reducing the amount of calculation, reducing the time delay caused by the calculation, and realizing the real-time feedback requirement of coincidence judgment. In addition, the user can set the size of the preset time window according to the accuracy requirement, so that the application scenario of coincidence judgment is more extensive. (2) The embodiment of the present invention sets an energy threshold for the photons detected by the detector. Only when it is greater than or equal to the energy threshold, a pulse trigger signal will be generated, which not only reduces the power consumption of the system, but also makes the coincidence judgment more accurate and ensures the quality of annihilation data.

[0088] Alternatively, if Figure 2 As shown, the above S16 may include:

[0089] S161: When the number of non-zero elements in the compliance judgment matrix is ​​less than or equal to 1, no compliance event occurs.

[0090] S162: When the number of non-zero elements in the compliance judgment matrix is ​​greater than or equal to 2, a compliance event occurs.

[0091] Specifically, the result of the OR operation is 1, which means that the detector corresponding to the element in this column has detected a photon; when the results of the OR operation of at least two columns are non-zero (that is, 1), it indicates that at least two detectors have detected photons that meet the energy requirements, and it can be determined that a matching event has occurred; otherwise, no matching event has occurred.

[0092] Optionally, Figure 3 is a complete flow chart of the compliance determination method according to an embodiment of the present invention, such as Figure 3 As shown, the process includes:

[0093] S101, obtaining a pulse trigger signal at the current moment.

[0094] For details, please see Figure 1 The S11 described above will not be described in detail here.

[0095] S102, generating a first matrix based on the pulse trigger signal at the current moment. Optionally, generating an initial first matrix, the initial first matrix is ​​a 0 matrix; based on the acquired pulse trigger signal at the current moment, changing the elements of the initial first matrix corresponding to the detector having the pulse trigger signal to 1, so as to update the initial first matrix and obtain the first matrix.

[0096] S103, obtaining a second matrix corresponding to the pulse trigger signal in a preset time window before the current moment. Optionally, the second matrix is ​​sorted from top to bottom in chronological order, and each column represents an element corresponding to the same detector in the preset time window.

[0097] S104, adding the first matrix to the second matrix to obtain a combined (N+1)*M dimensional matrix. Optionally, adding the first matrix as the N+1th row of the second matrix to the second matrix to obtain a combined (N+1)*M dimensional matrix.

[0098] S105, performing an OR operation on each column of the combined matrix to generate a compliance judgment matrix. Optionally, performing an OR operation on the elements of each column of the combined matrix to obtain a 1*M dimensional matrix as the compliance judgment matrix.

[0099] S106, judging whether the number of non-zero elements in the compliance judgment matrix is ​​greater than or equal to 2. When the number of non-zero elements in the compliance judgment matrix is ​​less than 2, no compliance event occurs, and S107 is executed; when the number of non-zero elements in the compliance judgment matrix is ​​greater than or equal to 2, step S108 is executed.

[0100] S107, obtaining a pulse trigger signal at the next moment. Specifically, when no matching event occurs, that is, when a single event occurs, the information of the photons corresponding to the single event is discarded, or the photons corresponding to the single event are not collected directly.

[0101] S108, using the 2nd to N+1th rows of the combined matrix as the second matrix corresponding to the pulse trigger signal within a preset time window before the next moment.

[0102] The PET coincidence event judgment method for nuclear medicine provided by the embodiment of the present invention has the following beneficial effects: (1) By using the matrix OR operation to determine whether a coincidence event has occurred, compared with the traditional coincidence judgment, there is no need to sort the data of the entire detection process, and the calculation is simple and fast. (2) The amount of data calculated is limited to the pulse signal within the current moment and the preset time window before the current moment, which saves system resources and calculation time and meets the requirements of real-time feedback.

[0103] Example 2

[0104] The embodiment of the present invention provides a PET coincidence event acquisition method for nuclear medicine images. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than that shown here. The PET coincidence event acquisition method for nuclear medicine images provided in this embodiment can be used in the above-mentioned electronic devices, such as Figure 4 As shown, the process includes the following steps:

[0105] S21, generating a pulse trigger signal at the current moment based on the detection result of the detector.

[0106] Specifically, the detector can be a photomultiplier tube or a silicon photomultiplier device (SiPM) or a semiconductor device, which converts the detected light signal into an electrical signal. In order to ensure the quality of the annihilation data, an energy threshold is set. Only when a light signal greater than the energy threshold is generated for the first time, the detector or the acquisition module connected to the detector will generate a pulse trigger signal "1".

[0107] S22, using Figure 1-Figure 3 The method for determining a matching event described in any one of the embodiments is to determine whether a matching event occurs based on the pulse trigger signal at the current moment. When no matching event occurs, S23 is executed; when a matching event occurs, S24 is executed.

[0108] S23, do not collect the detection results of the detector at the current moment. Specifically, if no matching event occurs, that is, when a single event occurs, the optical signal corresponding to the single event, including the converted electrical signal, is discarded, or the optical signal (or electrical signal) corresponding to the single event is not collected directly.

[0109] S24, collecting the detection results of the detector at the current moment. Specifically, if a coincidence event occurs, a preset level signal is generated as a coincidence signal corresponding to the coincidence event, so as to send the pulse information of the photon corresponding to the coincidence event to the back end for imaging. The pulse information may include: time information, position information and energy information of the pulse.

[0110] The method for collecting PET coincident events for nuclear medicine imaging provided by an embodiment of the present invention directly collects the detection result of the detector at the next moment if the pulse trigger signal at the current moment does not correspond to the occurrence of an event, and eliminates or does not collect the pulse trigger signal at the current moment that does not correspond to the occurrence of an event, thereby saving the power consumption and data transmission bandwidth of the system and solving the problem of system performance degradation when the number of random events increases.

[0111] Example 3

[0112] The embodiment of the present invention provides a PET system, such as Figure 5 As shown, it includes: a plurality of detectors 01 for detecting photons; a first acquisition module 02 connected to the plurality of detectors 01 for collecting the detection results of the plurality of detectors 01 and generating a pulse trigger signal; a compliance judgment circuit 03 connected to the first acquisition module 02 for executing Figure 1-Figure 3 The PET described in any one of the embodiments is consistent with the event determination method.

[0113] The multiple detectors 01 may be multiple photomultiplier devices, used to detect photons and convert optical signals into electrical signals. The first acquisition module 02 is connected to the multiple detectors 01. It may be that multiple detectors 01 correspond to one first acquisition module 02, or it may be that multiple detectors 01 correspond to one first acquisition module 02. The present invention does not limit this. The first acquisition module 02 is used to collect the electrical signal, generate a pulse trigger signal and send it to the compliance judgment circuit 03. The compliance judgment circuit 03 determines whether a compliance event occurs based on the pulse trigger signal and feeds back to the first acquisition module 02. The specific judgment process is detailed in Figure 1-Figure 3 , no longer elaborated here, after the first acquisition module 02 receives the coincidence signal sent by the coincidence judgment circuit 03, it sends the pulse information of the photon corresponding to the coincidence event to other back-ends for imaging; if the coincidence signal is not received, it waits for the electrical signal of the photon at the current moment to end and performs acquisition at the next moment.

[0114] Furthermore, if Figure 6As shown, the first acquisition module 02 includes a main acquisition module, a pulse trigger signal generating module, an energy acquisition module, a position acquisition module, a time acquisition module and a first main control. The first main control can adopt FPGA or ASIC, and is connected to the output end of the compliance judgment circuit 03 (not shown in the figure) to determine whether there is a compliance signal. When the first main control receives the compliance signal, it controls the energy acquisition module, the position acquisition module, and the time acquisition module to obtain the energy information, the position information, and the time information of the photon; when the first main control does not receive the compliance signal, it controls the main acquisition module to wait for the end of the current moment, that is, controls the main acquisition module not to collect the electrical signal of the photon for which no compliance event has occurred.

[0115] The conformity judgment circuit 03 includes a primary clock synchronization module, a first main control and a data processing module. The primary clock synchronization module is located on the backplane of the conformity judgment circuit 03 and is connected to the multiple detectors 01 (not shown in the figure), and is used to synchronize the clocks of the multiple detectors 01 with the clock of the entire system. Specifically, the clock synchronization module generates a synchronous clock signal and distributes it to the multiple detectors 01, and the multiple detectors 01 adjust the clock according to the synchronous clock signal. In addition, a secondary clock module (not shown in the figure) is provided in the time acquisition module of the first acquisition module 02, and the secondary clock module is used to calculate the time information of the arrival of the photon. The data processing module is used to perform conformity judgment calculations, data compression, transmission to other backends, etc. The processing module can be implemented by an FPGA module or an ASIC module.

[0116] The PET system provided by the embodiment of the present invention reduces the impact of a large number of single events caused by a complex acquisition environment on the power consumption and operating speed of the entire PET system, and saves the data transmission bandwidth of the system, because clock synchronization and coincidence judgment are both completed in the coincidence judgment circuit.

[0117] Example 4

[0118] In this embodiment, a PET coincidence event judgment device for nuclear medicine imaging is provided, which is used to implement the above-mentioned embodiments and preferred implementation modes, and the descriptions that have been made are not repeated here. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0119] The embodiment of the present invention provides a PET coincidence event judgment device for nuclear medicine imaging, such as Figure 7 As shown, the device comprises:

[0120] The first acquisition module 31 is used to acquire a pulse trigger signal at the current moment; wherein the pulse trigger signal is a pulse trigger signal corresponding to the photon generated after the detector detects the photon;

[0121] A first matrix generating module 32 is used to generate a first matrix based on the pulse trigger signal at the current moment; wherein the first matrix is ​​a 1*M-dimensional matrix, M is the number of the detectors, and each element in the first matrix represents whether the corresponding detector corresponds to a pulse trigger signal at the current moment, wherein when the element is 0, it indicates that the corresponding detector does not correspond to a pulse trigger signal at the current moment, and when the element is 1, it indicates that the corresponding detector corresponds to a pulse trigger signal at the current moment;

[0122] The second acquisition module 33 is used to obtain a second matrix corresponding to a pulse trigger signal in a preset time window before the current moment; wherein the second matrix is ​​an N*M dimensional matrix, N is the size of the preset time window, the rows in the second matrix are sorted by time, and each element in the second matrix represents whether the corresponding detector corresponds to a pulse trigger signal at a corresponding moment in the preset time window, wherein when the element is 0, it indicates that the corresponding detector does not correspond to a pulse trigger signal at a corresponding moment in the preset time window, and when the element is 1, it indicates that the corresponding detector corresponds to a pulse trigger signal at a corresponding moment in the preset time window;

[0123] A combining module 34, configured to add the first matrix to the second matrix to obtain a combined (N+1)*M dimensional matrix;

[0124] An operation module 35 is used to perform an OR operation on each column in the combined matrix to generate a compliance judgment matrix;

[0125] The conforming event determination module 36 is used to determine whether a conforming event occurs according to the number of non-zero elements in the conforming judgment matrix.

[0126] The PET coincidence event judgment device for nuclear medicine imaging in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC circuit, a processor and a memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions. The further functional description of each of the above modules is the same as that of the above corresponding embodiment, and will not be repeated here.

[0127] The PET coincidence event judgment device for nuclear medicine imaging provided by the embodiment of the present invention has the following beneficial effects: (1) According to the pulse trigger signal at the current moment and the pulse trigger signal within the preset time window before the current moment, a first matrix and a second matrix are generated, and then the first matrix and the second matrix are combined and each column is ORed to obtain a coincidence judgment matrix. It is only necessary to determine whether a coincidence event occurs according to the number of non-zero elements in the coincidence judgment matrix, without sorting the data of the entire detection process, thereby reducing the amount of calculation, reducing the time delay caused by the calculation, and realizing the real-time feedback requirement of coincidence judgment. In addition, the user can set the size of the preset time window according to the accuracy requirement, so that the application scenario of coincidence judgment is more extensive. (2) The embodiment of the present invention sets an energy threshold for the photons detected by the detector. Only when it is greater than or equal to the energy threshold, a pulse trigger signal will be generated, which not only reduces the power consumption of the system, but also makes the coincidence judgment more accurate and ensures the quality of annihilation data.

[0128] The PET coincidence event judgment device for nuclear medicine provided by the embodiment of the present invention has the following beneficial effects: (1) By determining whether a coincidence event occurs through matrix OR operation, compared with the traditional coincidence judgment, there is no need to sort the data of the entire detection process, and the calculation is simple and fast. (2) The amount of calculated data is limited to the pulse signal within the current moment and the preset time window before the current moment, which saves system resources and calculation time and meets the requirements of real-time feedback.

[0129] Example 5

[0130] In this embodiment, a PET coincidence event acquisition device for nuclear medicine imaging is provided, which is used to implement the above-mentioned embodiments and preferred implementation modes, and the descriptions that have been made will not be repeated. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0131] The embodiment of the present invention provides a PET coincidence event acquisition device for nuclear medicine imaging, such as Figure 8 As shown, the device comprises:

[0132] A generating module 41, used to generate a pulse trigger signal at a current moment based on the detection result of the detector;

[0133] A compliance judgment module 42, configured to use the PET compliance event judgment method according to any one of claims 1 to 5 to judge whether a compliance event occurs based on the pulse trigger signal at the current moment;

[0134] The second collection module 43 is used for not collecting the detection result of the detector at the current moment when no matching event occurs; and collecting the detection result of the detector at the current moment when a matching event occurs;

[0135] The sending module 44 is used to send the pulse information of the photon corresponding to the event to the back end when a matching event occurs.

[0136] The PET coincidence event acquisition device for nuclear medicine imaging in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC circuit, a processor and a memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions. The further functional description of each of the above modules is the same as that of the above corresponding embodiment, and will not be repeated here.

[0137] The PET coincidence event acquisition device for nuclear medicine imaging provided by the embodiment of the present invention directly acquires the detection result of the detector at the next moment if the pulse trigger signal at the current moment does not correspond to the occurrence of an event, and eliminates or does not acquire the pulse trigger signal at the current moment that does not correspond to the occurrence of an event, thereby saving the system's power consumption and data transmission bandwidth, and solving the problem of system performance degradation when the number of random events increases.

[0138] Example 6

[0139] An embodiment of the present invention provides an electronic device having Figure 7 The PET coincidence event determination device for nuclear medicine imaging and / or Figure 8 A PET coincidence event acquisition device for nuclear medicine imaging is shown.

[0140] See also Fig. 9 , Fig. 9 is a schematic diagram of the structure of an electronic device provided by an optional embodiment of the present invention, such as Fig. 9As shown, the electronic device may include: at least one processor 51, such as a CPU (Central Processing Unit), at least one communication interface 53, a memory 54, and at least one communication bus 52. The communication bus 52 is used to realize the connection and communication between these components. The communication interface 53 may include a display screen (Display) and a keyboard (Keyboard), and the optional communication interface 53 may also include a standard wired interface and a wireless interface. The memory 54 may be a high-speed RAM memory (Random Access Memory) or a non-volatile memory (non-volatile memory), such as at least one disk storage. The memory 54 may optionally be at least one storage device located away from the aforementioned processor 51. The processor 51 may be combined with Figure 7 and / or Figure 8 In the described device, the memory 54 stores an application program, and the processor 51 calls the program code stored in the memory 54 to execute any of the above method steps.

[0141] The communication bus 52 may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus. The communication bus 52 may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Fig. 9 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0142] Among them, the memory 54 may include a volatile memory (English: volatile memory), such as a random access memory (English: random-access memory, abbreviated: RAM); the memory may also include a non-volatile memory (English: non-volatile memory), such as a flash memory (English: flash memory), a hard disk drive (English: hard disk drive, abbreviated: HDD) or a solid-state drive (English: solid-state drive, abbreviated: SSD); the memory 54 may also include a combination of the above types of memory.

[0143] The processor 51 may be a central processing unit (CPU), a network processor (NP), or a combination of a CPU and a NP.

[0144] The processor 51 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0145] Optionally, the memory 54 is also used to store program instructions. The processor 51 can call the program instructions to implement the present application Figure 1-Figure 3 Any of the PET coincidence event determination methods for nuclear medicine imaging shown in any one of the items, and / or, Figure 4 PET for nuclear medicine imaging shown corresponds to the event acquisition method.

[0146] Example 7

[0147] The embodiment of the present invention also provides a non-transitory computer storage medium, wherein the computer storage medium stores computer executable instructions, and the computer executable instructions can execute the PET coincidence event judgment method for nuclear medicine imaging and / or the PET coincidence event acquisition method for nuclear medicine imaging in any of the above method embodiments. The storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), a random access memory (RAM), a flash memory, a hard disk drive (HDD) or a solid-state drive (SSD), etc.; the storage medium can also include a combination of the above types of memory.

[0148] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A PET coincidence event determination method for nuclear medicine imaging, characterized in that: include: Acquire a pulse trigger signal at the current moment; wherein the pulse trigger signal is a pulse trigger signal corresponding to the photon generated after the detector detects the photon; Generate a first matrix based on the pulse trigger signal at the current moment; wherein the first matrix is ​​a 1*M-dimensional matrix, M is the number of the detectors, and each element in the first matrix represents whether the corresponding detector corresponds to a pulse trigger signal at the current moment, wherein when the element is 0, it indicates that the corresponding detector does not correspond to a pulse trigger signal at the current moment, and when the element is 1, it indicates that the corresponding detector corresponds to a pulse trigger signal at the current moment; Obtain a second matrix corresponding to a pulse trigger signal within a preset time window before the current moment; wherein the second matrix is ​​an N*M dimensional matrix, N is the size of the preset time window, the rows in the second matrix are sorted by time, and each element in the second matrix represents whether the corresponding detector corresponds to a pulse trigger signal at a corresponding moment in the preset time window, wherein when an element is 0, it indicates that the corresponding detector does not correspond to a pulse trigger signal at a corresponding moment in the preset time window, and when an element is 1, it indicates that the corresponding detector corresponds to a pulse trigger signal at a corresponding moment in the preset time window; Adding the first matrix to the second matrix to obtain a combined (N+1)*M dimensional matrix; Perform an OR operation on each column in the combined matrix to generate a compliance judgment matrix; Whether a matching event occurs is determined according to the number of non-zero elements in the matching judgment matrix.

2. The method according to claim 1, characterized in that The determining whether a matching event occurs according to the number of non-zero elements in the matching judgment matrix includes: When the number of non-zero elements in the compliance judgment matrix is ​​less than or equal to 1, no compliance event occurs; When the number of non-zero elements in the compliance judgment matrix is ​​greater than or equal to 2, a compliance event occurs.

3. The method according to claim 1, characterized in that The second matrix is ​​sorted from top to bottom in chronological order, and each column represents the element corresponding to the same detector within a preset time window. The adding the first matrix to the second matrix to obtain a combined (N+1)*M dimensional matrix includes: adding the first matrix as the N+1th row of the second matrix to the second matrix to obtain a combined (N+1)*M dimensional matrix; The performing an OR operation on each column of the combined matrix to generate a compliance judgment matrix includes: performing an OR operation on the elements of each column of the combined matrix to obtain a 1*M dimensional matrix as the compliance judgment matrix.

4. The method according to any one of claims 1 to 3, characterized in that: After determining whether a matching event occurs according to the number of non-zero elements in the matching judgment matrix, the method further includes: The 2nd to N+1th rows of the combined matrix are used as the second matrix corresponding to the pulse trigger signal within the preset time window before the next moment.

5. The method according to any one of claims 1 to 3, characterized in that: The generating a first matrix based on the pulse trigger signal at the current moment includes: Generate an initial first matrix, wherein the initial first matrix is ​​a 0 matrix; Based on the acquired pulse trigger signal at the current moment, the elements of the detector corresponding to the pulse trigger signal in the initial first matrix are changed to 1 to update the initial first matrix to obtain the first matrix.

6. A PET coincidence event acquisition method for nuclear medicine imaging, characterized in that: include: Generate a pulse trigger signal at the current moment based on the detection result of the detector; Adopting the PET coincidence event judgment method for nuclear medicine imaging according to any one of claims 1 to 5, judging whether a coincidence event occurs based on the pulse trigger signal at the current moment; When no matching event occurs, the detection results of the detector at the current moment are not collected; When a matching event occurs, the detection results of the detector at the current moment are collected.

7. A PET system, characterized in that: include: multiple detectors for detecting photons; A first acquisition module, connected to the multiple detectors, for acquiring detection results of the multiple detectors and generating a pulse trigger signal; A coincidence judgment circuit is connected to the first acquisition module and is used to execute the PET coincidence event judgment method for nuclear medicine imaging according to any one of claims 1 to 5.

8. A PET coincidence event judgment device for nuclear medicine imaging, characterized in that: include: A first acquisition module is used to acquire a pulse trigger signal at the current moment; wherein the pulse trigger signal is a pulse trigger signal corresponding to the photon generated after the detector detects the photon; A first matrix generating module, used to generate a first matrix based on the pulse trigger signal at the current moment; wherein the first matrix is ​​a 1*M-dimensional matrix, M is the number of the detectors, and each element in the first matrix represents whether the corresponding detector corresponds to a pulse trigger signal at the current moment, wherein when the element is 0, it indicates that the corresponding detector does not correspond to a pulse trigger signal at the current moment, and when the element is 1, it indicates that the corresponding detector corresponds to a pulse trigger signal at the current moment; A second acquisition module is used to acquire a second matrix corresponding to a pulse trigger signal within a preset time window before the current moment; wherein the second matrix is ​​an N*M dimensional matrix, N is the size of the preset time window, the rows in the second matrix are sorted by time, and each element in the second matrix represents whether the corresponding detector corresponds to a pulse trigger signal at a corresponding moment in the preset time window, wherein when the element is 0, it indicates that the corresponding detector does not correspond to a pulse trigger signal at a corresponding moment in the preset time window, and when the element is 1, it indicates that the corresponding detector corresponds to a pulse trigger signal at a corresponding moment in the preset time window; A combining module, used for adding the first matrix to the second matrix to obtain a combined (N+1)*M dimensional matrix; An operation module is used to perform an OR operation on each column of the combined matrix to generate a compliance judgment matrix; The conforming event determination module is used to determine whether a conforming event occurs according to the number of non-zero elements in the conforming judgment matrix.

9. A PET coincidence event acquisition device for nuclear medicine imaging, characterized in that: include: A generating module, used for generating a pulse trigger signal at a current moment based on the detection result of the detector; A coincidence judgment module, used to use the PET coincidence event judgment method for nuclear medicine imaging according to any one of claims 1 to 5 to judge whether a coincidence event occurs based on the pulse trigger signal at the current moment; The second collection module is used for not collecting the detection result of the detector at the current moment when no matching event occurs; and collecting the detection result of the detector at the current moment when a matching event occurs; The sending module is used to send the pulse information of the photon corresponding to the event to the back end when a matching event occurs.

10. An electronic device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the PET coincidence event determination method for nuclear medicine imaging as described in claims 1-5, and / or the PET coincidence event acquisition method for nuclear medicine imaging as described in claim 6.

11. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the PET coincidence event judgment method for nuclear medicine imaging described in claims 1-5, and / or the PET coincidence event acquisition method for nuclear medicine imaging described in claim 6.

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