Method and system for correcting dead time of PET (positron emission tomography) detector and PET system

Abstract

The invention relates to a PET detector dead time correction method and system and a PET system. The method comprises the following steps: adding a preset trigger signal to an input signal of a PET detector; determining a delay coincidence event of the trigger signal in the output signal of the PET detector; determining a dead time correction factor of the PET detector according to the number of the delay coincidence events; and performing dead time correction on the PET detector according to the dead time correction factor. By adopting the method, the dead time correction error of the PET detector can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of signal processing, and particularly to a method and system for dead time correction of a PET detector and a PET system. Background Art

[0002] During the process of a PET (Positron Emission Tomography) system's detector module processing signals, it is unable to respond to the next signal received within the current time period, resulting in fewer signals recorded by the electronics module than those detected by the detector. This effect is called the dead time effect, and the dead time effect causes the SUV (Standard Uptake Value) of the generated image to be lower than the actual value.

[0003] Currently, the dead time correction factor is usually determined based on the single event count rate given by the detector module and the DTC (DeadTime Correction) table obtained from a radioactive source experiment. However, since the electronics module of the detector screens the signals step by step, the single event count rates corresponding to different electronics modules are not the same, and the finally obtained single event count rate is difficult to represent the count rate of the entire detector, resulting in a large error in dead time correction.

[0004] Therefore, there is a problem of large error in the current dead time correction technology. Summary of the Invention

[0005] Based on this, in view of the above technical problems, it is necessary to provide a dead time correction method, system, device, computer device, computer-readable storage medium, computer program product, and PET system that can reduce errors.

[0006] In a first aspect, the present application provides a method for dead time correction of a PET detector. The method includes:

[0007] Adding a preset trigger signal to the input signal of the PET detector;

[0008] Determining the delay coincidence event of the trigger signal in the output signal of the PET detector;

[0009] Determining the dead time correction factor of the PET detector according to the number of events of the delay coincidence event;

[0010] Performing dead time correction on the PET detector according to the dead time correction factor.

[0011] In one embodiment, the determining the delay coincidence event of the trigger signal in the output signal of the PET detector includes:

[0012] Perform a delay process on the logic signal corresponding to the trigger signal to obtain a delayed signal of the logic signal;

[0013] Extract a delayed coincidence event of the trigger signal from the output signal according to the delayed signal.

[0014] In one embodiment, the determining the dead time correction factor of the PET detector according to the number of events of the delayed coincidence event includes:

[0015] Determine the number of signals of the trigger signal according to the logic signal corresponding to the trigger signal;

[0016] Obtain the dead time correction factor of the PET detector according to the ratio of the number of events of the delayed coincidence event to the number of signals of the trigger signal.

[0017] In one embodiment, the performing dead time correction on the PET detector according to the dead time correction factor includes:

[0018] Obtain the number of corrected signals corresponding to the number of output signals according to the ratio of the output signal to the dead time correction factor.

[0019] In a second aspect, the present application further provides a dead time correction system for a PET detector. The system includes a signal generator and a correction module; the signal generator is connected to a preamplifier of the PET detector;

[0020] The signal generator is configured to generate a preset trigger signal and input the trigger signal into the preamplifier; the preamplifier adds the trigger signal to the input signal of the PET detector;

[0021] The correction module is configured to determine the dead time correction factor of the PET detector according to the number of events of the delayed coincidence event of the trigger signal, and perform dead time correction on the PET detector according to the dead time correction factor.

[0022] In one embodiment, the system further includes a coincidence module, and the coincidence module is connected to both the signal generator and the correction module;

[0023] The signal generator is further configured to send the logic signal corresponding to the trigger signal to the coincidence module;

[0024] The coincidence module is used to perform delay processing on the logic signal, extract the delayed coincidence events of the trigger signal from the output signal of the PET detector according to the obtained delayed signal of the logic signal, and send the delayed coincidence events to the correction module.

[0025] In one embodiment, the coincidence module is further used to determine the number of signals of the trigger signal according to the logic signal, and send the number of signals to the correction module;

[0026] The correction module is further used to obtain the dead time correction factor of the PET detector according to the ratio of the number of events of the delayed coincidence event to the number of signals, and perform dead time correction on the output signal according to the dead time correction factor to obtain the corrected signal number corresponding to the number of the output signals.

[0027] In a third aspect, the present application further provides a device for correcting the dead time of a PET detector. The device includes:

[0028] A signal adding module, configured to add a preset trigger signal to the input signal of the PET detector;

[0029] An event determining module, configured to determine the delayed coincidence events of the trigger signal in the output signal of the PET detector;

[0030] A factor determining module, configured to determine the dead time correction factor of the PET detector according to the number of events of the delayed coincidence event;

[0031] A target correction module, configured to perform dead time correction on the PET detector according to the dead time correction factor.

[0032] In a fourth aspect, the present application further provides a computer device. The computer device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the dead time correction method according to any one of the above first aspects is implemented.

[0033] In a fifth aspect, the present application further provides a computer-readable storage medium. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the dead time correction method according to any one of the above first aspects is implemented.

[0034] In a sixth aspect, the present application further provides a computer program product. The computer program product includes a computer program, and when the computer program is executed by a processor, the dead time correction method according to any one of the above first aspects is implemented.

[0035] In a seventh aspect, the present application further provides a PET system. The system includes a PET detector and the PET detector dead time correction system according to any one of the above second aspects.

[0036] For the above PET detector dead time correction method, system, device, computer device, storage medium, computer program product, and PET system, by adding a preset trigger signal to the input signal of the PET detector, in the output signal of the PET detector, determining the delay coincidence event of the trigger signal, determining the dead time correction factor of the PET detector according to the number of events of the delay coincidence event, and performing dead time correction on the PET detector according to the dead time correction factor; a known trigger signal can be added to the input signal of the PET detector in real time, and by measuring the number of delay coincidence events in the detector output signal, the dead time correction factor for the current scan can be obtained. Since the dead time correction factor does not need to be determined according to the DTC correction table, the accuracy is relatively high, and the error of dead time correction can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic flowchart of a method for correcting the dead time of a PET detector in an embodiment;

[0038] Figure 2 is a schematic diagram of a PET system in an embodiment;

[0039] Figure 3 is a schematic diagram of a delay coincidence event in an embodiment;

[0040] Figure 4 is a structural block diagram of a PET detector dead time correction system in an embodiment;

[0041] Figure 5 is a structural block diagram of a PET system in an embodiment;

[0042] Figure 6 is a structural block diagram of a PET detector dead time correction device in an embodiment;

[0043] Figure 7 is an internal structure diagram of a computer device in an embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] In order to make the objectives, technical solutions, and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0045] In an embodiment, as Figure 1As shown, a method for correcting the dead time of a PET detector is provided. In this embodiment, taking the application of this method to a PET system as an example, the method includes the following steps:

[0046] Step S110: Add a preset trigger signal to the input signal of the PET detector.

[0047] Among them, the trigger signal can be a pulse signal generated by a signal generator.

[0048] In specific implementation, in order to determine the dead time correction factor of the PET detector, trigger signal parameters can be preset. The PET system generates a trigger signal according to the trigger signal parameters and adds the trigger signal to the input signal of the PET detector, so that the trigger signal and the input signal are input into the PET detector together.

[0049] Figure 2 A schematic diagram of a PET system is provided. The PET system includes a PET detector, a signal generator, and a coincidence circuit. Among them, SiPM (Silicon photomultiplier), a preamplifier, and a shaping circuit are located in the PET detector.

[0050] In practical applications, according to Figure 2 , a signal generator can be set in the PET system. The signal generator is connected to the preamplifier of the PET detector. The signal generator generates a periodic pulse signal and inputs it into the preamplifier together with the input signal of the PET detector.

[0051] Step S120: Determine the delayed coincidence event of the trigger signal in the output signal of the PET detector.

[0052] Among them, the delayed coincidence event can be an event that matches the trigger signal in the output signal waveform.

[0053] In specific implementation, since the trigger signal and the input signal are input into the PET detector together, there is a waveform corresponding to the trigger signal in the output signal of the PET detector. This waveform passes through the electronics module of the PET detector and usually has a certain delay. Therefore, this kind of waveform corresponding to the trigger signal can be called the delayed coincidence event of the trigger signal. The PET system can search for this kind of delayed coincidence event of the trigger signal in the output signal of the PET detector.

[0054] In practical applications, a coincidence circuit can also be provided in the PET system. The coincidence circuit is connected to both the signal generator and the output terminals of the PET detectors. The PET detectors can input the output signals into the coincidence circuit. The coincidence circuit can also obtain the trigger signals generated by the signal generator at the same time. The coincidence circuit performs time-delay coincidence on the output signals of the PET detectors according to the trigger signals, and determines whether there is a delayed waveform of the trigger signal in the current output signals. If there is, the delayed waveform is determined as a time-delay coincidence event. Otherwise, if not, it continues to determine whether there is a delayed waveform of the trigger signal in the subsequent output signals.

[0055] Step S130: Determine the dead time correction factor of the PET detectors according to the number of events of the time-delay coincidence events.

[0056] In specific implementation, the PET system can count the number of time-delay coincidence events, and obtain the dead time correction factor of the PET detectors according to the obtained number of events and the number of pulses of the corresponding trigger signals.

[0057] In practical applications, within the current scan time, the PET system can count the number of time-delay coincidence events n rt , and the number of pulses n rt0 in the trigger signals. The dead time correction factor ε dtc can be

[0058]

[0059] Step S140: Perform dead time correction on the PET detectors according to the dead time correction factor.

[0060] In specific implementation, the PET system can use the dead time correction factor to perform dead time correction on the input signals of the PET detectors in the current scan.

[0061] In practical applications, within the current scan time, the PET system can obtain the actual count n real of the output signals of the PET detectors, and perform dead time correction on the actual count according to n ideal = n real / ε dtc to obtain the corrected count n ideal .

[0062] The above PET detector dead time correction method adds a preset trigger signal to the input signal of the PET detector, determines the delayed coincidence events of the trigger signal in the output signal of the PET detector, determines the dead time correction factor of the PET detector according to the number of delayed coincidence events, and corrects the dead time of the PET detector according to the dead time correction factor; it can add a known trigger signal to the input signal of the PET detector in real time, and obtain the dead time correction factor of the current scan by measuring the number of delayed coincidence events in the detector output signal. Since the dead time correction factor does not need to be determined according to the DTC correction table, the accuracy is relatively high, and the error of dead time correction can be reduced.

[0063] In one embodiment, step S120 above may specifically include: delaying the logic signal corresponding to the trigger signal to obtain a delayed signal of the logic signal; extracting the delayed coincidence events of the trigger signal from the output signal according to the delayed signal.

[0064] Among them, the logic signal may be a signal containing 0 and 1, where 0 represents a low level and 1 represents a high level pulse signal.

[0065] In specific implementation, when the PET system determines the delayed coincidence events, the signal generator may send the logic signal corresponding to the trigger signal to the coincidence circuit, and the coincidence circuit delays the received logic signal so that the obtained delayed signal matches the trigger waveform of the trigger signal in the output signal of the PET detector. Then, the delayed coincidence events can be extracted from the output signal of the PET detector according to the delayed signal.

[0066] Figure 3 A schematic diagram of the delayed coincidence events is provided. According to Figure 3 , assuming that the logic signal contains n rt0 trigger pulses, delaying the logic signal by t to obtain a delayed signal containing n rt0 trigger pulses, screening the delayed coincidence events from the output signal according to the delayed signal, and extracting the trigger waveforms corresponding to n rt (n rt <n rt0 ) trigger pulses from the output signal. Each trigger waveform corresponds to a delayed coincidence event, and n rt delayed coincidence events are obtained.

[0067] In this embodiment, by delaying the logic signal corresponding to the trigger signal to obtain a delayed signal of the logic signal, and extracting the delayed coincidence events of the trigger signal from the output signal according to the delayed signal, the delayed coincidence events can be extracted from the output signal of the PET detector by using the trigger signal, and the dead time correction factor of the PET detector can be accurately determined.

[0068] In one embodiment, the above step S130 may specifically include: determining the number of trigger signals according to the logic signal corresponding to the trigger signal; obtaining the dead time correction factor of the PET detector according to the ratio of the number of events of the delay coincidence event to the number of trigger signals.

[0069] In a specific implementation, the PET system may count the number of trigger signals and the number of events of the delay coincidence event, and determine the ratio of the number of events of the delay coincidence event to the number of trigger signals as the dead time correction factor of the PET detector.

[0070] For example, according to Figure 3 , the dead time correction factor can be obtained

[0071]

[0072] In this embodiment, by determining the number of trigger signals according to the logic signal corresponding to the trigger signal and obtaining the dead time correction factor of the PET detector according to the ratio of the number of events of the delay coincidence event to the number of trigger signals, it is possible to obtain a relatively accurate dead time correction factor without determining the dead time correction factor according to the DTC correction table, thereby reducing the dead time correction error.

[0073] In one embodiment, the above step S140 may specifically include: obtaining the number of corrected signals corresponding to the number of output signals according to the ratio of the output signal to the dead time correction factor.

[0074] Wherein, the number of corrected signals may be the number of output signals after dead time correction.

[0075] In a specific implementation, the PET system may count the actual count of the output signals of the PET detector, that is, the number of output signals, and calculate the ratio of the actual count to the dead time correction factor to obtain the number of corrected signals.

[0076] For example, according to Figure 3 , the PET system can obtain the actual count n of the output signals of the PET detector rral , according to n iodeal =n real / ε dtc perform dead time correction on to obtain the corrected count n ideal of the output signal, and use n ideal as the number of corrected signals.

[0077] In this embodiment, by obtaining the number of corrected signals corresponding to the number of output signals according to the ratio of the output signal to the dead time correction factor, dead time correction can be performed on the output signals of the PET detector, avoiding the SUV value of the generated PET image being lower than the actual value.

[0078] In one embodiment, as Figure 4 shown, a dead time correction system for a PET detector is provided, including a signal generator 202 and a correction module 204; the signal generator 202 is connected to the preamplifier of the PET detector; wherein, the signal generator 202 is configured to generate a preset trigger signal and input the trigger signal into the preamplifier; the preamplifier adds the trigger signal to the input signal of the PET detector; the correction module 204 is configured to determine the dead time correction factor of the PET detector according to the number of events of the delayed coincidence event of the trigger signal, and perform dead time correction on the PET detector according to the dead time correction factor.

[0079] Among them, the signal generator can be a generator of pulse signals. The correction module can be a circuit module capable of performing dead time correction.

[0080] In specific implementation, the signal generator can generate a trigger signal according to preset trigger signal parameters, input the trigger signal into the preamplifier of the PET detector, superimpose it with the input signal of the PET detector to obtain a superimposed signal of the trigger signal and the input signal, input the superimposed signal into the coincidence module through the shaping circuit of the PET detector, the coincidence module screens the delayed coincidence events from the superimposed signal according to the trigger signal of the signal generator, inputs the selected delayed coincidence events into the correction module, and the correction module obtains the dead time correction factor according to the ratio of the number of events of the coincidence event to the number of signals of the trigger signal, and performs dead time correction on the PET detector by using the dead time correction factor.

[0081] The above dead time correction system for a PET detector generates a preset trigger signal, inputs the trigger signal into the preamplifier, the preamplifier adds the trigger signal to the input signal of the PET detector, determines the dead time correction factor of the PET detector according to the number of events of the delayed coincidence event of the trigger signal, and performs dead time correction on the PET detector according to the dead time correction factor; it can add a known trigger signal to the input signal of the PET detector in real time, obtain the dead time correction factor of the current scan by measuring the number of delayed coincidence events in the detector output signal. Since the dead time correction factor does not need to be determined according to the DTC correction table, the accuracy is relatively high, and the error of dead time correction can be reduced.

[0082] In one embodiment, the above-mentioned PET detector dead time correction system further includes a coincidence module 206, and the coincidence module 206 is connected to both the signal generator 202 and the correction module 204; the signal generator 202 is further configured to send the logic signal corresponding to the trigger signal to the coincidence module 206; the coincidence module 206 is configured to perform a delay process on the logic signal, extract the delayed coincidence event of the trigger signal from the output signal of the PET detector according to the obtained delayed signal of the logic signal, and send the delayed coincidence event to the correction module.

[0083] Among them, the coincidence module can be a circuit module capable of performing delayed coincidence processing.

[0084] In specific implementation, the signal generator can send the logic signal corresponding to the trigger signal to the coincidence module, and the coincidence module delays the received logic signal so that the obtained delayed signal matches the trigger waveform of the trigger signal in the output signal of the PET detector. Then, the delayed coincidence event can be extracted from the output signal of the PET detector according to the delayed signal and input to the correction module.

[0085] In this embodiment, by sending the logic signal corresponding to the trigger signal to the coincidence module, the coincidence module performs a delay process on the logic signal, extracts the delayed coincidence event of the trigger signal from the output signal of the PET detector according to the obtained delayed signal of the logic signal, and sends the delayed coincidence event to the correction module; the delayed coincidence event can be extracted from the output signal of the PET detector by using the trigger signal, and the dead time correction factor of the PET detector can be accurately determined.

[0086] In one embodiment, the above-mentioned coincidence module 206 is further configured to determine the signal quantity of the trigger signal according to the logic signal and send the signal quantity to the correction module 204; the correction module 204 is further configured to obtain the dead time correction factor of the PET detector according to the ratio of the event quantity of the delayed coincidence event to the signal quantity, and perform dead time correction on the output signal according to the dead time correction factor to obtain the corrected signal quantity corresponding to the number of output signals.

[0087] In specific implementation, the coincidence module can count the signal quantity of the trigger signal and send it to the correction module. The correction module calculates the ratio of the event quantity of the delayed coincidence event to the signal quantity of the trigger signal to obtain the dead time correction factor. When performing dead time correction, the corrected signal quantity can be obtained according to the ratio of the actual count of the output signal of the PET detector to the dead time correction factor.

[0088] In this embodiment, by determining the number of trigger signals according to the logic signal, obtaining the dead time correction factor of the PET detector based on the ratio of the number of events of the delay coincidence event to the number of signals, and performing dead time correction on the output signal according to the dead time correction factor, the number of corrected signals corresponding to the number of output signals is obtained; dead time correction can be performed on the output signal of the PET detector to prevent the SUV value of the generated PET image from being lower than the actual value.

[0089] In one embodiment, as Figure 5 shown, a PET system is provided, including a PET detector 302 and a PET detector dead time correction system 304; wherein, the PET detector dead time correction system 304 performs the PET detector dead time correction method described in any one of the foregoing embodiments.

[0090] In a specific implementation, the signal generator of the PET detector dead time correction system can generate a trigger signal according to preset trigger signal parameters, input the trigger signal into the preamplifier of the PET detector, superimpose it with the input signal of the PET detector to obtain a superimposed signal of the trigger signal and the input signal, input the superimposed signal into the coincidence module through the shaping circuit of the PET detector, the coincidence module screens delay coincidence events from the superimposed signal according to the trigger signal of the signal generator, inputs the selected delay coincidence events into the correction module, and the correction module obtains the dead time correction factor according to the ratio of the number of events of the coincidence event to the number of signals of the trigger signal, and performs dead time correction on the PET detector by using the dead time correction factor.

[0091] Since the specific processing method of the PET detector dead time correction system has been described in detail in the foregoing embodiments, it will not be elaborated here.

[0092] In the above PET system, by adding a preset trigger signal to the input signal of the PET detector, determining the delay coincidence events of the trigger signal in the output signal of the PET detector, determining the dead time correction factor of the PET detector according to the number of events of the delay coincidence event, and performing dead time correction on the PET detector according to the dead time correction factor; a known trigger signal can be added to the input signal of the PET detector in real time, and the dead time correction factor of the current scan can be obtained by measuring the number of delay coincidence events in the detector output signal. Since the dead time correction factor does not need to be determined according to the DTC correction table, the accuracy is relatively high, and the error of dead time correction can be reduced.

[0093] To facilitate those skilled in the art to deeply understand the embodiments of the present application, a specific example will be described below.

[0094] In one embodiment, a dead time correction method is provided as follows:

[0095] The purpose of local dead time correction is to correct the error between the ideal single count rate and the measured single count rate on a single event and module basis. Traditional dead time correction models include non-paralyzable models, paralyzable models, and combined models of paralyzable and non-paralyzable models. Among them, the combined model can be:

[0096]

[0097] n = n0e -λt +n b

[0098] where m is the actual single event count rate, n is the ideal single event count rate, α and β are dead time coefficients, n b is the background single event count rate, n0 is the ideal initial single event count rate, and λ is the decay constant. When the background n b is much smaller than n0e -λt , the background can be ignored. Combining the above formulas, we can get

[0099]

[0100] me λt = n0 + n0αm + n0βm 2

[0101] At this point, me λt is fitted to a cubic model of m. By solving the fitting coefficients, α and β can be obtained. The final dead time factor is

[0102]

[0103] This application proposes a random trigger-based PET dead time correction method that does not depend on the single event count rate and the DTC correction table. It can inject a waveform similar to the 511 keV signal into the preamplifier of the PET detector through a signal generator at regular intervals (for example, 1 millisecond). This signal is random relative to the physical signal and can be called a random trigger (RT) signal. The RT signal will be collected and processed by subsequent electronics modules, and its dead time effect is the same as that of the real physical signal. Therefore, the ratio of the number of RT signal events finally collected by the electronics module during the PET scan time to the number of RT signal events actually emitted by the signal generator is the live time factor of the detector. After conversion, the dead time correction factor of the detector can be obtained. This dead time correction method eliminates the dependence on the single event count rate for dead time correction, is not affected by the system state, and can obtain a more accurate dead time correction factor. Theoretically, it is not necessary to conduct a radioactive source experiment to obtain the DTC table.

[0104] ReferenceFigure 2 , an RT signal can be injected into the preamplifier of the PET detector by a signal generator every 1 millisecond, and the RT signal will be collected and processed by subsequent electronics modules; meanwhile, the signal generator will simultaneously emit a logic signal as a flag, and perform a time delay coincidence between the flag signal and the output signal of the electronics module to determine whether the current signal is an RT signal, and count the number of RT signals output by the detector electronics module, then the dead time correction factor of the detector can be calculated. The specific formula is

[0105]

[0106] where n rt0 is the number of RT signals emitted by the signal generator during this scanning time, and n rt is the number of RT signals collected at the output end of the electronics module.

[0107] It should be noted that physical signals can also coincide with the flag signal, resulting in misjudgment of RT signals. However, since a single detector module collects a physical signal on average every dozens of microseconds, this situation can be ignored.

[0108] The above PET dead time correction method based on random triggering injects a random trigger signal into the preamplifier of the PET detector, and obtains the dead time correction factor by statistically calculating the ratio of the number of random trigger signals collected at the end of the electronics module to the true value. This dead time factor is closer to the theoretical value and represents the dead time correction factor for the current scan. The change of the system state has little impact on its accuracy. In addition, this method does not require a radioactive source experiment to obtain a DTC correction table.

[0109] It should be understood that although the steps in the flowcharts involved in the above embodiments are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear indication in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily executed at the same moment, but can be executed at different moments. The execution order of these steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least a part of other steps or steps or stages in other steps.

[0110] Based on the same inventive concept, an embodiment of the present application further provides a PET detector dead time correction device for implementing the above-mentioned PET detector dead time correction method. The solution provided by this device to solve the problem is similar to the solution described in the above method. Therefore, the specific limitations in one or more embodiments of the PET detector dead time correction device provided below can refer to the limitations on the PET detector dead time correction method in the above text, and will not be repeated here.

[0111] In one embodiment, as Figure 6 shown, a PET detector dead time correction device is provided, including: a signal addition module 410, an event determination module 420, a factor determination module 430, and a target correction module 440, where:

[0112] The signal addition module 410 is configured to add a pre-set trigger signal to the input signal of the PET detector;

[0113] The event determination module 420 is configured to determine the delay coincidence event of the trigger signal in the output signal of the PET detector;

[0114] The factor determination module 430 is configured to determine the dead time correction factor of the PET detector according to the number of events of the delay coincidence event;

[0115] The target correction module 440 is configured to perform dead time correction on the PET detector according to the dead time correction factor.

[0116] In one embodiment, the above-mentioned event determination module 420 is further configured to perform a delay process on the logic signal corresponding to the trigger signal to obtain a delayed signal of the logic signal; and extract the delay coincidence event of the trigger signal from the output signal according to the delayed signal.

[0117] In one embodiment, the above-mentioned factor determination module 430 is further configured to determine the number of signals of the trigger signal according to the logic signal corresponding to the trigger signal; and obtain the dead time correction factor of the PET detector according to the ratio of the number of events of the delay coincidence event to the number of signals of the trigger signal.

[0118] In one embodiment, the above-mentioned target correction module 440 is further configured to obtain the number of corrected signals corresponding to the number of output signals according to the ratio of the output signal to the dead time correction factor.

[0119] Each module in the above PET detector dead time correction device can be implemented in whole or in part by software, hardware, or a combination thereof. Each of the above modules can be embedded in the processor of a computer device in hardware form or independent thereof, or stored in the memory of the computer device in software form, so as to facilitate the processor to call and execute the operations corresponding to each of the above modules.

[0120] In one embodiment, a computer device is provided. The computer device can be a terminal, and its internal structure diagram can be as Figure 7 shown. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit, and an input device. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface, the display unit, and the input device are connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used for exchanging information between the processor and external devices. The communication interface of the computer device is used for communicating with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a mobile cellular network, NFC (Near Field Communication), or other technologies. The computer program, when executed by the processor, implements a PET detector dead time correction method. The display unit of the computer device is used to form a visually visible picture, which can be a display screen, a projection device, or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen. The input device of the computer device can be a touch layer covering the display screen, or a button, a trackball, or a touchpad provided on the housing of the computer device, or an external keyboard, a touchpad, or a mouse, etc.

[0121] Those skilled in the art can understand that Figure 7 the structure shown in

[0122] is only a block diagram of a part of the structure related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have a different component layout.

[0123] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the steps in the foregoing method embodiments are implemented.

[0124] In one embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in the foregoing method embodiments are implemented.

[0125] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data that have been authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with the relevant laws, regulations, and standards of relevant countries and regions.

[0126] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, data processing logics based on quantum computing, etc., without limitation.

[0127] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0128] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. A method for correcting the dead time of a PET detector, characterized in that, The method includes: Adding a pre-set trigger signal to the input signal of the PET detector; Determining the delayed coincidence events of the trigger signal in the output signal of the PET detector; Determining the dead time correction factor of the PET detector according to the number of events of the delayed coincidence events; Performing dead time correction on the PET detector according to the dead time correction factor.

2. The method according to claim 1, characterized in that, The determining the delayed coincidence events of the trigger signal in the output signal of the PET detector includes: Performing a delay process on the logic signal corresponding to the trigger signal to obtain a delayed signal of the logic signal; Extracting the delayed coincidence events of the trigger signal from the output signal according to the delayed signal.

3. The method according to claim 2, characterized in that, The determining the dead time correction factor of the PET detector according to the number of events of the delayed coincidence events includes: Determining the number of signals of the trigger signal according to the logic signal corresponding to the trigger signal; Obtaining the dead time correction factor of the PET detector according to the ratio of the number of events of the delayed coincidence events to the number of signals of the trigger signal.

4. The method according to claim 1, characterized in that, The performing dead time correction on the PET detector according to the dead time correction factor includes: Obtaining the number of corrected signals corresponding to the number of the output signals according to the ratio of the output signal to the dead time correction factor.

5. A system for correcting the dead time of a PET detector, characterized in that, The system includes a signal generator and a correction module; the signal generator is connected to the preamplifier of the PET detector; The signal generator is configured to generate a pre-set trigger signal, input the trigger signal into the preamplifier; the preamplifier adds the trigger signal to the input signal of the PET detector; The correction module is configured to determine the dead time correction factor of the PET detector according to the number of events of the delayed coincidence events of the trigger signal, and perform dead time correction on the PET detector according to the dead time correction factor.

6. The system according to claim 5, characterized in that, The system further includes a coincidence module, and the coincidence module is connected to both the signal generator and the correction module; The signal generator is further configured to send the logic signal corresponding to the trigger signal to the coincidence module; The coincidence module is configured to perform a delay process on the logic signal, extract the delayed coincidence events of the trigger signal from the output signal of the PET detector according to the obtained delayed signal of the logic signal, and send the delayed coincidence events to the correction module.

7. The system according to claim 6, characterized in that, The coincidence module is further configured to determine the number of signals of the trigger signal according to the logic signal, and send the number of signals to the correction module; The correction module is further configured to obtain the dead time correction factor of the PET detector according to the ratio of the number of events of the delayed coincidence events to the number of signals, and perform dead time correction on the output signal according to the dead time correction factor to obtain the number of corrected signals corresponding to the number of the output signals.

8. A PET system, characterized in that, The system includes a PET detector and the PET detector dead time correction system according to any one of claims 5 to 7.

9. A computer device, including a memory and a processor, the memory stores a computer program, characterized in that, When the processor executes the computer program, the steps of the method according to any one of claims 1 to 4 are implemented.

10. A computer-readable storage medium, on which a computer program is stored, characterized in that, When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 4 are implemented.

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