Pet detector dead time correction method, system, and pet system

Abstract

The application relates to a PET detector dead time correction method, a 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 an output signal of the PET detector; determining a 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. The method can reduce the dead time correction error of the PET detector.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of signal processing, in particular to a PET detector dead time correction method, system and PET system. BACKGROUND

[0002] During processing signals, the detector module of a PET (Positron Emission Tomography) system cannot respond to the next signal received in the current time period, so that the signal recorded by the electronic module is less than the signal detected by the detector, which is called dead time effect. The dead time effect causes the SUV (Standard Uptake Value) of the generated image to be lower than the actual value.

[0003] At present, the dead time correction factor is usually determined based on the single event count rate given by the detector module and the DTC (Dead Time Correction) table obtained from the radiation source experiment. However, since the electronic module of the detector performs step-by-step screening on the signal, the single event count rates corresponding to different electronic modules are not the same, and the final single event count rate is difficult to represent the count rate of the entire detector, resulting in a large error in the dead time correction.

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

[0005] Therefore, it is necessary to provide a dead time correction method, system, device, computer equipment, computer readable storage medium, computer program product and PET system capable of reducing error in view of the above technical problems.

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

[0007] adding a pre-set trigger signal to an input signal of a PET detector;

[0008] determining a delay coincidence event of the trigger signal in an output signal of the PET detector;

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

[0010] correcting the dead time of the PET detector according to the dead time correction factor.

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

[0012] delay the logic signal corresponding to the trigger signal to obtain a delay signal of the logic signal;

[0013] extract the delay coincidence event of the trigger signal from the output signal according to the delay signal.

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

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

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

[0017] In one embodiment, the dead time correction of the PET detector according to the dead time correction factor comprises:

[0018] 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.

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

[0020] The signal generator is configured to generate a pre-set trigger signal and input the trigger signal into the preamplifier; the preamplifier adds the trigger signal into an input signal of the PET detector.

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

[0022] In one embodiment, the system further comprises a coincidence module, which is connected with the signal generator and the correction module.

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

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

[0025] In one of the embodiments, the coincidence module is further configured to determine a signal number of the trigger signal according to the logic signal, and send the signal number to the correction module.

[0026] The correction module is further configured to obtain a dead-time correction factor of the PET detector according to a ratio of the event number of the delay coincidence event and the signal number, perform dead-time correction on the output signal according to the dead-time correction factor, and obtain a corrected signal number corresponding to the number of the output signal.

[0027] In a third aspect, the present application provides a PET detector dead-time correction device.

[0028] The signal adding module is configured to add a preset trigger signal to an input signal of a PET detector.

[0029] The event determining module is configured to determine a delay coincidence event of the trigger signal in an output signal of the PET detector.

[0030] The factor determining module is configured to determine a dead-time correction factor of the PET detector according to an event number of the delay coincidence event.

[0031] The target correction module is 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 provides a computer device. The computer device comprises a memory and a processor, the memory stores a computer program, and the processor implements the dead-time correction method according to any one of the first aspect when executing the computer program.

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

[0034] In a sixth aspect, the present application provides a computer program product. The computer program product comprises a computer program, and the computer program is executed by a processor to implement the dead-time correction method according to any one of the first aspect.

[0035] In a seventh aspect, the present application provides a PET system. The system comprises a PET detector and the PET detector dead time correction system of any one of the second aspect.

[0036] The PET detector dead time correction method, system, device, computer device, storage medium, computer program product and PET system can add the 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 the delay coincidence events in the output signal of the detector, and the dead time correction factor does not need to be determined according to the DTC correction table, so that the accuracy is higher and the error of the dead time correction can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 FIG. 1 is a flowchart of a PET detector dead time correction method according to an embodiment of the present application;

[0038] Figure 2 FIG. 1 is a flowchart of a PET detector dead time correction method according to an embodiment of the present application;

[0039] Figure 3 FIG. 1 is a flowchart of a PET detector dead time correction method according to an embodiment of the present application;

[0040] Figure 4 FIG. 1 is a flowchart of a PET detector dead time correction method according to an embodiment of the present application;

[0041] Figure 5 FIG. 1 is a flowchart of a PET detector dead time correction method according to an embodiment of the present application;

[0042] Figure 6 FIG. 1 is a flowchart of a PET detector dead time correction method according to an embodiment of the present application;

[0043] Figure 7 FIG. 1 is a flowchart of a PET detector dead time correction method according to an embodiment of the present application; DETAILED DESCRIPTION

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

[0045] In one embodiment, as shown in FIG. 1, the PET detector dead time correction method comprises the following steps. Figure 1As shown, a PET detector dead time correction method is provided, and the embodiment takes the method applied to a PET system as an example, and includes the following steps:

[0046] In step S110, a preset trigger signal is added to the input signal of the PET detector.

[0047] The trigger signal can be a pulse signal generated by a signal generator.

[0048] In a specific implementation, in order to determine the dead time correction factor of the PET detector, the trigger signal parameters can be preset, the PET system generates the 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 is input to the PET detector together with the input signal.

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

[0050] In actual application, according to Figure 2 The signal generator can be arranged in the PET system, and the signal generator is connected to the preamplifier of the PET detector, and the signal generator generates a periodic pulse signal, which is input to the preamplifier together with the input signal of the PET detector.

[0051] In step S120, a delay coincidence event of the trigger signal is determined in the output signal of the PET detector.

[0052] The delay coincidence event can be an event in the output signal waveform that matches the trigger signal.

[0053] In a specific implementation, since the trigger signal is input to the PET detector together with the input signal, there is a waveform corresponding to the trigger signal in the output signal of the PET detector, and the waveform passes through the electronics module of the PET detector, and there is usually a certain delay, so the waveform corresponding to the trigger signal can be referred to as a delay coincidence event of the trigger signal, and the PET system can search for such a delay coincidence event of the trigger signal in the output signal of the PET detector.

[0054] In practical applications, the PET system can be further provided with a coincidence circuit, the coincidence circuit is connected with the signal generator and the output end of the PET detector, the PET detector can input the output signal to the coincidence circuit, the coincidence circuit can also obtain the trigger signal generated by the signal generator, and the output signal of the PET detector is delayed according to the trigger signal, whether the delayed waveform of the trigger signal exists in the current output signal is judged, if the delayed waveform exists, the delayed waveform is determined as a delay coincidence event, otherwise, if the delayed waveform does not exist, whether the delayed waveform of the trigger signal exists in the following output signal is judged.

[0055] In step S130, the dead time correction factor of the PET detector is determined according to the number of delay coincidence events.

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

[0057] In practical applications, the PET system can count the number of delay coincidence events n rt and the number of pulses n rt0 of the trigger signal within the current scanning time, and the dead time correction factor ε dtc may be

[0058]

[0059] In step S140, the dead time of the PET detector is corrected according to the dead time correction factor.

[0060] In specific implementation, the PET system can use the dead time correction factor to correct the input signal of the PET detector in the current scanning.

[0061] In practical applications, the PET system can obtain the actual count n real of the output signal of the PET detector within the current scanning time, correct the actual count according to n ideal =n real / ε dtc , and obtain the corrected count n ideal of the output signal.

[0062] The PET detector dead time correction method adds the preset trigger signal to the input signal of the PET detector, determines the delay coincidence event 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 the delay coincidence events, and corrects the dead time of the PET detector according to the dead time correction factor. The known trigger signal can be added to the input signal of the PET detector in real time, the number of delay coincidence events in the output signal of the detector is measured to obtain the dead time correction factor of the current scan, the dead time correction factor does not need to be determined according to the DTC correction table, the accuracy is high, and the error of the dead time correction can be reduced.

[0063] In one embodiment, the step S120 can specifically include: delaying the logic signal corresponding to the trigger signal to obtain a delay signal of the logic signal; and extracting the delay coincidence event of the trigger signal from the output signal according to the delay signal.

[0064] The logic signal can be a signal containing 0 and 1, where 0 represents a low level and 1 represents a high level pulse signal.

[0065] In a specific implementation, when determining the delay coincidence event, the signal generator can send the logic signal corresponding to the trigger signal to the coincidence circuit, the coincidence circuit delays the received logic signal, so that the obtained delay signal matches the trigger waveform of the trigger signal in the output signal of the PET detector, and then the delay coincidence event can be extracted from the output signal of the PET detector according to the delay signal.

[0066] Figure 3 A schematic diagram of a delay coincidence event is provided. According to Figure 3 , it is assumed that the logic signal contains n rt0 trigger pulses, the logic signal is delayed by t to obtain a delay signal containing n rt0 trigger pulses, the delay coincidence event is screened from the output signal according to the delay signal, and n rt (n rt <n rt0 ) trigger pulses corresponding to the trigger waveform are extracted from the output signal, each trigger waveform corresponds to a delay coincidence event, and n rt delay coincidence events are obtained.

[0067] In this embodiment, the logic signal corresponding to the trigger signal is delayed to obtain a delay signal of the logic signal, and the delay coincidence event of the trigger signal is extracted from the output signal according to the delay signal. The delay 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.

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

[0069] In practice, the PET system can count the number of trigger signals and the number of delayed coincidence events. The ratio of the number of delayed coincidence events to the number of trigger signals is used 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, the number of trigger signals is determined based on the logic signals corresponding to the trigger signals; the dead time correction factor of the PET detector is obtained based on the ratio of the number of delayed coincidence events to the number of trigger signals. This eliminates the need to determine the dead time correction factor based on the DTC correction table, resulting in a more accurate dead time correction factor and thus reducing dead time correction error.

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

[0074] The number of corrected signals can be the number of output signals after dead-time correction.

[0075] In practice, the PET system can count the actual number of output signals of the PET detector, that is, the number of output signals, calculate the ratio of the actual count to the dead time correction factor, and 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 signal from the PET detector. rral According to n iodeal =n real / ε dtc Dead time correction is performed to obtain the corrected count n of the output signal. ideal , will n ideal As the number of corrected signals.

[0077] In the embodiment, the number of corrected signals corresponding to the number of output signals is obtained according to the ratio of the output signal and the dead time correction factor, the dead time correction of the PET detector output signal is performed, and the SUV value of the generated PET image is prevented from being lower than the actual value.

[0078] In one embodiment, as shown in Figure 4 A PET detector dead time correction system is provided, including a signal generator 202 and a correction module 204; the signal generator 202 is connected to a preamplifier of a PET detector; wherein the signal generator 202 is configured to generate a pre-set trigger signal and input the trigger signal to the preamplifier; the preamplifier adds the trigger signal to the input signal of the PET detector; the correction module 204 is configured to determine a dead time correction factor of the PET detector according to the number of events of the delayed coincidence events of the trigger signal, and correct the dead time of the PET detector according to the dead time correction factor.

[0079] The signal generator can be a pulse signal generator. The correction module can be a circuit module capable of dead time correction.

[0080] In a specific implementation, the signal generator can generate a trigger signal according to a pre-set trigger signal parameter, input the trigger signal to the preamplifier of the PET detector, superimpose the trigger signal on the input signal of the PET detector, obtain a superposition signal of the trigger signal and the input signal, input the superposition signal to a coincidence module through a shaping circuit of the PET detector, filter the delayed coincidence events from the superposition signal according to the trigger signal of the signal generator, input the filtered delayed coincidence events to the correction module, obtain a dead time correction factor according to the ratio of the number of events of the coincidence events and the number of signals of the trigger signal, and correct the dead time of the PET detector by using the dead time correction factor.

[0081] The PET detector dead time correction system generates a pre-set trigger signal, inputs the trigger signal to the preamplifier, adds the trigger signal to the input signal of the PET detector, determines a dead time correction factor of the PET detector according to the number of events of the delayed coincidence events of the trigger signal, and corrects the dead time of the PET detector according to the dead time correction factor; the known trigger signal can be added to the input signal of the PET detector in real time, the number of delayed coincidence events in the detector output signal is measured to obtain the dead time correction factor of the current scan, the dead time correction factor does not need to be determined according to the DTC correction table, the accuracy is high, and the error of the dead time correction can be reduced.

[0082] In one embodiment, the PET detector dead time correction system described above further comprises a coincidence module 206 connected with 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 delay processing on the logic signal, extract the delay coincidence event of the trigger signal from the output signal of the PET detector according to the delay signal of the logic signal, and send the delay coincidence event to the correction module.

[0083] In the specific implementation, the coincidence module can be a circuit module capable of delay coincidence processing.

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

[0085] In the embodiment, the logic signal corresponding to the trigger signal is sent to the coincidence module, the coincidence module performs delay processing on the logic signal, extracts the delay coincidence event of the trigger signal from the output signal of the PET detector according to the delay signal of the logic signal, and sends the delay coincidence event to the correction module; the delay coincidence event can be extracted from the output signal of the PET detector using the trigger signal, and the dead time correction factor of the PET detector can be accurately determined.

[0086] In one embodiment, the coincidence module 206 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 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 number of events of the delay coincidence event to the number of signals, perform dead time correction on the output signal according to the dead time correction factor, and obtain the number of corrected signals corresponding to the number of output signals.

[0087] In the specific implementation, the coincidence module can count the number of signals of the trigger signal and send it to the correction module, the correction module calculates the ratio of the number of events of the delay coincidence event to the number of signals of the trigger signal to obtain the dead time correction factor, and when performing dead time correction, the number of corrected signals 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 the embodiment, the dead time correction factor of the PET detector is obtained according to the ratio of the event quantity of the delay coincidence event to the signal quantity of the trigger signal according to the logical signal, the output signal is corrected according to the dead time correction factor, and the corrected signal quantity corresponding to the output signal quantity is obtained; the dead time correction of the PET detector output signal can be performed, and the SUV value of the generated PET image is prevented from being lower than the actual value.

[0089] In one embodiment, as shown in Figure 5 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 in any one of the preceding embodiments.

[0090] In a specific implementation, the signal generator of the PET detector dead time correction system can generate a trigger signal according to a pre-set trigger signal parameter, input the trigger signal to a preamplifier of the PET detector, superimpose the trigger signal on an input signal of the PET detector to obtain a superimposed signal of the trigger signal and the input signal, input the superimposed signal to a coincidence module through a shaping circuit of the PET detector, filter delay coincidence events from the superimposed signal according to the trigger signal of the signal generator, input the filtered delay coincidence events to a correction module, obtain a dead time correction factor according to the ratio of the event quantity of the delay coincidence event to the signal quantity of the trigger signal, and correct the dead time of 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 preceding embodiments, it will not be described here.

[0092] The PET system described above adds a pre-set trigger signal to an input signal of the PET detector, determines delay coincidence events of the trigger signal in an output signal of the PET detector, determines a dead time correction factor of the PET detector according to the event quantity of the delay coincidence event, and corrects the dead time of 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, the quantity of the delay coincidence events in the detector output signal is measured to obtain the dead time correction factor of the current scan, the dead time correction factor does not need to be determined according to a DTC correction table, the accuracy is high, and the error of the dead time correction can be reduced.

[0093] In order to facilitate those skilled in the art to have a further understanding of the embodiments of the present application, the following will be described in conjunction with a specific example.

[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 ideal single count rate and measured single count rate on the basis of single event and module. The traditional dead-time correction model includes non-paralysis model, paralysis model, and combined model of paralysis model and non-paralysis model. 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, and a and b are dead-time coefficients. n b is the background single event count rate, n0 is the ideal initial single event count rate, and l is the decay constant. When the background n b is much smaller than n0e -λt , the background can be ignored. According to the above formula, we can get

[0099]

[0100] me λt = n0 + n0a m + n0b m 2

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

[0102]

[0103] The application proposes a PET dead-time correction method based on random trigger, which does not depend on single event count rate and DTC correction table. A signal generator can inject a waveform similar to a 511 keV signal to the preamplifier of a PET detector every certain period of time (for example, 1 millisecond). The 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 the subsequent electronic module, and its dead-time effect is the same as that of the real physical signal. Therefore, the ratio of the number of RT signal cases finally collected by the electronic module to the number of RT signal cases actually emitted by the signal generator during the PET scanning time 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 of dead-time correction on single event count rate and is not affected by system state, which can obtain more accurate dead-time correction factor and theoretically does not need to perform radioactive source experiment to obtain DTC table.

[0104] ReferenceFigure 2 The RT signal can be injected into the preamplifier of the PET detector by the signal generator every 1 ms, and the RT signal can be collected and processed by the subsequent electronic module. At the same time, the signal generator will send a logic signal as a flag at the same time. The flag signal and the output signal of the electronic module are delayed to match, to determine whether the current signal is an RT signal. The number of RT signals output by the detector electronic module is counted, and the dead time correction factor of the detector can be calculated. The specific formula is

[0105]

[0106] Wherein, n rt0 is the number of RT signals sent by the signal generator in the scanning time, and n rt is the number of RT signals collected at the output end of the electronic module.

[0107] It should be noted that the physical signal can also match the flag signal, causing misjudgment of the RT signal. However, since a single detector module collects a physical signal for an average of tens of microseconds, this case can be ignored.

[0108] The above PET dead time correction method based on random triggering injects a random triggering signal into the preamplifier of the PET detector, counts the ratio of the number of random triggering signals collected at the end of the electronic module to the true value, and obtains the dead time correction factor. The dead time factor is closer to the theoretical value, representing the dead time correction factor of the next scan, and the system state change has little effect on its accuracy. In addition, this method also does not need to perform a radioactive source experiment to obtain a DTC correction table.

[0109] It should be understood that although each step in the flowchart involved in each embodiment as described above is displayed in sequence according to the arrow, these steps are not necessarily executed in sequence according to the arrow. Unless otherwise stated herein, the execution of these steps is not strictly limited in sequence, and these steps can be executed in other orders. Moreover, at least part of the steps in the flowchart involved in each embodiment as described above can include multiple steps or stages, which are not necessarily executed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be executed in rotation or alternation with at least part of other steps or steps or stages in other steps.

[0110] Based on the same inventive concept, the embodiments of the present application also provide a PET detector dead time correction device for implementing the PET detector dead time correction method described above. The implementation scheme of the device for solving the problem is similar to the implementation scheme described in the above method, so the specific limitations in one or more PET detector dead time correction device embodiments provided below can refer to the limitations of the PET detector dead time correction method in the foregoing, which will not be repeated here.

[0111] In one embodiment, as shown in Figure 6 A PET detector dead time correction device is provided, comprising: a signal adding module 410, an event determining module 420, a factor determining module 430, and a target correction module 440, wherein:

[0112] The signal adding module 410 is configured to add a preset trigger signal to an input signal of a PET detector.

[0113] The event determining module 420 is configured to determine a delayed coincidence event of the trigger signal in an output signal of the PET detector.

[0114] The factor determining module 430 is configured to determine a dead time correction factor of the PET detector according to an event number of the delayed 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 event determining module 420 described above is further configured to perform delay processing on a logical signal corresponding to the trigger signal to obtain a delayed signal of the logical signal, and extract the delayed coincidence event of the trigger signal from the output signal according to the delayed signal.

[0117] In one embodiment, the factor determining module 430 described above is further configured to determine a signal number of the trigger signal according to a logical signal corresponding to the trigger signal, and obtain the dead time correction factor of the PET detector according to a ratio of the event number of the delayed coincidence event to the signal number of the trigger signal.

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

[0119] The modules in the PET detector dead time correction device can be implemented by software, hardware, or a combination thereof. The modules can be embedded in or independent of a processor in a computer device in hardware form, or stored in a memory in the computer device in software form, so that the processor can call and execute the operations corresponding to the modules.

[0120] In one embodiment, a computer device, which can be a terminal, has an internal structure as shown in Figure 7 The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit, and an input device. 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. The processor of the computer device is configured 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 running the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is configured to exchange information between the processor and external devices. The communication interface of the computer device is configured to perform wired or wireless communication with external terminals. The wireless communication can be achieved through WIFI, mobile cellular network, NFC (Near Field Communication), or other technologies. The computer program is executed by the processor to implement a PET detector dead time correction method. The display unit of the computer device is configured 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 overlaid on the display screen, or a key, trackball, or touchpad arranged on the housing of the computer device, or an external keyboard, touchpad, or mouse, etc.

[0121] Those skilled in the art can understand that Figure 7 The structure shown in the above embodiment is only a block diagram of part of the structure related to the scheme of the present application, and does not limit the computer device to which the scheme of the present application is applied. The specific computer device can include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0122] In one embodiment, a computer device is also provided, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps in the above method embodiments.

[0123] In an embodiment, a computer readable storage medium is provided, and the computer readable storage medium has stored thereon a computer program which, when executed by a processor, implements the steps of any of the above method embodiments.

[0124] In an embodiment, a computer program product is provided, and the computer program product comprises a computer program which, when executed by a processor, implements the steps of any of the above method embodiments.

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

[0126] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium, and when the computer program is executed, the processes of the above-mentioned embodiments of the methods can be included. Any reference to memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (Read-Only Memory, ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive memory (ReRAM), magnetoresistive random access memory (Magnetoresistive Random Access Memory, MRAM), ferroelectric memory (Ferroelectric Random Access Memory, FRAM), phase change memory (Phase Change Memory, PCM), graphene memory, etc. Volatile memory can include random access memory (Random Access Memory, RAM) or external cache memory, etc. As an illustration but not limitation, RAM can be in various forms, such as static random access memory (Static Random Access Memory, SRAM) or dynamic random access memory (Dynamic Random Access Memory, DRAM), etc. The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a block chain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., without being limited thereto.

[0127] Any combination of the technical features of the above embodiments can be made. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0128] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of protection of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A PET detector dead-time correction method, characterized by, The method comprises: adding a preset trigger signal to an input signal of a PET detector; determining a time-delay coincidence event of the trigger signal in an output signal of the PET detector, further comprising: time-delaying a received logical signal to make a time-delayed signal match a trigger waveform in the output signal; determining a dead-time correction factor of the PET detector according to a ratio of a number of the time-delay coincidence events to a number of the trigger signals; correcting a dead time of the PET detector according to the dead-time correction factor.

2. The method of claim 1, wherein, The determining of the time-delay coincidence event of the trigger signal in the output signal of the PET detector comprises: time-delaying a logical signal corresponding to the trigger signal to obtain a time-delayed signal of the logical signal; extracting the time-delay coincidence event of the trigger signal from the output signal according to the time-delayed signal.

3. The method of claim 2, wherein, Before the determining of the dead-time correction factor of the PET detector according to the ratio of the number of the time-delay coincidence events to the number of the trigger signals, the method further comprises: determining the number of the trigger signals according to the logical signal corresponding to the trigger signal.

4. The method of claim 1, wherein, The correcting of the dead time of the PET detector according to the dead-time correction factor comprises: obtaining a number of corrected signals corresponding to a number of the output signals according to a ratio of the output signal to the dead-time correction factor.

5. A PET detector dead time correction system, characterized by, The system comprises a signal generator, a coincidence module and a correction module; the signal generator is connected with a preamplifier of a PET detector, the coincidence module is connected with the signal generator and the correction module; the signal generator is configured to generate a preset trigger signal, and input the trigger signal to the preamplifier, so that the preamplifier adds the trigger signal to an input signal of the PET detector; the coincidence module is configured to determine a time-delay coincidence event of the trigger signal in an output signal of the PET detector, further comprising: time-delaying a received logical signal to make a time-delayed signal match a trigger waveform in the output signal; the correction module is configured to determine a dead-time correction factor of the PET detector according to a ratio of a number of the time-delay coincidence events to a number of the trigger signals, and correct a dead time of the PET detector according to the dead-time correction factor.

6. The system of claim 5, wherein, The signal generator is further configured to send a logical signal corresponding to the trigger signal to the coincidence module; the coincidence module is further configured to time-delay the logical signal, extract a time-delay coincidence event of the trigger signal from an output signal of the PET detector according to a time-delayed signal of the logical signal, and send the time-delay coincidence event to the correction module.

7. The system of claim 6, wherein, The coincidence module is further configured to determine the number of the trigger signals according to the logical signal, and send the number of the trigger signals to the correction module.

8. A PET system characterized by, The system comprises a PET detector and a PET detector dead-time correction system according to any one of claims 5 to 7. 9.A computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the computer device is configured to perform the method according to any one of claims 1-8 when the computer program is executed by the processor. The computer program is executed by the processor to implement the steps of the method of any one of claims 1 to 4.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the method of any one of claims 1 to 4.

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