CN102631212B - PET (positron emission tomography) scanner and meeting wherein sentence choosing method - Google Patents

Abstract

The invention relates to a positron emission tomography scanner and a coincidence selection method therein. The scanner includes a plurality of detectors, and the method includes: obtaining case information of each detector; storing each case information in a corresponding storage space, and using the time information of each case information as address information of the storage space; Obtain a plurality of flag information, each flag information indicates the number of gamma photons detected in the corresponding time information; according to each flag information to obtain the selection information, each selection information represents starting from the corresponding time information, within the preset time window The number of gamma photons detected within; sort the judging information according to the corresponding time information; use the sequence check feature to check the sorted judging information in turn to determine the storage space corresponding to the case; output the matching case Instance information in the corresponding storage space. The invention has the advantages of fast, high efficiency and wide application range.

Description

Positron emission tomography scanner and coincidence selection method therein

technical field

The invention relates to the field of nuclear medicine imaging, in particular to a positron emission tomography (PET) scanner and a coincidence selection method therein.

Background technique

The purpose of PET is to image and determine the position of the emitting positron nuclide, so as to obtain the distribution of tracer drugs in the body and achieve the purpose of diagnosing diseases such as tumors. However, PET does not directly detect positrons, but reflects the position of positron nuclides by detecting 511 KeV gamma photon pairs generated by electron pair annihilation. The connection line between the two detector crystal strips that received the two gamma photons is called the line of response (Line of Response, LOR), which represents the straight line where the gamma photon pair flying in the opposite direction is located, and the position of the annihilation event is at on this straight line. The method of using the connection line between two detector crystal strips to determine the position of the annihilation point is called electron collimation, and this detection method is called coincidence detection.

Figure 1 shows an existing detection ring 9 for detecting gamma photons, the detection ring 9 is made up of a plurality of modules (such as 16 modules 12a-12p in Fig. Block 7, each block 7 is composed of strip crystals 6 (dimensions, eg 1.9mm×1.9mm×10mm) in an array (eg 16×16 array). As shown in FIG. 2 , 2a and 2b represent two gamma photons with equal energy and opposite directions generated by positron annihilation, which may be detected by two detectors 12a and 12e respectively.

Fig. 3 shows that according to different fields of view (Field Of View, FOV) (as shown in dotted lines 11a, 11b in Fig. 2), the coincidence judgment among the detectors is carried out, and the coincidence detection between the detectors is represented by the response line 10.

The coincidence detection technology utilizes two properties of photon pairs: one is that the two photons fly along a straight line; the other is that they both travel forward at the speed of light and arrive at the two detectors on the straight line almost at the same time. But in fact, due to the uncertainty principle in physics and the measurement error of the instrument itself, it is difficult for two gamma photons from the same annihilation event to be detected strictly at the same time. Generally, there is a time interval. The interval is called the coincidence time window, which is generally between a few nanoseconds and tens of nanoseconds. Only the combination of a pair of 511 KeV gamma photons detected within the coincident time window is called a coincident event. As shown in Figure 4, where 4a and 4b represent the time t1 and t2 when the two gamma photons 2a and 2b in Figure 1 arrive at the detectors 12a and 12e respectively, if the difference between t1 and t2 is less than the preset time window 5, then The two gamma photons 2a and 2b are considered to be produced by the same annihilation event.

It can be seen that the selection of matching cases is the key to determine the location of the vanishing point. An existing matching selection method is: first sort a batch of loaded data according to time, and then compare the time difference of adjacent data to see if they are in the same position. If it is within the matching time window, then carry out spatial matching to determine whether it is within the field of view (Field Of View, FOV). If so, then pack and transmit the data as a matching case to the back-end computer for image reconstruction.

The method's conformity judgment idea is intuitive and easy to think about. But the disadvantages are: when the amount of data involved in matching is large at the same time, it becomes difficult to sort in the field-programmable gate array (Field-Programmable GateArray, FPGA), consumes a lot of resources, takes a long clock cycle, and is difficult to implement in actual projects. implemented in the application. Therefore, this method is feasible when there are few front-end detector modules such as small animal PET or breast-specific PET, and there are few matching data. However, in human PET, the detector modules are multiplied, and the above method is not feasible.

Contents of the invention

A brief overview of the invention is given below in order to provide a basic understanding of some aspects of the invention. It should be understood that this summary is not an exhaustive overview of the invention. It is not intended to identify key or critical parts of the invention nor to delineate the scope of the invention. Its purpose is merely to present some concepts in a simplified form as a prelude to the more detailed description that is discussed later.

A main purpose of the present invention is to overcome the defects of the traditional coincidence selection method, and provide a fast, efficient, and widely applicable positron emission tomography scanner and a coincidence selection method therein.

In order to achieve the above object, the present invention provides a method for judging coincidence in a positron emission tomography scanner. Options include:

Acquiring the case information of each detector, each case information includes the time information of the corresponding detector detecting the gamma photon, the position information of the corresponding detector and the energy information of the corresponding detector;

storing each case information in the corresponding storage space in sequence according to its time information, and using the time information of each case information as the address information of the corresponding storage space, wherein there is a fixed value difference between adjacent time information;

Obtain a plurality of flag information according to the instance information in each of the storage spaces, and store the acquired flag information into a plurality of flag registers corresponding to each of the time information, and each of the flag information is represented by the corresponding time information. The number of gamma photons detected;

Obtain the selection information according to each flag information, and store the obtained selection information in multiple selection registers corresponding to each time information, each selection information represents detection within the preset matching time window starting from the corresponding time information to the number of gamma photons;

Sorting each judging information according to the corresponding time information;

Use N sequence check features to check the sorted selection information in order to determine the storage space corresponding to the occurrence of coincidence cases. The coincidence cases refer to the detection of gamma photons twice and only twice within the preset coincidence time, where "N" is the number of time information contained in the matching time window, and the N sequence inspection features are: when the time interval between two single cases in the matching case is 0, 1...N-1, sorting The distribution characteristics in the final selection information; and

Output the case information in the storage space corresponding to the matching case that occurred.

To achieve the above object, the present invention also provides a positron emission tomography scanner, comprising:

Multiple detectors for detecting gamma photons produced by positron nuclear annihilation;

The receiving module is used to obtain the case information of each detector, and the case information includes the time information of the corresponding detector detecting the gamma photon, the position information of the corresponding detector and the corresponding energy information of the detector;

The storage control module is used to store each case information in the corresponding storage space according to its time information sequence, and the time information in each case information is used as the address information of the corresponding storage space, wherein there is a fixed value between adjacent time information Difference;

The first analysis module is used to obtain a plurality of flag information according to the instance information in each of the storage spaces, and store each flag information in a plurality of flag registers corresponding to each of the time information, and each of the flag information is represented in The number of gamma photons detected by the corresponding time information;

The second analysis module is configured to generate a plurality of selection information according to each of the flag information, and store each of the selection information in a plurality of selection registers corresponding to each of the time information, and each of the selection information Represents the number of gamma photons detected within the preset coincident time window starting from the corresponding time information;

A sorting module, configured to sort each judging information according to the corresponding time information;

The feature inspection module uses N sequence inspection features to check the sorted selection information in order to determine the storage space corresponding to the occurrence of matching cases. A matching case means that there are only two detections within the preset matching time γ photons, where "N" is the number of time information contained in the matching time window, and the N sequence inspection features are: the time interval between two single cases in the matching case is 0, 1...N-1 The distribution characteristics of cases in the sorted selection information; and

The output module is used to output the case information in the storage space corresponding to the coincident case that occurs.

The positron emission tomography scanner of the present invention and its coincidence selection method store the time information in the case information of each detector as the address information of the storage space by means of "time-space conversion", and use the flag information to generate a representative coincidence time The selection information of the cases in the window, and check the selection information according to the sequence inspection characteristics to find the storage space corresponding to the case, and output the case information in this space for image reconstruction, avoiding the traditional method The problem of large amount of data processing and slow speed makes it also applicable to human PET with a large number of detectors, achieving the purpose of fast, efficient and wide application range.

Description of drawings

The above and other objects, features and advantages of the present invention will be more easily understood with reference to the following description of the embodiments of the present invention in conjunction with the accompanying drawings. The components in the drawings are only to illustrate the principles of the invention. In the drawings, the same or similar technical features or components will be denoted by the same or similar reference numerals.

Fig. 1 is a schematic structural diagram of a detection ring in the prior art.

Figure 2 is a schematic diagram of two gamma photons with equal energy and opposite directions being detected by two detectors respectively.

FIG. 3 is a schematic diagram of matching selection between detectors according to different field of view ranges in the prior art.

Fig. 4 is a time sequence diagram of two gamma photons with equal energy and opposite direction respectively detected by two detectors.

Fig. 5 is a schematic structural diagram of a detector in an embodiment of the present invention.

Fig. 6 is a schematic structural diagram of a positron emission tomography scanner according to an embodiment of the present invention.

FIG. 7 is an example diagram of a part of flag registers, judging registers, and judging information generated according to flag information in FIG. 6 .

FIG. 8 is an example diagram of sorted selection information.

Figures 9A-9F are respectively the judgment information obtained when the time interval of detecting a single event is 0 nanoseconds, 1 nanoseconds, 2 nanoseconds, 3 nanoseconds, 4 nanoseconds and 5 nanoseconds within the matching time window Example plot of the distribution.

FIG. 10 is a flow chart of a coincidence judging method of a positron emission tomography scanner in an example of the present invention.

Detailed ways

Embodiments of the present invention will be described below with reference to the drawings. Elements and features described in one drawing or one embodiment of the present invention may be combined with elements and features shown in one or more other drawings or embodiments. It should be noted that representation and description of components and processes that are not related to the present invention and known to those of ordinary skill in the art are omitted from the drawings and descriptions for the purpose of clarity.

An embodiment of the present invention provides a method for coincidence discrimination in a positron emission tomography scanner. The positron emission tomography scanner includes a plurality of detectors for detecting gamma photons generated by the annihilation of positron nuclei, and for coincidence discrimination. Methods include:

Acquiring the case information of each detector, each case information includes the time information of the corresponding detector detecting the gamma photon, the position information of the corresponding detector and the energy information of the corresponding detector;

storing each case information in the corresponding storage space in sequence according to its time information, and using the time information of each case information as the address information of the corresponding storage space, wherein there is a fixed value difference between adjacent time information;

Obtain a plurality of flag information according to the event information in each storage space, and store the acquired flag information into a plurality of flag registers corresponding to each time information, each flag information indicates the number of gamma photons detected at the corresponding time information ;

Obtain the selection information according to each flag information, and store the obtained selection information in multiple selection registers corresponding to each time information, each selection information represents detection within the preset matching time window starting from the corresponding time information to the number of gamma photons;

Sorting each judging information according to the corresponding time information;

Use N sequence check features to check the sorted selection information in order to determine the storage space corresponding to the occurrence of coincidence cases. The coincidence cases refer to the detection of gamma photons twice and only twice within the preset coincidence time, where "N" is the number of time information contained in the matching time window, and the N sequence inspection features are: when the time interval between two single cases in the matching case is 0, 1...N-1, sorting The distribution characteristics in the final selection information; and

Output the case information in the storage space corresponding to the matching case that occurred.

Optionally, each case information is represented by a binary value with a preset bit width, and each flag information is 2-bit data, wherein, when each flag information is "00", "01", "10" or "11", it represents The corresponding time information is "no gamma photon detected", "gamma photon detected once", "gamma photon detected twice" or "gamma photon detected more than twice".

Optionally, each selection information is 2-bit data, wherein each selection information is the lowest two bits of data after adding the values of N consecutive flag registers starting from the corresponding flag register.

Optionally, when the time interval between two single cases in the matching case is n unit time intervals, the sequence checking feature in the sorted judgment information is: consecutive N+n values are not "00" and "11 "In the data, there are 2n data with the value of "01" and consecutive N-n data with the value of "10". Among them, the 2n data with the value of "01" are symmetrically distributed among the consecutive N-n data with the value of "10". On both sides of the data, n is any integer greater than or equal to 0 and less than or equal to N-1.

Optionally, sequentially checking the sorted selection information by using the N sequence checking features is performed in a parallel processing manner.

Optionally, each case information is stored in the storage space of the dual-port random access memory, and the time information of each case information is the address of the dual-port random access memory, and each address of the dual-port random access memory stores two Case information with the same time information.

Embodiments of the present invention also provide a positron emission tomography scanner, comprising:

Multiple detectors for detecting gamma photons produced by positron nuclear annihilation;

The receiving module is used to obtain the case information of each detector, and the case information includes the time information of the corresponding detector detecting the gamma photon, the position information of the corresponding detector and the corresponding energy information of the detector;

The storage control module is used to store each case information in the corresponding storage space according to its time information sequence, and the time information in each case information is used as the address information of the corresponding storage space, wherein there is a fixed value between adjacent time information Difference;

The first analysis module is used to obtain a plurality of flag information according to the instance information in each of the storage spaces, and store each flag information in a plurality of flag registers corresponding to each of the time information, and each of the flag information is represented in The number of gamma photons detected by the corresponding time information;

The second analysis module is configured to generate a plurality of selection information according to each of the flag information, and store each of the selection information in a plurality of selection registers corresponding to each of the time information, and each of the selection information Represents the number of gamma photons detected within the preset coincident time window starting from the corresponding time information;

A sorting module, configured to sort each judging information according to the corresponding time information;

The feature inspection module uses N sequence inspection features to check the sorted selection information in order to determine the storage space corresponding to the occurrence of matching cases. A matching case means that there are only two detections within the preset matching time γ photons, where "N" is the number of time information contained in the matching time window, and the N sequence inspection features are: the time interval between two single cases in the matching case is 0, 1...N-1 The distribution characteristics of cases in the sorted selection information; and

The output module is used to output the case information in the storage space corresponding to the coincident case that occurs.

Optionally, each case information is represented by a binary value with a preset bit width, and each flag information is 2-bit data, wherein, when each flag information is "00", "01", "10" or "11", it represents The corresponding time information is "no gamma photon detected", "gamma photon detected once", "gamma photon detected twice" or "gamma photon detected more than twice".

Optionally, each selection information is 2-bit data, wherein each selection information is the lowest two bits of data after adding the values of N consecutive flag registers starting from the corresponding flag register.

Optionally, when the time interval between two single cases in the matching case is n unit time intervals, the sequence checking feature in the sorted judgment information is: consecutive N+n values are not "00" and "11 "In the data, there are 2n data with the value of "01" and consecutive N-n data with the value of "10". Among them, the 2n data with the value of "01" are symmetrically distributed among the consecutive N-n data with the value of "10". On both sides of the data, n is any integer greater than or equal to 0 and less than or equal to N-1.

Optionally, the feature inspection module uses N sequence inspection features to sequentially inspect the sorted selection information through parallel processing.

Optionally, each case information is stored in the storage space of the dual-port random access memory, and the time information of each case information is the address of the dual-port random access memory, and each address of the dual-port random access memory stores two Case information with the same time information.

Embodiments of the present invention will be specifically introduced below in conjunction with the accompanying drawings.

Referring to Fig. 5 to Fig. 7, the present invention provides a positron emission tomography scanner, one embodiment of which includes a plurality of detectors, for example in Fig. 5, 32 detectors 0-31 encircle a circular regular polygon The detection ring 10. Each detector is used to detect gamma photons produced by electron pair annihilation, and a single gamma photon produced by electron pair annihilation is called a single event.

As shown in Figure 6, in an embodiment of the present invention, the positron emission tomography scanner also includes a receiving module 41, a storage control module 42, a first analysis module 43, a second analysis module 44, a sorting module 45, a feature Check module 46 and output module 47 .

Wherein, the receiving module 41 is used to acquire the case information of each detector, and the case information includes the time information of the gamma photons detected by the corresponding detectors.

Each case information may also include position information of the corresponding detector, for example, the position of the detector in the detection ring 10 .

Each case information may also include energy information of a corresponding detector.

For example, each case information includes a binary value with a bit width of 32, the lower 7 bits of the case information store time information, and other bits store position information and energy information, or other necessary data. The time represented by the lowest bit is 1 nanosecond, and the time range that can be represented by 7 bits is 128 nanoseconds.

In this embodiment, more than one (for example, two) detections may be performed on the same time information to obtain more than one instance information corresponding to the same time information. For example, a dual-port RAM (random access memory) can be set. The depth of the dual-port RAM is 128, and the width is 64. The case information of each 32-bit width is stored in the storage space of the dual-port RAM. The time information is used as the address information of the dual-port RAM, and each address information can store two 32-bit wide instance information, that is to say, the time information of the two instance information stored on each address information of the dual-port RAM is the same , which means the case information obtained by detection at the same time.

The storage control module 42 is used to store each case information in the corresponding storage space in sequence according to its time information, and the time information in each case information is used as the address information of the corresponding storage space, wherein there is a fixed value between adjacent time information The difference is, for example, 1 nanosecond, that is to say, what the receiving module 41 acquires is the event information obtained by detecting every 1 nanosecond.

Fig. 7 shows an example of part of the flag register FlagXX, the judgment register Trig_regXX and the generation of judgment information according to the flag information. Each flag register is set corresponding to the time information (such as 1 nanosecond-128 nanoseconds) in each case information, that is, it is set corresponding to the address information of each storage space, and each flag register is used to store the first analysis module 43 according to the A plurality of flag information acquired by the event information in each storage space, each flag information is 2-bit data, used to indicate the number of gamma photons detected by the corresponding detector in the corresponding time information. For example, when the event information indicates that the corresponding detector has not detected gamma photons in its time information, the corresponding flag information is "00"; when the event information indicates that the corresponding detector has detected γ photons once in its time information For γ photons, the corresponding flag information is "01"; when the event information indicates that the corresponding detector detects γ photons twice in its time information, the corresponding flag information is "10"; when the event information indicates When the corresponding detector detects gamma photons more than twice in its time information, the corresponding flag information is "11".

Each selection register corresponds to the time information of each case information, and is used to store the selection information generated by the second analysis module 44 according to each flag information. The number of detected gamma photons.

Specifically, for example, when the preset matching time window is 6 nanoseconds, each selection information is the lowest two bits of data after adding the values (flag information) of 6 consecutive flag registers starting from the corresponding flag register.

The sorting module 45 is configured to sort the selection information according to the corresponding time information, for example, to obtain the sorted selection information as shown in FIG. 8 .

When the time interval between two single cases in the matching case is n unit time intervals, the sequence checking feature in the sorted judgment information is: in the data with consecutive N+n values other than "00" and "11" , with 2n data with the value "01" and consecutive N-n data with the value "10", where the 2n data with the value "01" are symmetrically distributed on both sides of the continuous N-n data with the value "10" , n is any integer greater than or equal to 0 and less than or equal to N-1.

Specifically, when the time interval between two single cases in a matching case is 0, the sequence checking feature in the sorted judgment information is: consecutive N data whose values are not "00" and "11", including consecutive N data with a value of "10";

When the time interval between two single cases in a matching case is 1, the sequence inspection feature in the sorted selection information is: consecutive N+1 data whose values are not "00" and "11", among which consecutive N- 1 data with a value of "10" is distributed between 2 data with a value of "01";

...

When the time interval between two single cases in the matching case is N-1, the sequence inspection feature in the sorted judgment information is: consecutive N+(N-1) values are not "00" and "11" , where 1 data with a value of "10" is distributed in the middle, and 2×(N-1) data with a value of "01" are evenly distributed on both sides.

For example, Figures 9A-9F respectively show that the time intervals for detecting single events are 0 nanoseconds (n=0) within the coincident time window (that is, gamma photons are detected at the same time), 1 nanoseconds (n=1), 1 nanoseconds (n=1), The distribution of the judgment information obtained at 2 nanoseconds (n=2), 3 nanoseconds (n=3), 4 nanoseconds (n=4) and 5 nanoseconds (n=5), where "T" Indicates the sequence checking features for the above 6 cases. In this embodiment, the sequence check features in the above six cases are:

One, 101010101010, that is, consecutive N+n values that are not "00" and "11" (at this time, N=6, which is the number of time information in the time window, n=0), including consecutive N values that are " 10" value, 0(2n) "01" values. .

Two, 011001010101001, that is, consecutive N+1 (6+1) values that are not "00" and "11", among which N-1 consecutive values that are "10" are distributed in the middle, and two "01" values distributed on both sides.

Three, 0101101010100101, that is, consecutive N+2 (6+2) values that are not "00" and "11", of which N-2 consecutive values that are "10" are distributed in the middle, and 4 "01" values evenly distributed on both sides.

Four, 010101101010010101, that is, N+3 (6+3) consecutive values that are not "00" and "11", of which N-3 consecutive values that are "10" are distributed in the middle, and 6 "01" values evenly distributed on both sides.

Five, 01010101101001010101, that is, N+4 (6+4) consecutive values that are not "00" and "11", among which N-4 consecutive values that are "10" are distributed in the middle, and 8 "01" values Evenly distributed on both sides.

Six, 0101010101100101010101, that is, N+(N-1)(6+5) consecutive values that are not "00" and "11", among which the value of 1 "10" is distributed in the middle, and the value of 10 "01" is averaged distributed on both sides.

Within the coincident time window, if the sorted selection information has a distribution that conforms to the above sequence inspection characteristics, it can be determined that a coincident event has occurred, and the case information corresponding to the occurred coincident event can be determined.

The feature inspection module 46 uses N (in this embodiment, N=6) sequence inspection features to check the sorted selection information in turn, for example, starting from the lowest bit, the sorted selection information and each sequence inspection feature For comparison, when a distribution identical to any sequence inspection feature is found in the sorted selection information, the address information of the storage space corresponding to the distribution, that is, the time information, is determined to find the instance in the storage space The information is output to the back-end computer via the output module 47 for image reconstruction.

Take the second sequence check feature as an example, use the shift counter to start the same distribution as the sequence check feature from the lowest 14-bit value, whether the 14-bit value is "01101010101001" and if so, then according to the distribution in the sorted The position in the judging information finds the corresponding flag register, determines the time information corresponding to the flag register, and outputs the case information stored in the storage space with the time information as the address information; and shifts the shift register to the high position by 14 Bits continue to be compared until all voting information has been scanned.

Referring to FIG. 10 , the present invention provides a method for judging coincidence in the above-mentioned positron emission tomography scanner, and one embodiment thereof includes:

Step S1: The receiving module 41 obtains the case information of each detector, wherein each case information includes the time information of the corresponding detector detecting the γ photon, the position information of the corresponding detector and the energy information of the corresponding detector. Each event information is represented by a binary value. For example, each event information can be 32-bit wide binary data, of which the lower 7 bits are used to store its time information, and the other bits are used to store position information and energy information or other required data. Specifically, for example, the 32 data acquisition boards at the front end of the detectors 0-31 can collect the information on the corresponding detectors, perform analog-to-digital conversion and digital integration on the collected information, and then receive it by the receiving module 41 .

Step S2: The storage control module 42 stores each case information in the corresponding storage space in sequence according to its time information, and the time information of each case information is used as the address information of the corresponding storage space, wherein there are fixed values between adjacent time information Difference. The value difference is the interval time for detecting gamma photons, for example, 1 nanosecond.

Optionally, in step S2, the storage control module 42 stores each case information in the storage space of the dual-port RAM, and the time information of each case information is used as the address of the dual-port RAM, and each address of the dual-port RAM stores two Case information with the same time information.

Step S3: Obtain a plurality of flag information according to the instance information in each storage space, and store the acquired flag information into a plurality of flag registers corresponding to each time information. In step S3, each flag information indicates the number of gamma photons detected at the corresponding time information.

Optionally, each flag information is 2-bit data, such as "00", "01", "10" or "11".

Step S4: Acquire the selection information according to each flag information, and store the obtained selection information in multiple selection registers corresponding to each time information, each selection information represents starting from the corresponding time information, at the preset matching time The number of gamma photons detected within the window.

Optionally, the value of each selection information is 2-bit data, and the value of each selection information is the lowest two bits of data after adding the values of N consecutive flag registers starting from the corresponding flag register.

Step S5: The sorting module 45 sorts each judging information according to the corresponding time information.

Step S6: The feature checking module 46 checks the sorted selection information sequentially by using N sequence checking features, so as to determine the storage space corresponding to the occurrence of matching cases. Wherein, a coincidence event means that there are only two gamma photons detected within the preset coincidence time, and "N" is the number of time information included in the coincidence time window.

For example, when the preset coincidence time window is 6 nanoseconds, the time interval between two single cases detected within the time window is 0 nanoseconds, 1 nanosecond...or 5 nanoseconds. The N sequence checking features are respectively the distribution features in the sorted selection information when the time interval between two single cases in the matching case is 0, 1...N-1.

Optionally, in step S6, the feature inspection module 46 uses N sequence inspection features to sequentially check the sorted judgment information through parallel processing, that is, the sorted judgment information can be combined with the sorted judgment information at the same time. N sequences check features for comparison.

Step S7: The output module 47 outputs the case information in the storage space corresponding to the coincident case that occurred.

Optionally, as shown in Figure 8, in step S6, the priority of selecting the matching case can be selected according to the size of the time interval of the two single cases in the matching case, that is, it is preferentially determined that the time interval of the two single cases is close. The storage space corresponding to the matching instance. In step S7, case information may be output according to the set priority.

The positron emission tomography scanner of the present invention and its coincidence selection method store the time information in the case information of each detector as the address information of the storage space by means of "time-space conversion", and use the flag information to generate a representative coincidence time The selection information of the cases in the window, and check the selection information according to the sequence inspection characteristics to find the storage space corresponding to the case, and output the case information in this space for image reconstruction, avoiding the traditional method The problem of large amount of data processing and slow speed makes it also applicable to human PET with a large number of detectors, achieving the purpose of fast, efficient and wide application range.

In the system and method of the present invention, obviously, each component or each step can be decomposed, combined and/or decomposed and then recombined. These decompositions and/or recombinations should be considered equivalents of the present invention. Meanwhile, in the above descriptions of specific embodiments of the present invention, features described and/or shown for one embodiment can be used in one or more other embodiments in the same or similar manner, and combination of features, or replace features in other embodiments.

It should be emphasized that the term "comprising/comprising" when used herein refers to the presence of a feature, element, step or component, but does not exclude the presence or addition of one or more other features, elements, steps or components.

Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made hereto without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present invention is not limited to the specific embodiments of the procedures, devices, means, methods and steps described in the specification. Those of ordinary skill in the art will readily appreciate from the disclosure of the present invention that existing and future devices that perform substantially the same function or obtain substantially the same results as the corresponding embodiments described herein can be used in accordance with the present invention. The developed process, device, means, method or steps. Accordingly, the appended claims are intended to include within their scope such processes, means, means, methods or steps.

Claims (12)

1. A coincident discrimination method in a positron emission tomography scanner, the positron emission tomography scanner comprising a plurality of detectors for detecting the γ photons produced by the annihilation of positron emission tomography, characterized in that the Compliant judging methods include: acquiring event information of each of the detectors, each of the event information includes the time information of the corresponding detector detecting the gamma photon, the position information of the corresponding detector, and the energy information of the corresponding detector; storing each of the case information in the corresponding storage space according to its time information sequence, and using the time information of each of the case information as the address information of the corresponding storage space, wherein there is a fixed value difference between adjacent time information ; Obtain a plurality of flag information according to the instance information in each of the storage spaces, and store the acquired flag information into a plurality of flag registers corresponding to each of the time information, and each of the flag information indicates that detected by the corresponding time information to the number of gamma photons; Obtain selection information according to each of the flag information, and store the acquired selection information in a plurality of selection registers corresponding to each time information, each of the selection information represents starting from the corresponding time information The number of gamma photons detected in the time window; Sorting each of the judging information according to the corresponding time information; Use N sequence check features to check the sorted selection information in order to determine the storage space corresponding to the occurrence of the coincidence case, the coincidence case means that there are only two detections within the preset coincidence time γ photons, where "N" is the number of time information contained in the coincidence time window, and the N sequence inspection features are respectively: the time interval between two single cases in the coincidence cases is 0, 1 ...the distribution characteristics in the sorted selection information in the case of N-1; and Output the case information in the storage space corresponding to the matching case that occurred. 2. the coincidence selection method in the positron emission tomography scanner as claimed in claim 1, is characterized in that, each described event information is represented with the binary value of preset bit width, and each described flag information is 2 bit data , wherein, when each of the flag information is "00", "01", "10" or "11", it represents that at the corresponding time information "gamma photon is not detected", "gamma photon is detected once", " gamma photon detected twice" or "gamma photon detected more than twice". 3. The coincident selection method in the positron emission tomography scanner as claimed in claim 2, wherein each said selection information is 2-bit data, wherein each said selection information is from the corresponding sign The lowest two bits of data after adding the values of N consecutive flag registers at the beginning of the register. 4. The coincident selection method in the positron emission tomography scanner according to any one of claims 1-3, characterized in that, When the time interval between two single cases in the coincident cases is n unit time intervals, the sequence inspection feature in the sorted judgment information is: consecutive N+n values are not "00" and "11" Among the data, there are 2n data with the value "01" and consecutive N-n data with the value "10", among which, the 2n data with the value "01" are symmetrically distributed among the consecutive N-n data with the value "10" On both sides, n is any integer greater than or equal to 0 and less than or equal to N-1. 5. as any one of claim 1-3 described in the positron emission tomography scanner accords with the judging method, it is characterized in that, utilize described N sequence inspection features to check the judging information after sorting successively is through parallel processing. 6. The coincidence selection method in the positron emission tomography scanner according to any one of claims 1-3, wherein each case information is stored in the storage space of a dual-port random access memory, each The time information of the instance information is the address of the dual-port random access memory, and each address of the dual-port random access memory stores two instance information with the same time information. 7. A positron emission tomography scanner, characterized in that, comprising: Multiple detectors for detecting gamma photons produced by positron nuclear annihilation; The receiving module is used to obtain the case information of each detector, the case information includes the time information when the corresponding detector detects the gamma photon, the position information of the corresponding detector and the corresponding energy information of the detector; The storage control module is used to store each case information in the corresponding storage space according to its time information sequence, and the time information in each case information is used as the address information of the corresponding storage space, wherein the time information between adjacent time information have a fixed value difference; The first analysis module is used to obtain a plurality of flag information according to the instance information in each of the storage spaces, and store each flag information in a plurality of flag registers corresponding to each of the time information, and each of the flag information is represented in The number of gamma photons detected by the corresponding time information; The second analysis module is configured to generate a plurality of selection information according to each of the flag information, and store each of the selection information in a plurality of selection registers corresponding to each of the time information, and each of the selection information Represents the number of gamma photons detected within the preset coincident time window starting from the corresponding time information; A sorting module, configured to sort the judging information according to the corresponding time information; The feature inspection module uses N sequence inspection features to check the sorted selection information in order to determine the storage space corresponding to the occurrence of coincidence cases. The coincidence cases refer to the fact that there are and only Gamma photons are detected twice, where "N" is the number of time information contained in the coincidence time window, and the N sequence inspection features are respectively: the time interval between two single cases in the coincidence cases is 0 , the distribution characteristics in the sorted selection information in the case of 1...N-1; and The output module is used to output the case information in the storage space corresponding to the coincident case that occurs. 8. The positron emission tomography scanner according to claim 7, wherein each of the case information is represented by a binary value with a preset bit width, and each of the flag information is 2-bit data, wherein, when each When the above flag information is "00", "01", "10" or "11", it means that the corresponding time information is "no gamma photon detected", "gamma photon detected once", "gamma photon detected twice ” or “More than two gamma photons were detected”. 9. The positron emission tomography scanner as claimed in claim 7, wherein each said selection information is 2-bit data, wherein each said selection information is consecutive N signs starting from the corresponding flag register The lowest two bits of data after the value of the register is added. 10. The positron emission tomography scanner according to any one of claims 7-9, characterized in that, When the time interval between two single cases in the coincident cases is n unit time intervals, the sequence inspection feature in the sorted judgment information is: consecutive N+n values are not "00" and "11" Among the data, there are 2n data with the value "01" and consecutive N-n data with the value "10", among which, the 2n data with the value "01" are symmetrically distributed among the consecutive N-n data with the value "10" On both sides, n is any integer greater than or equal to 0 and less than or equal to N-1. 11. The positron emission tomography scanner according to any one of claims 7-9, wherein the feature inspection module uses the N sequence inspection features to check the sorted selection information sequentially through processed in parallel. 12. The positron emission tomography scanner according to any one of claims 7-9, wherein each of the case information is stored in the storage space of a dual-port random access memory, and the time of each of the case information The information is the address of the dual-port random access memory, and each address of the dual-port random access memory stores two instance information with the same time information.