Nuclear medicine diagnostic equipment

Abstract

To reduce the burden associated with data transfer and storage in nuclear medicine diagnostic equipment. [Solution] The nuclear medicine diagnostic apparatus according to the embodiment comprises a stand device and a console device. The stand device comprises an acquisition unit and a transfer unit. The acquisition unit collects count information of annihilation gamma rays emitted from a subject. The transfer unit transfers the collected count information to the console device. The console device comprises a first storage unit and a coincidence count identification unit. The first storage unit stores the count information transferred from the stand device. The coincidence count identification unit performs a pairing process to identify a combination of two count information corresponding to two annihilation gamma rays emitted in opposing directions from a first group of count information transferred from the stand device, and then deletes the count information outside the specified non-deletion range from the count information of the first group, leaving the count information within the specified non-deletion range to be used for pairing the second group of count information to be transferred from the stand device next.

Description

Technical Field

[0001] The embodiments disclosed in this specification and the drawings relate to nuclear medicine diagnostic devices.

Background Art

[0002] Conventionally, as a nuclear medicine diagnostic device capable of performing functional diagnosis on a living tissue of a subject, a PET (Positron Emission computed Tomography) device (positron tomography device) is known. Also, in a PET device, as the resolution increases, the number of detector arrays tends to increase. In addition, there has also emerged a PET device with a long FOV (Field of view), such as a whole body PET device (or Total Body PET device) that can scan the whole body of a subject without moving the patient bed.

[0003] Generally, in a PET device, data detected by a detector of a gantry device is transferred to a console device and pairing processing is performed. However, since the increase in the number of detectors increases the amount of data to be transferred and paired, the load related to data transfer and storage has been increasing.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] One of the problems that the embodiments disclosed herein and in the drawings aim to solve is to reduce the burden of data transfer and storage in nuclear medicine diagnostic devices. However, the problems that the embodiments disclosed herein and in the drawings aim to solve are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described later can also be positioned as other problems. [Means for solving the problem]

[0006] The nuclear medicine diagnostic apparatus according to this embodiment comprises a stand device and a console device. The stand device comprises an acquisition unit and a transfer unit. The acquisition unit collects count information of annihilation gamma rays emitted from a subject. The transfer unit transfers the collected count information to the console device. The console device comprises a first storage unit and a coincidence count identification unit. The first storage unit stores the count information transferred from the stand device. The coincidence count identification unit performs a pairing process to identify a combination of two count information corresponding to two annihilation gamma rays emitted in opposing directions from a first group of count information transferred from the stand device, and then deletes count information outside a specified non-deletion range from the count information of the first group, leaving count information within a specified non-deletion range to be used for pairing processing of a second group of count information to be transferred from the stand device next. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 shows an example of the configuration of a PET apparatus according to the first embodiment. [Figure 2] Figure 2 shows an example of the data flow of counting information according to the first embodiment. [Figure 3] Figure 3 shows an example of a unit of pairing processing for counting information according to the first embodiment. [Figure 4] Figure 4 is a sequence diagram showing an example of the processing flow according to the first embodiment. [Modes for carrying out the invention]

[0008] The embodiments of the nuclear medicine diagnostic device will be described in detail below with reference to the drawings. In the following embodiments, parts with the same reference numerals perform similar operations, and redundant explanations will be omitted as appropriate.

[0009] Furthermore, for the sake of clarity in the explanation, the nuclear medicine diagnostic device according to this embodiment is assumed to be a PET (Positron Emission Tomography) device. However, the nuclear medicine diagnostic device is not limited to a PET device; it may also be a PET-CT (Computed Tomography) device. Moreover, the nuclear medicine diagnostic device may also be a SPECT (Single Photon Emission Computed Tomography) device.

[0010] (First embodiment) Figure 1 shows an example of the configuration of a PET apparatus 1 according to the first embodiment. As shown in Figure 1, the PET apparatus 1 includes a frame device 10, a bed device 30, and a console device 40.

[0011] In this embodiment, the central axis of the detector 12 or the longitudinal direction of the top plate 33 of the patient bed device 30 is defined as the Z-axis direction, the axis direction perpendicular to the Z-axis direction and horizontal to the floor surface is defined as the X-axis direction, and the axis direction perpendicular to the Z-axis direction and perpendicular to the floor surface is defined as the Y-axis direction. In Figure 1, multiple gantry devices 10 are drawn for illustrative purposes, but in the actual configuration of the PET device 1, there is only one gantry device 10.

[0012] The rigging device 10 includes a Data Acquisition System (DAS) 11 and a detector 12. The detector 12 detects gamma rays (annihilation gamma rays) emitted from a subject P to which a drug labeled with a positron-emitting radioisotope (positron-emitting nuclide) has been administered. In the PET device 1, detecting gamma rays emitted from the subject P is also referred to as scanning the subject P.

[0013] The detector 12 includes a plurality of detector modules 12a arranged in a ring shape around the subject P. The detector 12 is an example of a data collection unit that collects count information of gamma rays emitted from the subject P. The count information includes, for example, the detection location, energy value, and detection time (collection time) of the gamma rays. The detection time may be an absolute time or the elapsed time from the start of the scan.

[0014] The detector module 12a undergoes scintillation and emits light in response to gamma rays emitted from the subject P. The detector module 12a detects the emitted light and converts it into an electrical signal corresponding to its energy. The detector module 12a is composed of, for example, a scintillator array and a SiPM (Silicon-photomultiplier) array. Alternatively, the detector module 12a may be composed of a scintillator array and a PMT (Photomultiplier).

[0015] In the PET scanner 1, the stand unit 10 includes multiple detectors 12. The multiple detectors 12 are arranged along the X-axis. By arranging the detectors 12 in double rows along the X-axis, the FOV (Field of View) in the X-axis direction (the axis direction of the subject P) of the PET scanner 1 is expanded. For example, if the length d of the stand unit 10 in the X-axis direction is approximately 2 meters, the entire body of the subject P can be scanned simultaneously. A PET scanner 1 equipped with a stand unit 10 large enough to simultaneously scan the entire body of the subject P is called a whole-body PET scanner or total-body PET scanner. When the PET scanner 1 is a whole-body PET scanner, the subject P can be scanned without moving the patient table unit 30 along the X-axis. Note that the PET scanner 1 is not limited to a whole-body PET scanner, and may be configured to scan while moving the subject P.

[0016] DAS11 transfers gamma-ray counting information based on the output signal of the detector module 12a to the console device 40. DAS11 is an example of a transfer unit.

[0017] The bed device 30 is a device for placing and moving the subject P to be scanned, and includes a base 31, a bed driving device 32, a top plate 33, and a top plate support frame 34. The base 31 is a housing that supports the top plate support frame 34 so as to be movable in the vertical direction. The bed driving device 32 is a motor or an actuator that moves the top plate 33 on which the subject P is placed in the longitudinal axis direction of the top plate 33. The bed driving device 32 moves the top plate 33 according to the control by the console device 40 or the control by the gantry device 10. The top plate 33 provided on the upper surface of the top plate support frame 34 is a plate on which the subject P is placed. Note that the bed driving device 32 may move the top plate support frame 34 in the longitudinal axis direction of the top plate 33 in addition to the top plate 33. When scanning the subject P, the bed device 30 may move the top plate 33 by the Step&Shoot method that alternately performs scanning and the movement of the top plate 33, or may move the top plate 33 by the bed continuous movement method that moves the top plate 33 while scanning.

[0018] In addition, when the PET device 1 is a whole body PET device, since the subject P can be scanned without moving the bed device 30 as described above, the bed device 30 does not have to move in the Z-axis direction of the top plate 33.

[0019] The console device 40 has a memory 41, a display 42, an input interface 43, and a processing circuit 44. Note that the console device 40 is described as being separate from the gantry device 10, but the gantry device 10 may include the console device 40 or a part of each component of the console device 40.

[0020] The memory 41 is realized by, for example, a semiconductor memory element such as a RAM (Random Access Memory) or a flash memory, a hard disk, an optical disk, or the like. The memory 41 stores, for example, projection data or CT image data. Also, for example, the memory 41 stores programs for the circuits included in the PET apparatus 1 to realize various functions. The memory 41 may be realized by a server group (cloud) connected to the PET apparatus 1 via a network. The memory 41 is an example of a storage unit or a first storage unit.

[0021] The display 42 displays various types of information. For example, the display 42 outputs a medical image (PET image) generated by the processing circuit 44, a GUI (Graphical User Interface) for receiving various operations from the operator, and the like. For example, as the display 42, for example, a liquid crystal display (LCD), an organic EL display (OELD), a plasma display, or any other display can be appropriately used. Also, the display 42 may be provided on the gantry device 10. Also, the display 42 may be a desktop type or may be configured by a tablet terminal or the like capable of wireless communication with the console device 40 main body.

[0022] The input interface 43 receives various input operations from the operator, converts the received input operations into electrical signals, and outputs them to the processing circuit 44. For example, the input interface 43 receives from the operator collection conditions when collecting projection data, reconstruction conditions when reconstructing a CT image, image processing conditions when generating a post-processing image from a CT image, and the like. As the input interface 43, for example, a mouse, a keyboard, a trackball, a switch, a button, a joystick, a touch pad, and a touch panel display can be appropriately used.

[0023] In this embodiment, the input interface 43 is not limited to those equipped with physical operating components such as a mouse, keyboard, trackball, switch, button, joystick, touchpad, and touch panel display. For example, an electrical signal processing circuit that receives an electrical signal corresponding to an input operation from an external input device provided separately from the device and outputs this electrical signal to the processing circuit 44 is also included as an example of the input interface 43. Furthermore, the input interface 43 is an example of an input unit. The input interface 43 may also be provided on the stand device 10. Furthermore, the input interface 43 may consist of a tablet terminal or the like that can communicate wirelessly with the console device 40 main unit. Furthermore, the input interface 43 may also be provided on the stand device 10. Furthermore, the input interface 43 may consist of a tablet terminal or the like that can communicate wirelessly with the console device 40 main unit.

[0024] The processing circuit 44 controls the operation of the entire PET apparatus 1. The processing circuit 44 has, for example, a system control function 441, a coincidence count identification function 442, an image reconstruction function 443, a judgment function 444, and a display control function 445. The system control function 441 is an example of a control unit. The coincidence count identification function 442 is an example of a coincidence count identification unit. The image reconstruction function 443 is an example of image reconstruction. The judgment function 444 is an example of a judgment unit. The display control function 445 is an example of display control. In this embodiment, each processing function performed by the system control function 441, the coincidence count identification function 442, the image reconstruction function 443, the judgment function 444, and the display control function 445 is stored in memory 41 in the form of a program that can be executed by a computer. The processing circuit 44 is a processor that reads the program from memory 41 and executes it to realize the function corresponding to each program. In other words, the processing circuit 44 in the state in which each program has been read has the functions shown in the processing circuit 44 of Figure 1.

[0025] In Figure 1, the system control function 441, the coincidence counting identification function 442, the image reconstruction function 443, the judgment function 444, and the display control function 445 are explained using a single processor. However, the processing circuit 44 may be configured by combining multiple independent processors, with each processor executing a program to realize the functions. Also, in Figure 1, a single memory circuit such as memory 41 is explained as storing programs corresponding to each processing function. However, multiple memory circuits may be distributed and the processing circuit 44 may be configured to read the corresponding programs from individual memory circuits.

[0026] In the above explanation, the term "processor" refers to circuits such as a CPU (Central Processing Unit), a GPU (Graphical Processing Unit), an Application Specific Integrated Circuit (ASIC), or a programmable logic device (e.g., a Simple Programmable Logic Device (SPLD), a Complex Programmable Logic Device (CPLD), and a Field Programmable Gate Array (FPGA)). The processor functions by reading and executing a program stored in memory 41. Alternatively, instead of storing the program in memory 41, the processor may be configured to directly incorporate the program into its circuitry. In this case, the processor functions by reading and executing the program incorporated into the circuitry.

[0027] The system control function 441 controls various functions of the processing circuit 44 based on input operations received from the operator via the input interface 43. The system control function 441 also controls the entire PET apparatus 1 by controlling various parts of the pallet unit 10 and the console unit 40. For example, the system control function 441 controls the bed drive unit 32 to move the tabletop 33. Furthermore, the system control function 441 controls various components of the PET apparatus 1 to perform scans. For example, the system control function 441 controls the detector 12 to collect count information of annihilation gamma rays emitted from the subject P.

[0028] The same counter counting identification function 442 performs a pairing process on the counting information transferred from the stand device 10.

[0029] Here, we will explain the data transfer flow of counting information from the mounting device 10 to the console device 40 using Figure 2. Figure 2 is a diagram showing an example of the data flow according to the first embodiment. Note that the Raw Data, Single Data, and Paired data shown in Figure 2 are all counting information of annihilation gamma rays, but they differ in their data processing state. Details of each data will be explained along with the data transfer flow.

[0030] As shown in Figure 2, the detector 12 includes a memory 121, a processing circuit 122, and a front-end circuit 123. Although Figure 2 shows one detector 12, the mounting device 10 may include multiple detectors 12.

[0031] The memory 121 is implemented by, for example, a semiconductor memory element such as RAM or flash memory. The memory 121 is an example of a storage unit or a second storage unit.

[0032] The processing circuit 122 is, for example, a processor such as an FPGA. The processing circuit 122 may also be an example of a data transfer unit.

[0033] The front-end circuit 123 is a circuit that generates counting information, including the detection location, energy value, and detection time of annihilation gamma rays, based on an electrical signal output from, for example, the detector module 12a. The data generated by the front-end circuit 123 is called raw data. The front-end circuit 123 sends the raw data to the processing circuit 122.

[0034] The processing circuit 122 performs calculations to correct energy information and timing information on the raw data acquired from the front-end circuit 123, and converts it into single data. Single data is also called single event data or single list mode data.

[0035] Here, the annihilation gamma rays collected by the PET device 1 are gamma rays (photons) generated when a positively charged electron (positron) combines with a normally negatively charged electron. These annihilation gamma rays are emitted in directions approximately 180 degrees opposite each other, and their energy is 511 keV (the rest mass energy of an electron). By simultaneously detecting the two annihilation gamma rays emitted in directions approximately 180 degrees opposite each other with separate detector modules 12a, it can be determined that the source AP (shown in Figure 1) lies on a straight line connecting the two detector modules 12a. The line connecting the two detector modules 12a that detected these annihilation gamma rays is called the LOR (Line of Response) (shown in Figure 1).

[0036] Single Data is data in which the pair of annihilation gamma rays emitted from subject P was not identified, and the count information related to the detection of each annihilation gamma ray was recorded as a single event.

[0037] The processing circuit 122 temporarily stores the generated Single Data in the memory 121. The processing circuit 122 also transfers the counting information stored in the memory 121 to the console device 40 at predetermined data size or acquisition time intervals. Although not shown in Figure 2, the Single Data is transferred from the mounting device 10 to the console device 40 via the DAS 11.

[0038] For example, when the Single Data stored in memory 121 reaches a predetermined data size, or when Single Data for a predetermined time length is stored in memory 121, the processing circuit 122 transfers the Single Data stored in memory 121 to the console device 40 as a group. The processing circuit 122 also deletes the counting information that has been transferred to the console device 40 from memory 121. Then, when the Single Data stored in memory 121 again reaches a predetermined data size, or when counting information for a predetermined time length is again stored in memory 121, the processing circuit 122 transfers the Single Data stored in memory 121 to the console device 40 as the next group. In this way, the processing circuit 122 temporarily stores the generated Single Data in memory 121 and then transfers it to the console device 40 in chunks of a certain unit.

[0039] The processing circuit 122 may also sort the Single Data by the detection time contained in the Single Data before transferring it.

[0040] The specified data size and specified time length may be predetermined, for example, according to the processing speed of the processing circuit 44 of the console device 40 and the size of the detector 12 and the console device's memory 41,121. For example, the specified data size and specified time length are determined so that when Single Data is grouped in units of the specified data size or specified time length, one group is of a size that can be processed by the console device 40 and the detector 12. Furthermore, whether the division unit of Single Data is the specified data size or the specified time length may be predetermined or dynamically determined by the determination function 444 of the console device 40.

[0041] Furthermore, the processing circuit 122 does not necessarily have to temporarily save Single Data to memory 121 at all times. It may only temporarily save Single Data to memory 121 when the determination function 444 of the console device 40 determines that temporary saving is necessary. The determination of whether or not temporary saving is necessary may also be made by the processing circuit 122.

[0042] Furthermore, if the processing circuit 122 determines that temporary storage of Single Data is unnecessary, it will not temporarily store the Single Data in memory 121 or divide the Single Data into multiple groups. In this case, the processing circuit 122 will transfer the Single Data to the console device 40 each time it is collected. Even if the Single Data is not stored in memory 121, it may still be stored in buffer memory or the like for transfer processing.

[0043] When Single Data is transferred from the mounting device 10 to the console device 40, the processing circuit 44 of the console device 40 performs a pairing process for the Single Data.

[0044] More specifically, the simultaneous counting identification function 442 of the processing circuit 44 temporarily stores the Single Data transferred from the mounting device 10 in memory 41. The simultaneous counting identification function 442 then generates Paired Data by performing a pairing process on the temporarily stored Single Data. If the Single Data is not sorted within the mounting device 10, the simultaneous counting identification function 442 sorts the Single Data by the detection time contained in the Single Data before performing the pairing process.

[0045] The pairing process identifies a combination of two Single Data points from the Single Data transferred from the mounting device 10 that correspond to two annihilation gamma rays emitted in opposing directions. For example, the coincidence counting identification function 442 pairs each event detected within a predetermined timing window to identify two events detected almost simultaneously. The timing window is also called a time window, time width, or time window. In other words, the coincidence counting identification function 442 generates Paired Data by identifying a combination of two Single Data points from the Single Data transferred from the mounting device 10 whose acquisition times are within a certain timing window width, treating this as information of two annihilation gamma rays counted simultaneously.

[0046] Paired data is data in which two Single Data sets, corresponding to two annihilation gamma rays, are associated as a pair. Paired data is an example of simultaneous counting information.

[0047] The same-count identification function 442 performs sequential pairing for each group of Single Data that has been transferred in multiple groups. Once the pairing process for one group of Single Data is complete, the same-count identification function 442 deletes the processed Single Data from memory 41, except for the range necessary for pairing the next group of Single Data. The range necessary for pairing the next group of Single Data is an example of a defined range that will not be deleted. The pairing process and the deletion of Single Data will be described later using Figure 3.

[0048] Furthermore, if the Single Data is not transferred in multiple groups but is transferred each time it is collected, the same-count identification function 442 stores all the Single Data collected in a single scan in memory 41. After all the Single Data collected in a single scan is stored in memory 41, the same-count identification function 442 performs a pairing process on the Single Data for that scan.

[0049] The image reconstruction function 443 generates a PET image by reconstructing the paired data generated by the coincidence count identification function 442. For example, the image reconstruction function 443 performs reconstruction using the ML-EM (Maximum Likelihood-Expectation Maximization) method or the OS-EM (Ordered Subset-Expectation Maximization) method, which is an accelerated version of the ML-EM method. Note that the image reconstruction function 443 may be implemented on a different processor (such as a GPU) than the coincidence count identification function 442.

[0050] Returning to Figure 1, the determination function 444 determines whether to temporarily store the collected Single Data in memory 121 based on the count rate of annihilation gamma rays or drug information regarding the drug administered to subject P. In other words, the determination of whether to temporarily store the collected Single Data in memory 121 is a determination of whether to transfer the collected Single Data to the console device 40 in groups or to transfer it each time it is collected without grouping.

[0051] For example, the determination function 444 may calculate a count rate indicating the number of annihilation gamma rays detected per unit time during the scan, and determine that temporary storage of Single Data is necessary if the calculated count rate is above a threshold.

[0052] Furthermore, the count rate of annihilation gamma rays can be estimated based on drug information regarding the drug administered to subject P. Therefore, the judgment function 444 may determine that temporary storage of Single Data is necessary if it estimates that the count rate of annihilation gamma rays is above a threshold based on the type of drug administered to subject P. The type of drug administered to subject P is included, for example, in the examination order transmitted from the Radiology Information System (RIS) to the PET device 1 via the network. The type of drug administered to subject P may also be entered by the user via the input interface 43.

[0053] Furthermore, the determination function 444 may determine whether to use a predetermined data size or a predetermined time length as the division unit for Single Data, based on the count rate of annihilation gamma rays or drug information regarding the drug administered to subject P.

[0054] The display control function 445 controls the display 42 to display various screens. For example, the display control function 445 displays a GUI on the display 42 that can accept user input for starting a scan and other various operations. The display control function 445 may also display the PET image generated by the image reconstruction function 443 on the display 42.

[0055] Here, using Figure 3, we will explain in more detail the pairing process for Single Data that has been transferred in multiple groups, and the deletion of Single Data.

[0056] Figure 3 shows an example of a unit for pairing data (Single Data) according to the first embodiment. In the example shown in Figure 3, the Single Data collected in one scan is divided into three groups, but the number of groups is just an example and is not limited to this.

[0057] In Figure 3, the horizontal axis represents the length of the data collection time, and the vertical axis represents the number of pairing operations. The same-count identification function 442 deletes the Singles Data of a group from memory 41 each time a pairing operation is performed on that group. However, Singles Data included in the time length corresponding to the timing window at the end of each group are excluded from deletion because they may be valid for the pairing operation of the next group. The time lengths between t2 and t3, and between t4 and t5, shown in Figure 3, are the same as the specified timing window in the pairing operation. Note that the time length of the timing window is generally a very short time, in the order of nanoseconds or picoseconds.

[0058] For example, suppose that the Singles Data 90a of the first group transferred from the mounting device 10 is count information with collection times from t1 to t3. Of the Singles Data 90a of the first group, the Singles Data within the range of the timing window width from the end of the collection time, i.e., the collection time from t2 to t3, is the non-deletion range 901a of the first group.

[0059] The same-count identification function 442 performs a pairing process to identify pairs of Single Data from the first group of Single Data 90a transferred from the mounting device 10 that correspond to two annihilation gamma rays emitted in opposing directions. After performing the pairing process for the first group of Single Data 90a, the same-count identification function 442 deletes from memory 41 all Single Data from the first group of Single Data 90a except for those collected at times t2 to t3.

[0060] The reason why Singles Data with collection times t2~t3 is not deleted is that two annihilation gamma rays that should be paired may be transferred separately to Singles Data 90a in the first group and to Singles Data 90b in the second group. In such cases, if all of Singles Data 90a in the first group is deleted before the pairing process for Singles Data 90b in the second group is completed, annihilation gamma rays that should be paired with the annihilation gamma rays included in Singles Data 90b in the second group may be deleted. For this reason, the coincidence counting identification function 442 does not delete Singles Data 90a in the first group with collection times within the timing window width from the end until the pairing process for Singles Data 90b in the second group is completed.

[0061] The same clock counting identification function 442 then performs a pairing process on the Singles Data included in the non-deletion range 901a of the first group and the Singles Data 90b of the second group that are then transferred from the mounting device 10. After pairing the Singles Data included in the non-deletion range 901a of the first group and the Singles Data 90b of the second group, the same clock counting identification function 442 deletes all Singles Data 90b of the second group except for those collected between t4 and t5. At this time, the same clock counting identification function 442 also deletes the Singles Data included in the non-deletion range 901a of the first group.

[0062] The reason why the same-count identification function 442 retains Single Data from the second group of Single Data 90b with collection times between t4 and t5 (i.e., Single Data included in the non-deletion range 901b of the second group) is that it is used for pairing with Single Data 90c of the third group.

[0063] The clock counting identification function 442 then performs a pairing process on the Singles Data included in the non-deletion range 901b of the second group, and on the Singles Data 90c of the third group that is then transferred from the mounting device 10. In the example shown in Figure 3, since the Singles Data 90c of the third group is the last data transferred from the mounting device 10, the clock counting identification function 442 deletes all the Singles Data from memory 41 after performing the pairing process on the Singles Data included in the non-deletion range 901b of the second group and on the Singles Data 90c of the third group.

[0064] Next, we will explain the processing flow performed by the PET apparatus 1 configured as described above.

[0065] Figure 4 is a sequence diagram showing an example of the processing flow according to the first embodiment. The processing shown in this sequence diagram starts, for example, when the user inputs an operation to start a scan.

[0066] First, the rigging device 10 starts detecting annihilation gamma rays emitted from the subject P using the detector 12, and collecting count information of the detected annihilation gamma rays (S1). For example, the front-end circuit 123 of each detector 12 generates raw data of the count information based on the electrical signal output from the detector module 12a. The processing circuit 122 generates single data from the raw data generated by the front-end circuit 123.

[0067] Furthermore, the determination function 444 of the console device 40 determines, for example, whether or not to temporarily store the Single Data in the memory 121 based on drug information regarding the drug administered to the subject P, or the estimated Single Data count rate (S2).

[0068] Then, the determination function 444 of the console device 40 transmits the determination result regarding whether or not the Single Data needs to be temporarily stored to the processing circuit 122 of the mounting device 10 (S3).

[0069] The processing circuit 122 saves the collected Single Data to the memory 121 according to the determination result of the determination function 444 of the console device 40. Specifically, if it is determined that temporary storage of Single Data is necessary (alt"Temporary data storage: required"), the processing circuit 122 of the mounting device 10 temporarily stores the generated Single Data in the memory 121 (S4).

[0070] Then, when the Single Data stored in the memory 121 reaches a specified data size, or when Single Data for a specified time length is stored in the memory 121, the processing circuit 122 of the mounting device 10 transfers the Single Data stored in the memory 121 as the Single Data 90a of the first group to the console device 40 via the DAS 11 (S5). The simultaneous counting identification function 442 of the processing circuit 44 of the console device 40 temporarily stores the Single Data 90a of the first group transferred from the mounting device 10 in the memory 41.

[0071] Furthermore, the processing circuit 122 of the mounting device 10 deletes the Single Data 90a of the first group that has been transferred to the console device 40 from the memory 121 (S6).

[0072] Then, the synchronization counting identification function 442 of the processing circuit 44 of the console device 40 sorts the temporarily stored Single Data 90a of the first group by detection time and generates Paired Data by performing a pairing process (S7). The synchronization counting identification function 442 stores the generated Paired Data in memory 41.

[0073] Then, the synchronization identification function 442 of the processing circuit 44 of the console device 40 deletes the Single Data 90a of the first group other than the specified non-deletion range 901a from the memory 41 (S8).

[0074] Furthermore, even after transferring the Single Data 90a of the first group in S5, the mounting device 10 continues to temporarily store newly collected counting information in the memory 121 (S9).

[0075] The processing circuit 122 of the mounting device 10 transfers the Single Data stored in memory 121 to the console device 40 via DAS 11 as the second group of Single Data 90b when the Single Data stored in memory 121 reaches a specified data size again, or when Single Data for a specified time length is stored in memory 121 again (S10). The simultaneous counting identification function 442 of the processing circuit 44 of the console device 40 temporarily stores the second group of Single Data 90b transferred from the mounting device 10 in memory 41.

[0076] Furthermore, the processing circuit 122 of the mounting device 10 deletes the Single Data 90b of the second group that has been transferred to the console device 40 from the memory 121 (S11).

[0077] Then, the synchronization count identification function 442 of the processing circuit 44 of the console device 40 sorts the Single Data 90a of the first group that falls within a specified non-deletion range 901a, and the temporarily stored Single Data 90b of the second group, by detection time, and performs a pairing process to generate Paired Data (S12). The synchronization count identification function 442 stores the generated Paired Data in memory 41.

[0078] Then, the synchronization identification function 442 of the processing circuit 44 of the console device 40 deletes the Single Data 90b of the second group other than the specified non-deletion range 901b from memory 41 (S13). At this time, the synchronization identification function 442 also deletes the Single Data of the specified non-deletion range 901a that was not deleted in S8 from memory 41.

[0079] Furthermore, even after transferring the Single Data 90b of the second group in S10, the mounting device 10 continues to temporarily store newly collected counting information in the memory 121 (S14).

[0080] At this point, the scanning of subject P is completed, and the collection of counting information is finished (S15). The processing circuit 122 of the stand device 10 transfers the Single Data stored in memory 121 as the Single Data 90c of the third group to the console device 40 via DAS 11 (S16). The simultaneous counting identification function 442 of the processing circuit 44 of the console device 40 temporarily stores the Single Data 90c of the third group transferred from the stand device 10 in memory 41.

[0081] Furthermore, the processing circuit 122 of the mounting device 10 deletes the third group of Single Data 90c that has been transferred to the console device 40 from the memory 121 (S17).

[0082] Then, the synchronization count identification function 442 of the processing circuit 44 of the console device 40 sorts the Single Data 90b of the second group that falls within a specified non-deletion range 901b, and the temporarily stored Single Data 90c of the third group, by detection time, and then performs a pairing process to generate Paired Data (S18). The synchronization count identification function 442 stores the generated Paired Data in memory 41.

[0083] At this point, since the pairing process for all Single Data is complete, the synchronization identification function 442 of the processing circuit 44 of the console device 40 deletes the Single Data 90c of the third group from memory 41 (S19). At the same time, the synchronization identification function 442 also deletes the Single Data in the specified non-deletion range 901b that was left in S13 from memory 41.

[0084] If the processing in S2 determines that temporary storage of Single Data is unnecessary (alt "Temporary data storage: No"), the processing circuit 122 of the stand device 10 does not consolidate the collected Single Data, but instead transfers the Single Data to the console device 40 via DAS 11 each time it is collected (S20). The transfer of Single Data continues until the scanning of the subject P is completed and the collection of counting information is finished. Then, the simultaneous counting identification function 442 of the processing circuit 44 of the console device 40 temporarily stores the Single Data transferred from the stand device 10 in memory 41.

[0085] The simultaneous counting identification function 442 of the processing circuit 44 of the console device 40 sorts the Single Data collected in one scan by detection time after all Single Data collected in one scan is stored in the memory 41, and then performs a pairing process (S21). The simultaneous counting identification function 442 stores the generated Paired Data in the memory 41.

[0086] The same clock number identification function 442 deletes the Single Data from memory 41 after the pairing process is completed (S22).

[0087] Then, the image reconstruction function 443 of the processing circuit 44 of the console device 40 generates a PET image by reconstructing the paired data generated by the coincidence count identification function 442 and stored in the memory 41 (S23).

[0088] The display control function 445 of the processing circuit 44 of the console device 40 causes, for example, the PET image generated by the image reconstruction function 443 to be displayed on the display 42 (S24). At this point, the processing in this sequence diagram ends.

[0089] In Figure 4, the Single Data collected in one scan is divided into three groups and transferred by the mounting device 10, but the number of groups of Single Data transferred is not limited to this.

[0090] As described above, the PET apparatus 1 of this embodiment comprises a stand device 10 and a console device 40. The stand device 10 collects Single Data of annihilation gamma rays emitted from the subject P and transfers the collected count information to the console device 40. The console device 40 performs a pairing process on the first group of Single Data 90a transferred from the stand device 10, and then deletes the Single Data 90a of the first group outside the specified non-deletion range 901a, leaving the Single Data within the specified non-deletion range 901a to be used for pairing the second group of Single Data 90b transferred from the stand device 10 next. Therefore, with the PET apparatus 1 of this embodiment, the burden on data transfer and storage can be reduced compared to the case where Single Data collected in a single scan is transferred all at once from the stand device 10 to the console device 40.

[0091] For example, in configurations with a large number of detector arrays, such as whole-body PET scanners, or in configurations with a large number of detector modules 12a included in a single detector 12 due to high resolution, a large amount of Single Data is collected in a single scan. In such a PET scanner 1, transferring all the Single Data collected in a single scan to the console device 40 at once would result in a high data transfer load. Furthermore, even if the Single Data is transferred from the rigging device 10 to the console device 40 little by little, if the console device 40 stores all the Single Data collected in a single scan before performing the pairing process, the amount of data stored on the console device 40 will increase.

[0092] In contrast, by deleting Single Data from the portion of the data after the pairing process is completed, as in the PET apparatus 1 of this embodiment, the amount of Single Data stored in memory 41 can be reduced. As a result, even if the amount of Single Data collected in a single scan increases, the storage capacity of the memory 121 on the rigging device 10 and the memory 41 of the console device 40 can be kept low.

[0093] Furthermore, the PET apparatus 1 of this embodiment does not simply delete Single Data belonging to a group after the pairing process has been completed, but rather leaves in the range that may contain Single Data that will be paired with Single Data belonging to the next group to be transferred from the rigging apparatus 10, thereby reducing Single Data pairing errors.

[0094] Furthermore, the PET apparatus 1 of this embodiment includes a bayonet 10 that stores the collected Single Data. The bayonet 10 of this embodiment transfers the Single Data stored in the bayonet 121 to the console device 40 at predetermined data size or acquisition time intervals. Therefore, according to the PET apparatus 1 of this embodiment, the Single Data can be divided into appropriate sizes and transferred to the console device 40.

[0095] Furthermore, in this embodiment, the PET apparatus 1's stand unit 10 transfers the Single Data stored in memory 121 to the console unit 40 as the first group of Single Data 90a when the Single Data stored in memory 121 reaches a predetermined data size or when Single Data for a predetermined time length is stored in memory 121. In addition, after the transfer of the first group of Single Data 90a, the PET apparatus 1's stand unit 10 deletes the first group of Single Data 90a from memory 121. Therefore, with this embodiment, even when a large amount of Single Data is collected, it is possible to avoid data overflow from the memory 121 of the stand unit 10.

[0096] Furthermore, in this embodiment, if the Single Data collected after the first group of Single Data 90a and stored in the memory 121 reaches a predetermined data size again, or if Single Data for a predetermined time length is stored in the memory 121 again, the gantry unit 10 of the PET apparatus 1 transfers the Single Data stored in the memory 121 to the console unit 40 as Single Data 90b of the second group, and after the transfer, deletes the Single Data 90b of the second group from the memory 121. In this way, according to the PET apparatus 1 of this embodiment, the gantry unit 10 transfers the collected Single Data sequentially to the console unit 40 in predetermined data size or predetermined time length increments, so that the console unit 40 can perform pairing processing in order from the Single Data of the group that was transferred first. Also, since the transferred Single Data is deleted from the memory 121 of the gantry unit 10, even if a large amount of Single Data is collected, the amount of data stored in the memory 121 of the gantry unit 10 can be reduced.

[0097] Furthermore, the console device 40 of the PET device 1 in this embodiment deletes from memory 41 any Single Data from the first group that is outside the specified non-deletion range 901a after the pairing process for the Single Data 90a of the first group. The console device 40 of the PET device 1 in this embodiment also performs pairing on the Single Data from the first group that is included in the specified non-deletion range 901a and on the Single Data 90b of the second group. Therefore, according to the PET device 1 in this embodiment, the memory 41 can be made free by deleting the Single Data after the pairing process is completed, and the pair can also be identified even when two Single Data to be paired are transferred across two groups.

[0098] Furthermore, the console device 40 of the PET apparatus 1 in this embodiment generates Paired Data by treating a combination of two Single Data 90a from the first group whose acquisition times are within a certain timing window width as information obtained by simultaneously counting two annihilation gamma rays. In addition, the predetermined non-deletion range 901a used when deleting Single Data from memory 41 is the range from the end of the acquisition time of the Single Data 90a in the first group to the timing window width. Therefore, according to the PET apparatus 1 in this embodiment, even if two Single Data included within a predetermined timing window to identify two events detected almost simultaneously are transferred across two groups, the pair can be identified.

[0099] Furthermore, the console device 40 of the PET apparatus 1 in this embodiment determines whether or not to save the collected Single Data to the memory 121 of the gantry stand device 10 based on the count rate of annihilation gamma rays or drug information regarding drugs administered to the subject P. The gantry stand device 10 of the PET apparatus 1 in this embodiment saves the collected Single Data to the memory 121 according to the determination result by the console device 40. For example, if the amount of Single Data collected in one scan is large, it is effective to reduce the load on data transfer and storage by dividing the Single Data into predetermined units and transferring them. However, if the amount of Single Data collected in one scan is small, there is no problem in transferring it from the gantry stand device 10 to the console device 40 as soon as it is collected without such processing. Therefore, according to the PET apparatus 1 of this embodiment, an appropriate transfer method can be adopted depending on the amount of Single Data collected in one scan.

[0100] (Second embodiment) In the first embodiment described above, the console device 40 of the PET apparatus 1 identified the specified non-deletion ranges 901a and 901b from the Single Data transferred in groups from the rigging device 10, and performed group-by-group pairing processing while deleting other Single Data while retaining the specified non-deletion ranges 901a and 901b. In this second embodiment, the rigging device 10 identifies the Single Data corresponding to the specified non-deletion ranges 901a and 901b, and transfers the transferred Single Data corresponding to the specified non-deletion ranges 901a and 901b together with the Single Data of the next group, thus creating a duplicate transfer.

[0101] The PET apparatus 1 of this embodiment includes a frame device 10, a bed device 30, and a console device 40, similar to the first embodiment described in Figure 1.

[0102] Furthermore, the detector 12 of the mounting device 10 in this embodiment includes a memory 121, a processing circuit 122, and a front-end circuit 123, similar to the first embodiment described in Figure 2. The flow of raw data, single data, and paired data is also the same as shown in Figure 2.

[0103] In the first embodiment, the processing circuit 122 of the mounting device 10 transferred Single Data to the console device 40 and then deleted the transferred Single Data from the memory 121. In contrast, in this embodiment, the processing circuit 122 of the mounting device 10 does not delete from the memory 121 the Single Data within a specified non-deletion range that is used for pairing the Single Data of the next group to be transferred. The processing circuit 122 of the mounting device 10 transfers the Single Data within a specified non-deletion range from the previously transferred group of Single Data to the console device 40 along with the Single Data of the next group to be transferred.

[0104] More specifically, in this embodiment, the processing circuit 122 of the mounting device 10 transfers the Single Data stored in the memory 121 to the console device 40 as Single Data 90a of the first group when the Single Data stored in the memory 121 reaches a predetermined data size or when Single Data for a predetermined time length is stored in the memory 121.

[0105] Then, after the transfer of the Single Data 90a of the first group, the processing circuit 122 of the mounting device 10 of this embodiment deletes from the memory 121 any Single Data 90a of the first group that is outside the specified non-deletion range 901a.

[0106] The specified non-deletion range 901a is, as in the first embodiment, for example, the range of the Singles Data 90a of the first group from the end of the collection time to the timing window width.

[0107] Then, in this embodiment, the processing circuit 122 of the mounting device 10 transfers the Single Data 90b of the second group stored in memory 121 and the Single Data within the specified non-deletion range 901a that remained in memory 121 without being deleted to the console device 40 when the Single Data collected after the first group of Single Data 90a and stored in memory 121 again reaches a specified data size, or when Single Data for a specified time length is stored in memory 121 again.

[0108] Furthermore, after transferring the Single Data 90b of the second group, the processing circuit 122 deletes the specified non-deletion range 901a of the Single Data 90a of the first group from memory 121. Also, after transferring the Single Data 90b of the second group, the processing circuit 122 deletes the Single Data from the second group that is outside the specified non-deletion range 901b from memory 121.

[0109] Then, in this embodiment, the processing circuit 122 of the mounting device 10 transfers the Single Data 90c of the third group stored in memory 121 and the Single Data within the specified non-deletion range 901b that remained in memory 121 without being deleted to the console device 40 when the Single Data collected after the second group of Single Data 90b and stored in memory 121 again reaches a specified data size, or when Single Data for a specified time length is stored in memory 121 again.

[0110] In this embodiment, the simultaneous count identification function 442 of the processing circuit 44 of the console device 40 may delete all Single Data of the target group after the pairing process for each group, without specifying the predetermined non-deletion ranges 901a and 901b.

[0111] Thus, in this embodiment, the rigging device 10 of the PET apparatus 1 transfers back to the console device 40, along with the next group, the range of Single Data already transferred to the console device 40 that is used for pairing with the next group of Single Data to be transferred. Therefore, in addition to the same effects as in the first embodiment, the rigging device 10 of the PET apparatus 1 of this embodiment does not require the console device 40 to identify the specified non-deletion ranges 901a and 901b and to perform deletion / non-deletion control processing.

[0112] (Variation 1) In the first and second embodiments described above, the memory 121, processing circuit 122, and front-end circuit 123 are provided for each detector 12, but a single memory 121 and processing circuit 122 may be provided for the entire mounting device 10. In this case, the DAS 11 may also include the memory 121 and processing circuit 122.

[0113] Alternatively, the mounting device 10 may include both a processing circuit 122 provided for each detector 12 and a single processing circuit (such as an FPGA) provided for the entire mounting device 10. In this case, the functions described as the functions of the processing circuit 122 in each of the embodiments described above may be divided and handled by the processing circuit 122 provided for each detector 12 and the single processing circuit provided for the entire mounting device 10.

[0114] (Modification 2) In the first embodiment described above, all or part of the determination function 444 of the processing circuit 44 of the console device 40 may be handled by the processing circuit 122 of the mounting device 10. Also, in Figure 4, the determination function 444 of the console device 40 determines whether or not to temporarily store the Single Data in the memory 121 before the initial transfer, but the timing of the determination is not limited to this and may be during the collection of Single Data.

[0115] For example, if there is a sudden increase in the count rate during scanning, control may be provided so that the mounting device 10 transfers data to the console device 40 before the memory 121 overflows.

[0116] More specifically, the processing circuit 122 of the mounting device 10 may transfer the Singles Data stored in memory 121 to the console device 40 and delete it from memory 121 if the Singles Data count rate exceeds a threshold during Singles Data acquisition.

[0117] By changing the transfer unit size of Singles Data to an appropriate size during scanning, in addition to the effects of the first and second embodiments described above, it becomes possible to handle high load conditions caused by the collection of large amounts of Singles Data.

[0118] (Variation 3) Furthermore, depending on the configuration of the PET apparatus 1, it may be expected that the amount of Single Data collected will always be large. For this reason, the PET apparatus 1 may be configured to always temporarily store the Single Data in the memory 121 of the rigging device 10. In this case, since there is no need to determine whether or not temporary storage is necessary, the PET apparatus 1 does not need to have a determination function 444.

[0119] (Modification 4) Furthermore, in the first and second embodiments described above, the console device 40 instructed the mounting device 10 on the data transfer method before the start of Singles Data transfer, and during the transfer, Singles Data was transferred from the mounting device 10 to the console device 40 using a push method. However, the data transfer method is not limited to this procedure.

[0120] For example, a pull-type transfer method may be employed in which the console device 40 requests the transfer of Singles Data to the mounting device 10.

[0121] Specifically, the concurrency identification function 442 of the console device 40 may request the mounting device 10 to transfer the next group of Singles Data when the pairing process of the transferred Singles Data is completed. In this pull-type transfer method, data can be transferred from the mounting device 10 at a timing corresponding to the processing speed of the console device 40.

[0122] (Variation 5) In the first and second embodiments described above, the specified non-deletion ranges 901a and 901b to be retained for the pairing process of the next group were defined as the range from the end of the Single Data collection time for each group to the timing window width; however, the specified non-deletion ranges 901a and 901b are not limited to these.

[0123] For example, the specified non-deletion ranges 901a and 901b may have a time length longer than the timing window in order to absorb the calculation of accidental coincidence counts using the delayed coincidence counting method and the time difference in data transmission between multiple detectors 12.

[0124] The various types of data discussed in this specification are typically digital data.

[0125] According to at least one embodiment described above, the burden related to data transfer and storage in nuclear medicine diagnostic devices can be reduced.

[0126] While several embodiments have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be implemented in a variety of other forms, and various omissions, substitutions, modifications, and combinations of embodiments are possible without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0127] 1 PET device 10. Mounting device 11 DAS 12 detectors 12a Detector Module 30 Bed equipment 31 base 32 Bed drive mechanism 33 Top plate 34. Tabletop support frame 40 Console device 41,121 memory 42 displays 43 Input Interfaces 44,122 Processing Circuits 123 Front-end circuit 441 System control function 442 Simultaneous counting identification function 443 Image reconstruction function 444 Judgment function 445 Display control function 901a, 901b Non-deleted range d length P Subject

Claims

1. Equipped with a mounting frame and a console, The aforementioned mounting device is A collection unit that collects count information on annihilation gamma rays emitted from the subject, The system includes a transfer unit that transfers the collected counting information to the console device, The console device is A first storage unit that stores the counting information transferred from the aforementioned mounting device, The system includes a simultaneous counting identification unit that, after performing a pairing process to identify a pair of counting information corresponding to two annihilation gamma rays emitted in opposing directions from a first group of counting information transferred from the mounting device, deletes the counting information outside the specified non-deletion range from the first group of counting information, while retaining the counting information within the specified non-deletion range from the first group of counting information to be used in the pairing process for the second group of counting information to be transferred from the mounting device. Nuclear medicine diagnostic equipment.

2. The aforementioned mounting device further comprises a second storage unit for storing the collected counting information, The transfer unit transfers the counting information stored in the second storage unit to the console device at predetermined data size or collection time intervals. The nuclear medicine diagnostic device according to claim 1.

3. When the counting information stored in the second storage unit reaches the specified data size, or when the counting information for a specified time length is stored in the second storage unit, the transfer unit transfers the counting information stored in the second storage unit as the first group to the console device, and after the transfer, deletes the counting information of the first group from the second storage unit. The nuclear medicine diagnostic device according to claim 2.

4. The transfer unit, when the counting information collected after the first group of counting information and stored in the second storage unit reaches the specified data size again, or when the counting information for the specified time length is stored in the second storage unit again, transfers the counting information stored in the second storage unit as a second group to the console device, and after the transfer, deletes the counting information of the second group from the second storage unit. The nuclear medicine diagnostic device according to claim 3.

5. The aforementioned clock counting identification unit is After the pairing process for the counting information of the first group, the counting information of the first group that is outside the specified non-deletion range is deleted from the first storage unit. The pairing process is performed on the counting information of the first group that is included in the specified non-deletion range and on the counting information of the second group. The nuclear medicine diagnostic device according to claim 4.

6. The console device further comprises a determination unit that determines whether or not to store the collected counting information in the second storage unit based on the count rate of the annihilation gamma rays or drug information relating to the drug administered to the subject. The transfer unit of the mounting device stores the collected counting information in the second storage unit according to the determination result by the determination unit. The nuclear medicine diagnostic device according to claim 2.

7. The aforementioned mounting device further comprises a second storage unit for storing the collected counting information, The transfer unit is, When the counting information stored in the second storage unit reaches the specified data size, or when the counting information for a specified time length is stored in the second storage unit, the counting information stored in the second storage unit is transferred to the console device as the first group. After the transfer of the counting information of the first group, the counting information of the first group that is outside the specified non-deletion range is deleted from the second storage unit. When the counting information collected after the counting information of the first group and stored in the second storage unit reaches the specified data size again, or when the counting information for the specified time length is stored in the second storage unit again, the counting information of the second group stored in the second storage unit and the counting information of the first group within the specified non-deletion range are transferred to the console device. The nuclear medicine diagnostic device according to claim 1.

8. The transfer unit, when the count rate of the count information exceeds a threshold during the collection of the count information, transfers the count information stored in the second storage unit to the console device and deletes it from the second storage unit. The nuclear medicine diagnostic device according to claim 2.

9. The aforementioned same-count identification unit generates same-count information by considering a combination of two of the count information from the first group whose collection times are within a certain timing window width as information obtained by simultaneously counting two of the annihilation gamma rays. The non-deletion range specified above is the range of the first group of count information from the end of the collection time to the timing window width. A nuclear medicine diagnostic device according to any one of claims 1 to 8.

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