JP6091852B2 - Nuclear medicine diagnostic apparatus and image processing program - Google Patents

Description

  Embodiments described herein relate generally to a nuclear medicine diagnostic apparatus and an image processing program.

  A nuclear medicine diagnostic apparatus uses a property that a medicine (blood flow marker, tracer) containing a radioisotope (hereinafter referred to as RI) is selectively taken into a specific tissue or organ in the living body. Gamma rays emitted from the distributed RI are detected by a gamma ray detector disposed outside the living body. The detection result of gamma rays is used for generation of nuclear medicine images by imaging the dose distribution of gamma rays, diagnosis of functions of internal organs and the like.

  A captured image of a portion close to the lung, such as the chest and abdomen, is affected by respiratory motion. For this reason, when photographing the chest or abdomen, it is preferable to reduce the influence of respiratory motion.

Japanese Laid-Open Patent Publication No. 2004-45318

  However, some parts of the captured image that are affected by respiratory motion are also affected by the heartbeat. For this reason, when this type of part is imaged, it is preferable to reduce the influence of the pulsation on the image in addition to the respiratory movement.

In order to solve the above-described problem, a nuclear medicine diagnostic apparatus according to an embodiment of the present invention is provided with a plurality of detectors that detect gamma rays emitted from a radioisotope administered to a subject, and attached to the subject. A data collection unit for collecting the output data of the respiratory sensor and the electrocardiogram sensor and the output data of a plurality of detectors, and the in-phase period of respiratory motion based on the data collected by the data collection unit In addition, an image generation unit that generates images based on the output data of the plurality of detectors in the first period, in which the heart motion is smaller than the threshold , and the pair of annihilation gamma ray pairs based on the output data of the plurality of detectors And a heart region specifying unit that specifies data derived from the heart region from the detection time difference . The image generation unit includes a predetermined number of periods among a plurality of second periods in which the output data of the plurality of detectors in the first period and the in-phase period of the respiratory motion are periods in which the heart motion is greater than the threshold value By deleting data derived from the heart region from the output data of the plurality of detectors in, data obtained by thinning out the data derived from the heart region from the output data of the plurality of detectors in the plurality of second periods, An image is generated based on this.

1 is a block diagram showing an example of a nuclear medicine diagnostic apparatus according to a first embodiment of the present invention. The schematic block diagram which shows the structural example of the function implementation part by CPU of the control part which concerns on 1st Embodiment. Explanatory drawing which shows an example of the list mode data handled by the simultaneous counting part. (A) is explanatory drawing which shows an example of the conventional image generation method which produces | generates the image of the whole lung from the coincidence count information which belongs to the same phase period of respiratory motion, (b) is a lung from the coincidence count information which belongs to the 1st period. Explanatory drawing which shows an example of the image generation method which concerns on this embodiment which produces | generates the whole image. The flowchart which shows the procedure at the time of reducing the influence with respect to the captured image by respiration and pulsation by CPU of the control part shown in FIG. The schematic block diagram which shows the structural example of the function implementation part by CPU of the control part which concerns on 2nd Embodiment. The flowchart which shows the procedure at the time of reducing the influence with respect to the captured image by respiratory motion and a pulsation by CPU of the control part shown in FIG. The schematic block diagram which shows the structural example of the function implementation part by CPU of the control part which concerns on 3rd Embodiment. The flowchart which shows the procedure at the time of reducing the influence with respect to the captured image by respiration and pulsation by CPU of the control part shown in FIG. The schematic block diagram which shows the structural example of the function implementation part by CPU of the control part which concerns on 3rd Embodiment. The flowchart which shows the procedure at the time of reducing the influence with respect to the captured image by respiration and pulsation by CPU of the control part shown in FIG.

Embodiments of a nuclear medicine diagnosis apparatus and an image processing program according to the present invention will be described with reference to the accompanying drawings.
(First embodiment)

  FIG. 1 is a block diagram showing an example of a nuclear medicine diagnostic apparatus according to the first embodiment of the present invention. In the following description, an example in which a PET (Positron Emission Tomography) apparatus is used as the nuclear medicine diagnostic apparatus according to the present invention will be described.

  The nuclear medicine diagnostic apparatus 10 includes a scanner device 11 and an image processing device 12. The scanner device 11 includes a top plate 21, a top plate driving device 22, a plurality of detectors 23, a detector cover 24, and a data collection unit 25.

  The top plate 21 is configured so that a patient (subject) O can be placed thereon. The top plate driving device 22 is controlled by the image processing device 12 to move the top plate 21 up and down. Further, the top plate driving device 22 is controlled by the image processing device 12 to transfer the top plate 21 along the long axis direction of the top plate 21 to the opening of the central portion of the detector cover 24.

  The detector 23 is a detector that detects gamma rays emitted from a radioisotope contained in a medicine such as FDG (fluorodeoxyglucose) and administered to the patient O. As the detector 23, a scintillator type detector or a semiconductor type detector may be used.

  When a scintillator type detector is used, the detector 23 detects a collimator for defining the incident angle of the gamma ray, a scintillator that emits an instantaneous flash when the collimated gamma ray is incident, and light emitted from the scintillator. A plurality of photomultiplier tubes arranged in a two-dimensional manner, an electronic circuit for a scintillator, and the like.

  The scintillator is made of, for example, thallium activated sodium iodide NaI (Tl). The scintillator electronic circuit has information on the incident position of gamma rays in a detection plane constituted by a plurality of photomultiplier tubes based on the output of the plurality of photomultiplier tubes every time an event in which gamma rays are incident occurs. (Position information) and intensity information are generated and output to the data collection unit 25.

  On the other hand, when a semiconductor detector is used, the detector 23 includes a collimator, a plurality of gamma ray detecting semiconductor elements (hereinafter referred to as semiconductor elements) arranged in two dimensions for detecting collimated gamma rays, and a semiconductor detector. It has an electronic circuit.

  The semiconductor element is made of, for example, CdTe or CdZnTe (CZT). The semiconductor electronic circuit generates position information and intensity information based on the output of the semiconductor element and outputs them to the data collecting unit 25 every time an event in which gamma rays are incident occurs.

  The plurality of detectors 23 are arranged in the detector cover 24 in a hexagonal shape or a circular shape so as to surround the periphery of the patient O, for example. The arrangement of the plurality of detectors 23 is not limited to the ring arrangement type. For example, the plurality of detectors 23 arranged on a flat plate can be rotated around the patient O while the two detectors 23 are opposed to each other with the patient O interposed therebetween. You may arrange | position to the 2 detector opposing type | mold hold | maintained. The plurality of detectors 23 may be arranged in a multilayer ring so that images between adjacent layers can be acquired.

  A respiratory sensor 26 and an electrocardiographic sensor 27 are attached to the patient O. The respiratory sensor signal output from the respiratory sensor 26 and the electrocardiographic sensor signal (ECG (Electro CardioGram) signal) output from the electrocardiographic sensor 27 are supplied to the data collecting unit 25.

  The data collection unit 25 collects the outputs of the plurality of detectors 23 in a list mode. In the list mode, gamma ray detection position information, intensity (energy) information, information indicating the relative position between the detector 23 and the patient O (position and angle of the detector 23, etc.), and gamma ray detection time are incident events of gamma rays. Collected every time. In addition, the data collection unit 25 associates the information of the respiratory sensor signal and ECG signal of the patient O received from the respiratory sensor 26 and the electrocardiographic sensor 27 with the list mode data, and stores it in a RAM or the like included in the data collection unit 25. Store on media.

  As illustrated in FIG. 1, the image processing apparatus 12 includes a control unit 31, a display unit 32, an input unit 33, and a storage unit 34.

  The control unit 31 includes a storage medium such as a CPU, a RAM, and a ROM, and controls the processing operation of the image processing apparatus 12 according to a program stored in the storage medium.

  The CPU of the control unit 31 loads an image processing program stored in a storage medium such as a ROM and data necessary for the execution of the program into the RAM, and performs captured motion images and respiratory images according to the program. Perform processing to reduce the impact.

  The RAM of the control unit 31 provides a work area for temporarily storing programs and data executed by the CPU. The storage medium such as the ROM of the control unit 31 stores a startup program for the image processing device 12, an image processing program, and various data necessary for executing these programs.

  A storage medium such as a ROM has a configuration including a recording medium readable by a CPU, such as a magnetic or optical recording medium or a semiconductor memory, and a part of programs and data in the storage medium. Or you may comprise so that all may be downloaded via an electronic network.

  The display unit 32 is configured by a general display output device such as a liquid crystal display or an OLED (Organic Light Emitting Diode) display, and displays various types of information such as a nuclear medicine diagnosis image according to the control of the control unit 31.

  The input unit 33 is configured by a general input device such as a keyboard, a touch panel, or a numeric keypad, and outputs an operation input signal corresponding to a user operation to the control unit 31.

  The storage unit 34 has a configuration that includes a CPU-readable recording medium such as a magnetic or optical recording medium or a semiconductor memory, and some or all of the programs and data in the storage medium are stored in an electronic network. You may comprise so that it may be downloaded via. The storage unit 34 is controlled by the control unit 31 and stores synchronization count information, nuclear medicine images, and the like.

  FIG. 2 is a schematic block diagram illustrating a configuration example of the function realization unit by the CPU of the control unit 31 according to the first embodiment. In addition, this function realization part may be comprised by hardware logics, such as a circuit, without using CPU.

  As illustrated in FIG. 2, the CPU of the control unit 31 functions as at least a scan control unit 41, a coincidence counting unit 42, a cardiopulmonary synchronization data extraction unit 43, and an image generation unit 44 according to an image processing program. Each of the units 41 to 44 uses a required work area of the RAM as a temporary storage location for data.

  The scan control unit 41 receives a scan plan execution instruction from the user via the input unit 33, and controls the scanner device 11 based on the scan plan to execute a scan. As a result, information on the gamma rays emitted from the patient O, information on the respiration sensor signal of the patient O, and information on the ECG signal are given from the scanner device 11 to the coincidence unit 42 via the data collection unit 25.

  FIG. 3 is an explanatory diagram showing an example of list mode data handled by the coincidence counting unit 42. FIG. 3 shows only the data on the pair annihilation gamma rays counted simultaneously. In FIG. 3, Detectors # 1 and # 2 indicate numbers indicating the positions of the detectors 23 on which the coincidence pair annihilation gamma rays are incident, and T indicates a time from the start of data collection until gamma rays are incident (pair annihilation gamma rays. The average of the two detection times), Δt is the difference in the detection time of the annihilation gamma ray (hereinafter referred to as the incident time difference), and Energy # 1 and # 2 are the incident energy of the gamma rays detected by Detector # 1 and # 2, respectively. Are shown respectively.

  The coincidence counting unit 42 receives from the data collecting unit 25 list mode data associated with information on respiratory sensor signals (respiration motion data) and information on ECG signals (electrocardiographic waveform data).

  The coincidence counting unit 42 has a gamma ray incident time difference (difference in detection time of annihilation gamma rays) within a predetermined time window width (for example, within 1 ns) in the list mode data, and each incidence of two pair annihilation gamma rays. A combination in which both energies are within a predetermined energy window width is extracted. The coincidence unit 42 provides the extracted list mode data (hereinafter referred to as coincidence information) to the cardiopulmonary synchronization data extraction unit 43 and the image generation unit 44.

  In the present embodiment, an example in which the control unit 31 of the image processing apparatus 12 generates the coincidence counting information has been described. However, the coincidence counting information is generated by, for example, the data collection unit 25 of the scanner apparatus 11 and the image processing apparatus 12. May be given.

  The cardiopulmonary synchronization data extraction unit 43 extracts coincidence counting information belonging to the same phase period of respiratory motion from the coincidence counting information received from the coincidence counting unit 42. The cardiopulmonary synchronization data extraction unit 43 also includes a period in which the heart motion is smaller than a predetermined threshold (hereinafter referred to as a first period) and a period (hereinafter referred to as a first period) greater than the threshold for the data belonging to the same phase period of the extracted respiratory motion. (Referred to as “second period”). Further, the cardiopulmonary synchronization data extraction unit 43 excludes the data belonging to the second period from the extracted in-phase data of the respiratory motion, that is, the extracted in-phase period and the period during which the heart motion is smaller than the threshold (the first The coincidence counting information belonging to (period 1) is extracted and given to the image generation unit 44.

  FIG. 4A is an explanatory diagram showing an example of a conventional image generation method for generating an image of the entire lung 51 from coincidence counting information belonging to the same phase period of respiratory motion, and FIG. 4B belongs to the first period. It is explanatory drawing which shows an example of the image generation method which concerns on this embodiment which produces | generates the image of the whole lung 51 from coincidence information.

  By extracting the coincidence counting information belonging to the same phase period of the respiratory motion, it is possible to reduce the influence of the respiratory motion on the image. However, in the same phase period of respiratory motion, there are a first period in which the movement (beat) of the heart 52 is small and a period (second period) in which the movement of the heart is large. For this reason, when an image of the entire lung 51 is generated from the coincidence counting information belonging to the same phase period of respiratory motion, as shown in FIG. 4A, the image of the heart 52 is affected by the movement of the heart 52. In addition to blurring, an image of an organ in the lung field such as the bronchi 53 affected by the motion of the heart 52 is also blurred.

  Therefore, the nuclear medicine diagnosis apparatus 10 according to the present embodiment reduces the influence on the image due to respiratory motion and pulsation, so that the entire lung 51 is obtained from the coincidence count information belonging to the first period as shown in FIG. Generate an image of

  The image generation unit 44 performs synchronization reconstruction based on the coincidence count information belonging to the first period extracted by the cardiopulmonary synchronization data extraction unit 43, generates an image, and causes the display unit 32 to display the image.

  Next, an example of the operation of the nuclear medicine diagnostic apparatus 10 according to the present embodiment will be described.

  FIG. 5 is a flowchart showing a procedure when the influence of the respiratory motion and pulsation on the captured image is reduced by the CPU of the control unit 31 shown in FIG. In FIG. 5, reference numerals with numbers added to S indicate steps in the flowchart.

  First, in step S <b> 1, the patient O who has received a drug such as FDG is placed on the top plate 21. A respiration sensor 26 and an electrocardiographic sensor 27 are attached to the patient O, and information on the respiration sensor signal and the ECG signal of the patient O is given to the data collection unit 25.

  Next, in step S2, the scan control unit 41 receives a scan plan execution instruction from the user via the input unit 33, and controls the scanner device 11 based on the scan plan to execute the scan.

  Next, in step S3, the data collection unit 25 generates list mode data in which respiratory motion data and electrocardiographic waveform data are associated. The coincidence counting unit 42 acquires list mode data in which the respiratory motion data and the electrocardiographic waveform data are associated with each other.

  Next, in step S <b> 4, the cardiopulmonary synchronization data extraction unit 43 extracts data belonging to the same phase period of respiratory motion from the coincidence counting information received from the coincidence counting unit 42.

  Next, in step S5, the cardiopulmonary synchronization data extraction unit 43 extracts a period (first period) in which the heart motion is smaller than a predetermined threshold and a period (a period greater than the threshold) ( The second period) is specified.

  Next, in step S <b> 6, the cardiopulmonary synchronization data extraction unit 43 excludes the data belonging to the second period from the extracted in-phase data of the respiratory motion and gives the data to the image generation unit 44.

  Next, in step S7, the image generation unit 44 performs synchronization reconstruction based on the data (simultaneous counting information) belonging to the first period received from the cardiopulmonary synchronization data extraction unit 43, generates an image, and displays the display unit 32. To display.

  By the above procedure, it is possible to reduce the influence on the captured image due to respiratory motion and pulsation.

  The nuclear medicine diagnosis apparatus 10 according to the present embodiment can generate an image based on coincidence count information in a period (first period) in which the heart motion is smaller than a threshold in the same phase period of respiratory motion. . For this reason, compared with the case where an image is generated using all the data belonging to the same phase period of the respiratory motion, an image with reduced influence due to the respiratory motion and the pulsation can be generated. For this reason, the resolution of the image of the lung field around the heart can be improved, and the user can perform quantitative diagnosis more accurately.

In addition, although this embodiment demonstrated the case where a PET apparatus was used as the nuclear medicine diagnostic apparatus 10, the technique which concerns on this embodiment is applicable to a SPECT apparatus. When applied to a SPECT apparatus, the structure of the detector 23 may be a structure used for a general SPECT apparatus. When the SPECT apparatus is used, the coincidence counting unit 42 is unnecessary, and list mode data associated with respiratory motion data and electrocardiographic waveform data may be acquired from the data collection unit 25 by the cardiopulmonary synchronization data extraction unit 43.
(Second Embodiment)

  Next, a second embodiment of the nuclear medicine diagnosis apparatus 10 and the image processing program according to the present invention will be described.

  The nuclear medicine diagnostic apparatus 10 according to the present embodiment uses data of a portion far from the heart 52 in the coincidence counting information in the second period for synchronous reconstruction.

  FIG. 6 is a schematic block diagram illustrating a configuration example of a function implementing unit by the CPU of the control unit 31A according to the second embodiment.

  The nuclear medicine diagnosis apparatus 10 shown in the second embodiment is different from the control part 31 of the nuclear medicine diagnosis apparatus 10 shown in the first embodiment in the configuration of the control part 31A. Since other configurations and operations are not substantially different from those of the nuclear medicine diagnostic apparatus 10 shown in FIG. 1, the same components are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 6, the CPU of the control unit 31A functions as at least a scan control unit 41, a coincidence counting unit 42, a cardiopulmonary synchronization data extracting unit 43A, a heart region specifying unit 61, and an image generating unit 44A according to an image processing program. . Each unit uses a required work area of the RAM as a temporary storage location for data.

  The cardiopulmonary synchronization data extraction unit 43A extracts coincidence counting information belonging to the same phase period of respiratory motion from the coincidence counting information received from the coincidence counting unit 42. Further, the cardiopulmonary synchronization data extraction unit 43 specifies whether the extracted data belonging to the same phase period of the respiratory motion belongs to the first period or the second period.

  The heart region specifying unit 61 specifies the data derived from the region of the heart 52 (heart region) in the coincidence count information by identifying the generation position of the pair annihilation gamma ray pair based on the incident time difference of the coincidence count information. Here, the outline of the heart region may be set to the outline of the heart 52 or may be set to a predetermined range from the outline of the heart 52 including the heart 52. In the latter case, the heart region includes the vicinity of the heart 52.

  The image generation unit 44A uses the coincidence count information belonging to the first period as it is for the synchronization reconstruction, while the coincidence count information belonging to the second period is thinned or weighted for data derived from the heart region. An image is generated by using a smaller or smaller image for synchronization reconstruction and displayed on the display unit 32.

Here, “thinning the data derived from the heart region for the coincidence counting information belonging to the second period” means the data every predetermined period (for example, one in 5 periods) among the plurality of second periods. is used for synchronization reconstruct all of the data, including the heart臓領region, from other data shall refer to delete data from the cardiac region.

  FIG. 7 is a flowchart illustrating a procedure when the influence of the respiratory motion and the pulsation on the captured image is reduced by the CPU of the control unit 31A illustrated in FIG. In FIG. 7, reference numerals with numbers added to S indicate steps in the flowchart. Steps equivalent to those in FIG. 5 are denoted by the same reference numerals, and redundant description is omitted.

  The cardiopulmonary synchronization data extraction unit 43A extracts data belonging to the same phase period of respiratory motion from the coincidence information (step S4), and the data belonging to the same phase period of respiratory motion is the first period second period It is specified to which data belongs to (step S5).

  Next, in step S21, the heart region specifying unit 61 specifies the generation position of the pair annihilation gamma ray pair based on the incident time difference of the coincidence information, thereby obtaining data derived from the region of the heart 52 in the coincidence information. Identify.

  Next, in step S22, the image generation unit 44A thins out the data derived from the heart region from the coincidence counting information belonging to the first period and the coincidence counting information belonging to the second period, or reduces the weight, Alternatively, an excluded image is used for synchronous reconstruction, and an image is generated and displayed on the display unit 32.

  Also by the above procedure, the influence on the captured image by respiratory motion and pulsation can be reduced.

  The nuclear medicine diagnosis apparatus 10 according to the second embodiment uses the coincidence counting information in the first period for the synchronous reconfiguration as in the first embodiment, and all the coincidence counting information in the second period. Rather than being excluded, data relating to the heart region is thinned out, weights are reduced, or excluded and used for synchronous reconstruction.

Of the lung field region, the part far from the heart 52 is not easily affected by the movement of the heart. Therefore, by using the data far from the heart 52 in the coincidence counting information in the second period for the synchronous reconstruction, the heart in the lung field region is compared with the nuclear medicine diagnostic apparatus 10 according to the first embodiment. The image of the part far from 52 can be made clearer.
(Third embodiment)

  Next, a nuclear medicine diagnostic apparatus and an image processing program according to a third embodiment of the present invention will be described.

  The nuclear medicine diagnosis apparatus 10 according to the present embodiment generates an image by applying position filters having different strengths to the heart region in the first period and the second period.

  FIG. 8 is a schematic block diagram illustrating a configuration example of a function realization unit by the CPU of the control unit 31B according to the third embodiment.

  In the nuclear medicine diagnostic apparatus 10 shown in the third embodiment, the configuration of the control unit 31B is different from the control unit 31 of the nuclear medicine diagnostic apparatus 10 shown in the first embodiment. Since other configurations and operations are not substantially different from those of the nuclear medicine diagnostic apparatus 10 shown in FIG. 1, the same components are denoted by the same reference numerals and description thereof is omitted. In addition, the functions of the cardiopulmonary synchronization data extraction unit 43A and the heart region specifying unit 61 are not substantially different from the configuration according to the second embodiment, and thus the description thereof is omitted.

  In general, when a nuclear medicine image is generated, a position filter such as a Gaussian filter is applied to position information obtained from coincidence count information. This is a measure that takes into account an error in time of flight (TOF). By applying a position filter to the position information obtained from the coincidence information to blur the position, the position information can be corrected to take account of the TOF measurement error.

  The image generation unit 44B according to the present embodiment varies the position blurring using this position filter, that is, the strength of the position filter, between a heart region in motion and another region (for example, a lung field region).

  Specifically, the image generation unit 44B performs position filtering on the position information obtained from the coincidence counting information belonging to the first period with a predetermined kernel width, and the position obtained from the coincidence counting information belonging to the second period. For the information, a predetermined kernel width is used for the lung field region, while a position filter is applied to the heart region with a kernel width different from the predetermined kernel width. When a Gaussian filter is used as the position filter, the kernel width (filter strength) can be changed by changing the variance value of the Gaussian function.

  FIG. 9 is a flowchart illustrating a procedure when the influence of the respiratory motion and the pulsation on the captured image is reduced by the CPU of the control unit 31B illustrated in FIG. In FIG. 9, the code | symbol which attached | subjected the number to S shows each step of a flowchart. Steps equivalent to those in FIGS. 5 and 7 are denoted by the same reference numerals, and redundant description is omitted.

  In step S31, the image generation unit 44B performs position filtering on the position information obtained from the coincidence counting information belonging to the first period with a predetermined kernel width, and the position information obtained from the coincidence counting information belonging to the second period. For the lung field region, a predetermined kernel width is used, while for the heart region, a position filter is applied with a kernel width different from the predetermined kernel width. Then, the image generation unit 44B generates an image using the data on which the position filter has been applied, and causes the display unit 32 to display the image.

  Also by the above procedure, the influence on the captured image by respiratory motion and pulsation can be reduced.

  The nuclear medicine diagnosis apparatus 10 according to the third embodiment uses the coincidence count information in the first period and the second period, similarly to the nuclear medicine diagnosis apparatus 10 according to the second embodiment. For this reason, compared with the nuclear medicine diagnostic apparatus 10 according to the first embodiment, an image of a portion far from the heart 52 in the lung field region can be made clearer. In addition, regarding the position information obtained from the coincidence counting information belonging to the second period, the predetermined kernel width is used for the lung field region, while the kernel region is positioned with a kernel width different from the predetermined kernel width. Apply a filter. For this reason, the image quality can be improved as compared with the case where an image is generated using all data belonging to the same phase period of respiratory motion.

  For example, when the kernel width of the heart region is sharpened more than a predetermined kernel width in the second period (a period in which the heart motion is large), an image of the heart region that tends to be blurred due to pulsation is sharpened. It is possible to obtain a uniform image in the heart region and the lung region.

On the other hand, when the kernel width of the heart region is broader than the predetermined kernel width in the second period (period in which the heart motion is large), the image of the heart region is blurred, but the image capturing the entire motion of the heart 52 (An image reflecting the existence probability including an error of heart motion) can be generated.
(Fourth embodiment)

  Next, a nuclear medicine diagnosis apparatus and an image processing program according to a fourth embodiment of the present invention will be described.

  A nuclear medicine diagnosis apparatus 10 according to the present embodiment is a combination of the nuclear medicine diagnosis apparatus 10 according to the second embodiment and the nuclear medicine diagnosis apparatus 10 according to the third embodiment.

  FIG. 10 is a schematic block diagram illustrating a configuration example of the function realization unit by the CPU of the control unit 31B according to the third embodiment.

  In the nuclear medicine diagnostic apparatus 10 shown in the third embodiment, the configuration of the control unit 31C is different from the control unit 31 of the nuclear medicine diagnostic apparatus 10 shown in the first embodiment. Since other configurations and operations are not substantially different from those of the nuclear medicine diagnostic apparatus 10 shown in FIG. 1, the same components are denoted by the same reference numerals and description thereof is omitted. Further, the functions of the cardiopulmonary synchronization data extracting unit 43A and the heart region specifying unit 61 are not substantially different from the configurations according to the second embodiment and the third embodiment, and thus description thereof is omitted.

  FIG. 11 is a flowchart illustrating a procedure when the influence of the respiratory motion and the pulsation on the captured image is reduced by the CPU of the control unit 31C illustrated in FIG. In FIG. 11, reference numerals with numbers added to S indicate the steps in the flowchart. Steps equivalent to those in FIGS. 5, 7, and 9 are denoted by the same reference numerals, and redundant description is omitted.

  The image generation unit 44C uses the coincidence counting information belonging to the first period as it is for the synchronization reconstruction, while the coincidence counting information belonging to the second period is thinned or weighted for data derived from the heart region. It is made smaller (step S41 in FIG. 11). The difference between the image generation unit 44A according to the second embodiment is that data derived from the heart region is not deleted.

  Similarly to the image generation unit 44B according to the third embodiment, the image generation unit 44C applies a position filter with a predetermined kernel width to the position information obtained from the coincidence counting information belonging to the first period, For the position information obtained from the coincidence count information belonging to this period, a predetermined kernel width is used for the lung field region, while a position filter is applied to the heart region with a kernel width different from the predetermined kernel width. Then, an image is generated and displayed on the display unit 32 (step S42 in FIG. 11).

  The nuclear medicine diagnosis apparatus 10 according to the fourth embodiment uses coincidence count information in the first period and the second period. For this reason, compared with the nuclear medicine diagnostic apparatus 10 according to the first embodiment, an image of a portion far from the heart 52 in the lung field region can be made clearer. In addition, the image quality of the heart region can be further improved by not only thinning out or reducing the weighting of the heart region data in the second period, but also making the strength of the position filter different from that of the lung field region.

  In addition, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  Further, in the embodiment of the present invention, each step of the flowchart shows an example of processing that is performed in time series in the order described. The process to be executed is also included.

DESCRIPTION OF SYMBOLS 10 Nuclear medicine diagnostic apparatus 23 Detector 25 Data collection part 26 Respiration sensor 27 Electrocardiograph sensor 31, 31A, 31B, 31C Control part 32 Display part 42 Simultaneous counting part 43, 43A Cardiopulmonary synchronization data extraction part 44, 44A, 44B, 44C Image generating unit 52 Heart 61 Heart region specifying unit

Claims (6)

A plurality of detectors for detecting gamma rays emitted from the radioisotope administered to the subject;
A data collection unit that collects output data of a respiratory sensor and an electrocardiographic sensor attached to the subject, and output data of the plurality of detectors;
Based on the data collected by the data collection unit, an image is generated based on the output data of the plurality of detectors in the first period in which the cardiac motion is in the same phase period and the heart motion is smaller than the threshold value. An image generation unit to
Based on the output data of the plurality of detectors, a heart region specifying unit for specifying data derived from the heart region from the detection time difference of the pair annihilation gamma ray pair;
Equipped with a,
The image generation unit
The output data of the plurality of detectors in the first period and the in-phase period of the respiratory motion and in a predetermined number of periods among a plurality of second periods in which the heart motion is greater than the threshold By deleting data derived from the heart region from the output data of the plurality of detectors, data derived from the heart region is thinned out from the output data of the plurality of detectors in the plurality of second periods. Image based on the collected data,
Nuclear medicine diagnostic equipment. The plurality of detectors are:
Detecting pair annihilation gamma rays originating from at least the lung field region of the subject and the heart region;
The image generation unit
In the lung field region of the output data of the plurality of detectors in the first period, the data subjected to position filtering with a predetermined intensity, and the output data of the plurality of detectors in the second period A position filter is applied to the derived data at the predetermined intensity, while an image is generated based on the data obtained by applying the position filter at an intensity different from the predetermined intensity for the data derived from the heart region. Generate,
The nuclear medicine diagnostic apparatus according to claim 1 . Based on the output data of the plurality of detectors, a heart region specifying unit that specifies data derived from the heart region from the detection time difference of the pair annihilation gamma ray pair;
Further comprising
The plurality of detectors are:
Detecting pair annihilation gamma rays originating from at least the lung field region of the subject and the heart region;
The image generation unit
The data obtained by applying a position filter to the output data of the plurality of detectors at a predetermined intensity in the first period and the in-phase period of the respiratory motion and the period in which the heart motion is greater than the threshold value Among the output data of the plurality of detectors in the second period, the position filter is applied to the data derived from the lung field region at the predetermined intensity, while the data derived from the heart region is applied to the predetermined data. Generate an image based on the data that has been subjected to position filtering at an intensity different from the intensity of
The nuclear medicine diagnostic apparatus according to claim 1. The position filter is a Gaussian filter, and the intensity is a variance value of a Gaussian function used in the Gaussian filter.
The nuclear medicine diagnostic apparatus according to claim 2 or 3 . The data collection unit
Based on the output data of the plurality of detectors, data is collected in a list mode for acquiring information on the energy and incident time of the incident gamma rays every time gamma rays are incident on the detectors.
The nuclear medicine diagnostic apparatus according to any one of claims 1 to 4 . On the computer,
Based on the output data of a plurality of detectors that detect gamma rays emitted from the radioisotope administered to the subject and the output data of the respiratory sensor and the electrocardiographic sensor attached to the subject, the respiratory motion is the same. Extracting output data of the plurality of detectors in a first period that is a phase period and wherein the heart motion is less than a threshold;
Identifying data derived from the heart region from the detection time difference of the pair of annihilation gamma rays based on the output data of the plurality of detectors;
From the output data of the plurality of detectors in a predetermined number of periods among the plurality of second periods in which the respiratory motion is the same phase period and the heart motion is greater than the threshold value, derived from the heart region Generating data obtained by thinning out data derived from the heart region from output data of the plurality of detectors in the plurality of second periods by deleting data to be
Based on output data of the plurality of detectors in the first period and data obtained by thinning out data derived from the heart region from output data of the plurality of detectors in the plurality of second periods. Generating an image; and
An image processing program for executing

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