WO2018133412A1 - 一种用于pet系统的时间校正装置 - Google Patents

一种用于pet系统的时间校正装置 Download PDF

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WO2018133412A1
WO2018133412A1 PCT/CN2017/099237 CN2017099237W WO2018133412A1 WO 2018133412 A1 WO2018133412 A1 WO 2018133412A1 CN 2017099237 W CN2017099237 W CN 2017099237W WO 2018133412 A1 WO2018133412 A1 WO 2018133412A1
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module
time
ring
data
pet system
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PCT/CN2017/099237
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English (en)
French (fr)
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牛明
刘彤
谢庆国
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苏州瑞派宁科技有限公司
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Priority to JP2019555529A priority Critical patent/JP6801906B2/ja
Priority to EP17892689.5A priority patent/EP3549526B1/en
Priority to US16/479,880 priority patent/US11280921B2/en
Publication of WO2018133412A1 publication Critical patent/WO2018133412A1/zh

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/42—Arrangements for detecting radiation specially adapted for radiation diagnosis
    • A61B6/4208—Arrangements for detecting radiation specially adapted for radiation diagnosis characterised by using a particular type of detector
    • A61B6/4258—Arrangements for detecting radiation specially adapted for radiation diagnosis characterised by using a particular type of detector for detecting non x-ray radiation, e.g. gamma radiation
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/02—Arrangements for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
    • A61B6/03—Computed tomography [CT]
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/02—Arrangements for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
    • A61B6/03—Computed tomography [CT]
    • A61B6/032—Transmission computed tomography [CT]
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/02—Arrangements for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
    • A61B6/03—Computed tomography [CT]
    • A61B6/037—Emission tomography
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/42—Arrangements for detecting radiation specially adapted for radiation diagnosis
    • A61B6/4208—Arrangements for detecting radiation specially adapted for radiation diagnosis characterised by using a particular type of detector
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/42—Arrangements for detecting radiation specially adapted for radiation diagnosis
    • A61B6/4266—Arrangements for detecting radiation specially adapted for radiation diagnosis characterised by using a plurality of detector units
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/42—Arrangements for detecting radiation specially adapted for radiation diagnosis
    • A61B6/4275—Arrangements for detecting radiation specially adapted for radiation diagnosis using a detector unit almost surrounding the patient, e.g. more than 180°
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/44—Constructional features of apparatus for radiation diagnosis
    • A61B6/4411—Constructional features of apparatus for radiation diagnosis the apparatus being modular
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/54—Control of apparatus or devices for radiation diagnosis
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/58—Testing, adjusting or calibrating thereof
    • A61B6/582—Calibration
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/58—Testing, adjusting or calibrating thereof
    • A61B6/582—Calibration
    • A61B6/585—Calibration of detector units
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/29—Measurement performed on radiation beams, e.g. position or section of the beam; Measurement of spatial distribution of radiation
    • G01T1/2914—Measurement of spatial distribution of radiation
    • G01T1/2985—In depth localisation, e.g. using positron emitters; Tomographic imaging (longitudinal and transverse section imaging; apparatus for radiation diagnosis sequentially in different planes, steroscopic radiation diagnosis)

Definitions

  • the present invention relates to a time correction device in the field of medical devices, and more particularly to a time correction device for a PET system.
  • Positron Emission Tomography (PET) system is a non-invasive functional metabolic molecular imaging device. The principle is as follows: radionuclide decay produces positrons, and positron motion is short. After a distance (usually a few millimeters), it will annihilate with the electrons in the tissue, and its mass will be converted into a pair of gamma photons with an energy of 0.511 MeV, which will be emitted in the opposite direction, which will be labeled on the molecular probe.
  • the positron nuclides act as tracers to detect the time, energy and position information of the gamma photons generated by positron annihilation, and use the conforming technique to obtain the annihilation event response line (also referred to as LOR, Line of Response), and then adopt The image reconstruction algorithm is imaged to reflect the degree of ingestion of the tracer at each site, thereby assisting the doctor in making relevant diagnoses for the disease.
  • LOR Line of Response
  • the time resolution is an important indicator of the PET system. It characterizes the uncertainty of the arrival of a pair of gamma photons after the annihilation event in the PET system, also known as response fluctuation. From the definition of time resolution, we can know that in the detector design using crystal array, the response line will increase accordingly. Each response line corresponds to a time spectrum. The time spectrum corresponding to many response lines is combined into the time spectrum of the basic unit module.
  • the time correction method adopted by most PETs in the prior art is the direct measurement correction method
  • the classical direct measurement correction method is the rotary rod source time correction method.
  • the rotating rod source time correction method utilizes the rod source used in the transmission scanning while performing the circular motion of the attenuation correction around the detector ring. Calibration of time information is performed in accordance with data acquisition and iterative processing (see Williams J, Luo D, KL M, et al. Crystal-based coincidence timing calibration method, United State Patent 7030382, Apr., 2006). Utilizing the attenuation correction rod source in classic PET, calibration can be done without the need for additional equipment for classic clinical PET instruments. The introduction of PET/CT is becoming more and more popular in the market today.
  • PET/CT directly uses the density information of the imaging tissue reflected by CT imaging as reference, thus generating the attenuation factor required for PET attenuation correction, so that most new instruments are no longer dependent on attenuation correction. Rotating the rod source further makes the method also challenged in the PET/CT state.
  • Rotating rod source time correction method mostly uses iterative algorithm, the basic data amount is large, the algorithm complexity is high, the algorithm complexity is O(n 2 ), O(n 2 ) is the square order, here refers to the number of statement executions in the algorithm, n is the basic unit, which can also be understood as the number of crystal lattices.
  • the iterative algorithm takes longer to calculate the final result.
  • the source of the rotating rod is generally 68-Ge.
  • the half-life of the source is 270.95 days. After a certain time, the user needs to replace the Ge source, which directly increases the operating cost of the PET.
  • the correction device used is relatively simple, only a small response line, that is, a ring, can be involved in the correction.
  • the time information correction on the upper part of the response line does not cover all the response lines in the full field of view FOV (Field of View); and when using the larger diameter of the source cylindrical prosthesis, it is sufficient
  • FOV Field of View
  • the time distribution information on the multi-response line due to its large volume, the time distribution of most of the response lines will become more diffuse, increasing the full width at half maximum of the time distribution, and not being able to accurately correct all the response lines in the field of view. Time offset.
  • the correction unit is mainly a basic module and is not accurate to the minimum basic unit "crystal lattice".
  • the radioactive source used for the fixation is 68-Ge or 22-Na
  • the half-life of 68-Ge is 270 days
  • the -22 years of 22-Na after a certain period of time, the radioactive source must be replaced if it is desired to maintain the performance of the PET system. .
  • the technical solution of the present invention is to provide a time correction device for a PET system, the time correction device comprising: a detector ring, the detector ring comprising a plurality of sequentially arranged detectors; a prosthesis, the ring prosthesis is located in the detector ring, a center of the ring prosthesis coincides with an axial and radial center of the detector ring; a detection module, the detection module is located a ring prosthesis, and a center of the detecting module is located at a center of the ring prosthesis; a data acquiring module, the data acquiring module includes a data collecting module and an energy screening module connected to each other, and the data collecting module Including the detector and the detecting module, the energy screening module is connected to the data collecting module and receives a single event sent by the data collecting module Time information, the data conforms to the module, the data conforming module is connected to the energy screening module and receives single event time information sent by the energy screening module; a time offset value calculating
  • the axial length of the annular prosthesis does not exceed the axial length of the detector ring, and the outer diameter of the annular prosthesis does not exceed the inner diameter of the detector ring.
  • the inner diameter of the annular prosthesis is between half of the diameter of the detector ring and the outer diameter of the detection module.
  • the thickness of the ring prosthesis is uniform.
  • the ring prosthesis has a source, and the activity of the source satisfies the condition that the overall counting rate of the PET system after placing the source is at least twice the counting rate of the PET system during the empty sweep.
  • the activity of the source in the ring pseudo-injection is 30 to 500 uCi.
  • the temporal resolution of the detection module is higher than the temporal resolution of the detector on the detector ring.
  • the detection module is a high-time performance detection module with a time resolution of less than 1 ns.
  • the detecting module includes a strontium silicate scintillation crystal, a photoelectric conversion device, and an electronic readout portion coupled to the photoelectric conversion device, the photoelectric conversion device and the electronic readout portion connection.
  • the photoelectric conversion device is one of a photomultiplier tube, a silicon photomultiplier tube, a multi-pixel photon counter, or a Geiger mode avalanche diode.
  • the data collection module obtains a list of single event time information by using the detector on the detector ring and the detection module, and the energy screening module performs an energy window on the single event time information collected by the data collection module. Analytical screening to filter out scattering events.
  • the invention adopts a ring prosthesis instead of using a rotating rod source, which greatly reduces the design of the PET system, controls the complexity of the PET system design, and is easy to operate when using the ring prosthesis for time correction operation.
  • the advantages are therefore better adapted to today's popular PET or PET/CT instruments.
  • the invention places the detecting module at the center of the field of view as the detector on the detector ring Inter-reference, through the same reference method, reduces the complexity of the algorithm.
  • the invention only needs to collect data once statically during calibration, and the algorithm is high-speed and simple and effective. Compared with the iterative optimization correction algorithm used in the existing methods, the complexity is greatly reduced and the operation time is reduced.
  • FIG. 1 is a schematic view showing the arrangement of a time correcting device for a PET system in accordance with a preferred embodiment of the present invention
  • FIG. 2 is a schematic structural diagram of a detecting module for a time correcting device of a PET system according to a preferred embodiment of the present invention
  • FIG. 3 is a flow chart showing a time correction device for a PET system in accordance with a preferred embodiment of the present invention
  • FIG. 4 is a system diagram of a time correction device for a PET system in accordance with a preferred embodiment of the present invention
  • Figure 5 is a timing diagram showing the time distribution of a time correction device for a PET system in accordance with a preferred embodiment of the present invention
  • FIG. 6 is a schematic diagram of a random coincidence comparison of a time correction device for a PET system in accordance with a preferred embodiment of the present invention, wherein a broken line indicates that no time correction is performed, and a solid line indicates that time correction is applied;
  • FIG. 7 is a comparison diagram of NECR curves for a time correction device for a PET system in which a broken line indicates that no time correction is performed and a solid line indicates that time correction is applied, in accordance with a preferred embodiment of the present invention.
  • FIG. 1 is a schematic view showing the arrangement of a time correction device for a PET system provided by the present invention, the time correction device comprising a detector ring 10, a ring prosthesis 20 and a detection module 30, wherein the detector ring 10 is composed of a plurality of detectors 11
  • the ring is sequentially arranged to form a ring.
  • the ring prosthesis 20 is located in the detector ring 10.
  • the center of the ring prosthesis 20 coincides with the axial and radial centers of the detector ring 10, and the detecting module 30 is located in the ring prosthesis 20.
  • the center of the detection module is located at the center of the detector ring 10 and the ring prosthesis 20.
  • the axial length of the annular prosthesis 20 does not exceed the axial length of the detector ring 10, the outer diameter of the annular prosthesis 20 does not exceed the inner diameter of the detector ring 10, and the inner diameter of the annular prosthesis 20 is not less than that of the detecting module 30. Outer diameter. More preferably, the inner diameter of the annular prosthesis 20 is between the half of the diameter of the detector ring 10 and the diameter of the detection module 30.
  • the annular prosthesis 20 has a uniform thickness and is not easily deformed. In order to avoid background and random noise interference, the ring prosthesis 20 needs to be injected into the source when performing calibration.
  • the activity of the source preferably satisfies the following condition, that is, the overall counting rate of the PET system after placing the source is at least PET system empty.
  • the sweep time count rate is about 2 times or more, more preferably 10 times.
  • the source of the ring prosthesis 20 is a liquid positive source of the PET system, such as 18 F-FDG based on 18 F, 18 F-FDOPA, 18 F-FLT, etc., based on 15 O 15 OH 2 O, based on 11 C
  • a radioactive positive source such as 11 C-sodium acetate or 11 C-choline. Since the activity required for the higher sensitivity of the instrument is lower, the activity of the source in the annular prosthesis 20 of the present invention is preferably 30 to 500 uCi, more preferably 300 to 500 uCi, which is low in cost and good in flexibility.
  • the shape of the detector ring 10 is circular, but the detector ring of the present invention is not limited to a toroidal shape, for different annular or even acyclic detectors.
  • the detector ring 10 can be in the form of a detector such as a flat plate, a quadrangle or an octagon.
  • the detection module 30 on the PET system of the present invention employs a high time performance detection module. It should be understood that if the time performance of the detection module 30 is better than the inherent time performance of the detector 11 on the detector ring 10, that is, the detection module The time resolution of 30 is higher than the time resolution of the detector 11 on the detector ring 10, and can be considered as a high time performance detection module in the present invention.
  • the time performance of the high temporal performance detection module in the present invention is less than 1 ns.
  • the detection module 30 itself is smaller than the annular prosthesis 20 and may be other shapes and not limited to a circular shape.
  • FIG. 2 is a schematic structural diagram of a detecting module 30 for a time correcting device of a PET system according to a preferred embodiment of the present invention, wherein the detecting module 30 includes a strontium silicate scintillation crystal 31 (abbreviated as LYSO crystal), and a photoelectric conversion device 32. And an electronic readout portion 33, the LYSO crystal 31 is coupled to the photoelectric conversion device 32, the photoelectric conversion device 32 is connected to the electronic readout portion 33, and the connection of the electronic readout portion 33 to the data acquisition portion (not shown) belongs to The common sense of the field is not repeated here.
  • the photoelectric conversion device 32 employs a photomultiplier tube (PMT), such as the Hamamatsu R9800 model used in the embodiment of FIG.
  • PMT photomultiplier tube
  • FIG. 3 is a flow of a time correction device for a PET system in accordance with a preferred embodiment of the present invention.
  • the schematic diagram of the time correction device of the present invention includes the following steps when used:
  • Step S1 placing and fixing the ring prosthesis 20 and the detecting module 30 containing the source in the detector ring 10;
  • Step S2 Initializing a time correction parameter in the PET system
  • Step S3 performing a compliance event acquisition of the system
  • Step S4 acquiring a time relative offset value of each crystal lattice
  • Step S5 updating and applying the system time correction parameter
  • the coincidence event acquisition in step S3 is specifically to obtain the coincidence events of the respective crystal lattices with respect to the central detection module 30, so as to at least obtain accurate time information and crystal lattice position information including the arrival of the event.
  • the crystal lattice in the detector is determined by the crystal array specification used in the detector design, and is not specifically limited herein.
  • the step S3 is different from the prior art in that not only the coincidence data of the probe ring 10 itself but also the coincidence data of the probe module 30 located at the center of the probe ring 10 are collected in the step S3 of the present invention.
  • step S4 the coincidence events obtained by the crystal lattices in the detector ring 10 with respect to the detection module 30 are consistent with the time distribution, and the time relative offset value t n is obtained therefrom, where n is the crystal lattice number and n is a positive integer. .
  • an iterative algorithm is used to correct the parameters.
  • the step S4 of the present invention uses a direct measurement calculation method to obtain a time offset value on each crystal lattice, thereby obtaining a correction parameter, and the algorithm is high-speed, simple, and effective. Large reduction in complexity and reduced computing time.
  • the relative time offset value t n of each crystal lattice time obtained in step S5 is applied to the system, and the specific method is to correct the time information in the original data when the single event is acquired, that is, subtract or add the original time information.
  • the obtained time is relative to the offset value t n , and specifically the deduction or addition is calculated according to the time relative offset value.
  • the system of the time correction device provided by the present invention includes a data acquisition module 100, a data compliance module 200, and a time offset.
  • the value calculation module 300 and the data correction application module 400 wherein the data acquisition module 100 includes a data acquisition module 110 and an energy screening module 120 connected to each other, and the energy screening module 120 is connected to the data compliance module 200 and transmits the collection to the data compliance module 200.
  • Single event time information is included in the data acquisition module 100, a data compliance module 200, and transmits the collection to the data compliance module 200.
  • the data acquisition module 100 is configured to acquire a single event time information of each detector on the detection module and the detector ring, and apply a power window to the single event time information to perform a partial preprocessing operation, wherein the data acquisition module 110 is configured to acquire the detection module.
  • the listed single event time information of each detector on the detector ring is transmitted and stored to the upper computer server for processing.
  • the energy screening module 120 is configured to perform an analysis and screening of a certain energy window on the original single event time information collected by the data collection module 110, and filter out the scattering event.
  • the data acquisition module 110 is the sum of the detectors and the detection module 30 on the detector ring 10, and the data acquisition module 110 acquires the detector 11 and the high performance detection module on the detector ring 10.
  • the generated single event time information is generated by the data collection module 110, and the data collection module 110 is connected to the energy screening module 120 to transmit and store the single event time information to the upper computer server for processing, and the energy screening module 120 in the upper computer server pairs the data.
  • the original single event time information collected by the acquisition module 110 is subjected to analysis and screening of a certain energy window to filter out the scattering event. It should be understood that the selection of the energy window can be determined by a person skilled in the art according to the needs of specific information collection, and details are not described herein again.
  • the sequence of the data acquisition module 110 and the energy screening module 120 in the data acquisition module 100 can be reversed in the time correction device of the present invention, that is, the energy screening module 120 can be integrated on the detector ring 10 In the detector 11 and the detecting module 30, the scattering event can be filtered out by the energy screening module 120 and then uploaded to the upper computer server through the data collecting module 110.
  • the source activity is relatively high, the data collection efficiency is higher in this mode.
  • the data conforming module 200 is configured to match the single event time information acquired by the data acquiring module 100 according to the set time window and other conditions, and obtain the matching data of each crystal lattice on each detector relative to the detecting module.
  • the energy screening module 120 sets several different screening ranges, such as 350-650 keV, 250-750 keV, etc., and the data conforming module 200 performs data conformance according to this, and obtains each crystal lattice of each detector on the detector ring 10.
  • the time offset value calculation module 300 is configured to perform time distribution acquisition on the coincidence data of each crystal lattice relative to the detection module, and obtain an offset value t n , where n is a crystal lattice number and n is a positive integer.
  • the data correction application module 400 is configured to apply the obtained offset values t n of the respective crystal lattices to the entire system, and perform time correction operations on the acquired time information in each single event. Specifically, the time information correction is performed on the offset value t n obtained by removing the time information in the list-type single event time information acquired by the data acquisition module 100. For the calculation of the offset value t n and the correction method, refer to step S5 above, and details are not described herein.
  • FIG. 5 is a timing diagram of a time correction device for a PET system in accordance with a preferred embodiment of the present invention, wherein a broken line e represents a time distribution of a system composed of all detectors on the detector ring 10 before time correction, and time resolution thereof.
  • the rate is 1.7 ns and the center value is 121.8 ps.
  • the solid line f represents the time distribution of all detector components after time correction.
  • the time resolution is 1.26 ns and the center value is -3.6 ps.
  • the time resolution of the present invention is more conducive to the implementation of TOF-PET (also known as time-of-flight PET technology) relative to the time resolution of 400-500 ps in the prior art.
  • FIGS. 6 and 7 are schematic diagram of random coincidence of the time correction device for the PET system according to a preferred embodiment of the present invention, wherein the dotted line Indicates that time correction is not performed, and solid line indicates that time correction is applied;
  • FIG. 7 is a comparison diagram of NECR curves for a time correction device for a PET system according to a preferred embodiment of the present invention, wherein a broken line indicates that time correction is not performed, and a solid line indicates Time correction is applied.
  • the random coincidence event decreases as the time window decreases.
  • the size of the time window is again set according to the temporal resolution, typically twice the time resolution.
  • the random coincidence event is less reflected in the final imaging, which is an improvement in image quality (signal-to-noise ratio).
  • the NECR curve was tested by the NECR prosthesis according to the method in the NEMA-NU4 standard. It can be seen from Fig. 6 that the random coincidence distribution after the time correction application is lower than before the correction, and in Fig. 7, it can be seen that the correction is true before and after the correction. NECR has a big improvement in the case of no change in the event. The improvement can be seen in Figure 6. The count rate is nearly doubled over the entire activity range.
  • the invention adopts the ring prosthesis instead of using the rotating rod source, which greatly reduces the design of the PET system, controls the complexity of the PET system design, and has a simple operation when using the ring prosthesis for time correction operation.
  • the advantages are therefore better adapted to today's popular PET or PET/CT instruments.
  • the invention introduces a detecting module, in particular, the high time performance detecting module is placed in the center of the field of view as a time reference of the detector on the detector ring, and the complexity of the algorithm is reduced by the same reference method.
  • the invention only needs to collect data once statically during calibration, and it can be known that the time complexity at this time is O(n), where n is the total number of crystal lattices on the detector ring.
  • the algorithm is fast and efficient, and it reduces the complexity and reduces the computation time compared with the iterative optimization correction algorithm used in the existing methods.
  • the invention can also make crystal time for the smallest detection unit on the detector ring, that is, the small crystal lattice Correction. By combining the calculation methods, the calculation correction efficiency can be improved.
  • the structure of the detecting module 30 in the present invention may be For crystal/photoelectric conversion device/electronic readout, it can also be crystal/photoconductive/photoelectric and conversion device/electronic readout, or photoelectric conversion device/electronic readout CZT detector; and again, for example, the present invention crystal high performance time detector module may be used LaBr 3, LSO, LYSO, LuYAP , BaF 2, GSO, LFS LuI 3 or other species, may be cylindrical in shape, elongated, tapered square and other
  • the photoelectric conversion device used in the high time performance detecting module of the present invention may be a photomultiplier tube, a silicon photomultiplier (SiPM), a multi-pixel photon counter (MPPC), A Geiger-mode avalanche photodiode (G-APD) or the

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Abstract

一种用于PET系统的时间校正装置包括探测器环(10)、圆环假体(20)、探测模块(30)、数据获取模块(100)、数据符合模块(200)、时间偏移值计算模块(300)和数据校正应用模块(400)，圆环假体(20)的圆心与探测器环(10)的轴向及径向中心重合，探测模块(30)位于圆环假体(20)内，探测模块(10)的中心位于圆环假体(20)的中心位置，数据获取模块(100)包括相互连接的数据采集模块(110)和能量筛选模块(120)，数据采集模块(110)包括探测器(11)和探测模块(30)，能量筛选模块(120)与数据采集模块(110)连接并接收数据采集模块(110)发送的单事件时间信息，数据符合模块(200)与能量筛选模块(120)连接并接收单事件时间信息，时间偏移值计算模块(300)与数据符合模块(200)连接以得出探测器(11)的偏移值，数据校正应用模块(400)用于将偏移值应用于整个系统。该装置减小了PET系统时间校正时算法的复杂度，操作简便，降低了PET系统的运营成本。

Description

一种用于PET系统的时间校正装置 技术领域
本发明涉及医疗器械领域中的一种时间校正装置，更具体地涉及一种用于PET系统的时间校正装置。
背景技术
正电子发射计算机断层成像(Positron Emission Tomography，以下简称PET)系统是一种非侵入性的功能代谢分子影像设备，它采用的原理如下：放射性核素衰变会产生正电子，正电子运动很短的一段距离(通常为几个毫米)后就会与组织中的电子结合而发生湮灭，其质量转化成一对向相反方向射出的能量均为0.511MeV的伽马光子，将标记于分子探针上的正电子核素作为示踪剂，通过探测获取正电子湮灭所产生的伽马光子的时间、能量和位置信息，运用符合技术得到湮灭事件响应线(也简称为LOR，Line of Response)，然后采用图像重建算法成像以反映各部位对示踪剂的摄取程度，进而辅助医生对疾病做出相关诊断。
符合时间分辨率是PET系统的一个重要指标，它表征了PET系统中湮灭事件发生后一对伽马光子到达的不确定度，又称为响应波动。从符合时间分辨率的定义中我们可以知道，在采用晶体阵列的探测器设计中，其响应线会相应的增多。每一条响应线对应着一个时间谱。诸多响应线对应的时间谱组合成了基本单元模块的时间谱。由于晶体阵列中各个晶体条之间存在均一性误差，即晶体阵列中各个晶体条的性能差异(包括光输出、衰减时间常数、光子渡过时间等)，以及光电转换器件区域非线性关系，使得所有时间谱的中心值都不是准确的处在理想中的零时刻，因此，基本单元模块的时间谱的展宽会被拓宽。
现有技术中大多数PET采用的时间校正方法为直接测量校正法，比较经典的直接测量校正法为旋转棒源时间校正法。旋转棒源时间校正法利用透射扫描时使用的棒源，在环绕探测器环进行衰减校正的圆周运动的同时，进行 符合数据的采集以及迭代处理等操作来进行时间信息的校正(参见Williams J,Luo D,K.L M，et al.Crystal-based coincidence timing calibration method,United State Patent 7030382,Apr.,2006)，该方法利用了经典PET中的衰减校正棒源，对于经典临床PET仪器而言不需要加入额外的装置便可以完成校正。现今市面上逐渐流行PET/CT的引进，PET/CT直接以CT成像反映的成像组织的密度信息为参考，从而生成PET衰减校正需要的衰减因子，使得大多新仪器在进行衰减校正时不再依赖旋转棒源，进一步使得该方法在PET/CT状态下的使用也面临了一定的挑战。
还有一些直接测量校正法通过在探测器环中心放置实心线源、棒源或者注射示踪剂的圆柱假体或圆环假体进行数据采集后，再使用迭代计算的方法进行时间校正(参见Willians J.Automated coincidence timing calibration for a pet scanner,United States Patent 5272344,Dec.,1993)(Xiaoli Li,Burr,K.C,Gin-Chung Wang,Huini Du,etc.Timing calibration for time-of-flight PET using positron-emitting isotopes and annihilation targets,IEEE Nucl.Sci.Symp.Conf.Rec.,pp.1-5,2013)。当使用线源、柱源或者注射示踪剂的直径较小的圆柱假体时，其在进行时间校正时只能涉及到较少响应线，即在圆环上的部分探测器上进行了时间信息校正；而当使用直径较大的射源圆柱假体时，在获取足够多响应线上的时间分布信息的同时，由于其体积较大，大多响应线上的时间分布会变得较为扩散，其中心偏移时刻的确认存在较大的误差。
另外，从系统的复杂程度角度而言，旋转棒源时间校正法中棒源的旋转需要使用额外的机械传动装置，比如用马达带动控制调整棒源的位置，实现精准调控，在机械部件的设计和实现上有着一定难度，增加了整个PET系统的复杂度。旋转棒源时间校正法大多使用迭代算法，基础数据量大，算法复杂度高，算法复杂度为O(n2)，O(n2)为平方阶，在此指算法中的语句执行次数，n为每一个基本单元，也可理解为晶体格的个数，该迭代算法求得最终结果的运算时间较长。旋转棒源一般采用68-Ge，该放射源的半衰期是270.95天，一定时间后用户需要重新更换Ge源，直接增大了PET的运营成本。
而当使用线源、柱源或注射示踪剂的直径较小的圆柱假体作为校正基础时，虽然使用的校正装置比较简单，但在校正时只能涉及到较少响应线，即圆环上部分响应线上进行了时间信息校正，并不能覆盖全视场FOV(Field of View)内的所有响应线；而当使用直径较大的射源圆柱假体时，在获取足够 多响应线上的时间分布信息的同时，由于其体积较大，大多响应线上的时间分布会变得较为扩散，加大了时间分布的半高宽，不能够精确校正视场内所有响应线的时间偏移。
还有一些PET系统使用了圆环假体放在探测器环中心，但是同旋转棒源方法类似，使用了复杂的迭代算法得到最终的校正结果，采集时间虽然短，但是运算复杂度高，为O(n2)，运算时间较长。实际应用中为了提高运算速度，需要额外配备高性能计算服务器，增大了PET系统的成本。
除了上述的方法，还有一种采用时间探针的方法进行时间校正，其将射源与晶体固定在一起，置于FOV正中心，以此为基准来获取其与每一个模块的时间偏差值，但是其校正单元主要为基本模块，并未精确到最小基本单元“晶体格”。而且其固定所使用的放射源为68-Ge或22-Na，68-Ge的半衰期为270天，而22-Na的2.6年，一定的时间后若想保持PET系统的性能就必须更换放射源。
综上所述可知，现有技术中对PET系统进行时间校正时存在校正效果不彻底、算法复杂化、设备成本高等问题。因此，寻找一种效果优良、运算简单快捷，算法复杂度低且低成本的时间校正方法是当今PET系统所急需的。
发明内容
本发明的目的是提供一种用于PET系统的时间校正装置，从而解决现有技术中PET系统进行时间校正时校正效果不彻底、算法复杂化以及设备成本高的问题。
为了解决上述技术问题，本发明的技术方案是提供一种用于PET系统的时间校正装置，该时间校正装置包括：探测器环，所述探测器环包括若干依序排列的探测器；圆环假体，所述圆环假体位于所述探测器环内，所述圆环假体的圆心与所述探测器环的轴向及径向中心重合；探测模块，所述探测模块位于所述圆环假体内，并且所述探测模块的中心位于所述圆环假体的中心位置；数据获取模块，所述数据获取模块包括相互连接的数据采集模块和能量筛选模块，所述数据采集模块包括所述探测器和所述探测模块，所述能量筛选模块与所述数据采集模块连接并接收所述数据采集模块发送的单事件 时间信息，数据符合模块，所述数据符合模块与所述能量筛选模块连接并接收所述能量筛选模块发送的单事件时间信息；时间偏移值计算模块，所述时间偏移值计算模块与所述数据符合模块连接，所述时间偏移值计算模块通过所述单事件时间信息得出所述探测器的偏移值，以及数据校正应用模块，所述数据校正应用模块用于将得到的所述偏移值应用于整个系统，从而对所述单事件时间信息进行校正。
圆环假体的轴向长度不超过所述探测器环的轴向长度，所述圆环假体的外径不超过所述探测器环的内径。
圆环假体的内径大小介于所述探测器环直径的一半和所述探测模块的外径之间。
圆环假体的厚度均匀。
圆环假体内具有射源，所述射源的活度满足条件，即放置射源后PET系统的总体计数率至少为PET系统空扫时计数率的2倍。
圆环假体内射源的活度为30～500uCi。
探测模块的时间分辨率高于所述探测器环上所述探测器的时间分辨率。
探测模块为时间分辨率小于1ns的高时间性能探测模块。
探测模块包括硅酸钇镥闪烁晶体、光电转换器件以及电子学读出部分，所述硅酸钇镥闪烁晶体晶体与所述光电转换器件耦合，所述光电转换器件与所述电子学读出部分连接。
光电转换器件为光电倍增管、硅光电倍增管、多像素光子计数器或者盖革模式雪崩二极管中的一种。
数据采集模块通过所述探测器环上的探测器和所述探测模块获取列表式的单事件时间信息，所述能量筛选模块对所述数据采集模块采集到的所述单事件时间信息进行能量窗的解析筛选，滤除掉散射事件。
本发明采用圆环假体而非使用旋转棒源，在很大程度上减小了PET系统的设计，控制了PET系统设计的复杂度，使用圆环假体进行时间校正操作时还有着操作简便的优点，因此可以更好的适应当今流行的PET或者是PET/CT仪器。本发明将探测模块置于视场中心作为探测器环上探测器的时 间参考，通过同一参照的方法，降低了算法的复杂度。本发明在校正时只需静态采集一次数据，算法高速简洁有效，相对于现有方法中大量使用的迭代优化校正算法，极大的降低了复杂度，减少了运算时间。
附图说明
图1是根据本发明一个优选实施例的用于PET系统的时间校正装置的布置示意图；
图2是根据本发明一个优选实施例的用于PET系统的时间校正装置的探测模块结构示意图；
图3是根据本发明一个优选实施例的用于PET系统的时间校正装置的流程示意图；
图4是根据本发明一个优选实施例的用于PET系统的时间校正装置的系统示意图；
图5是根据本发明一个优选实施例的用于PET系统的时间校正装置的时间分布示意图；
图6是根据本发明一个优选实施例的用于PET系统的时间校正装置的随机符合对比示意图，其中虚线表示未进行时间校正，实线表示应用了时间校正；
图7是根据本发明一个优选实施例的用于PET系统的时间校正装置的NECR曲线对比示意图，其中虚线表示未进行时间校正，实线表示应用了时间校正。
具体实施方式
以下结合具体实施例，对本发明做进一步说明。应理解，以下实施例仅用于说明本发明而非用于限制本发明的范围。
图1为本发明提供的用于PET系统的时间校正装置的布置示意图，该时间校正装置包括探测器环10、圆环假体20和探测模块30，其中，探测器环10由若干探测器11依序排列形成圆环，圆环假体20位于探测器环10内，圆环假体20的圆心与探测器环10的轴向及径向中心重合，探测模块30位于圆环假体20内并且探测模块的中心位于探测器环10和圆环假体20的中 心位置。圆环假体20的轴向长度不超过探测器环10的轴向长度，圆环假体20的外径不超过探测器环10的内径，圆环假体20的内径不小于探测模块30的外径。更优选地，圆环假体20的内径介于探测器环10直径的一半和探测模块30的直径之间。圆环假体20的厚度均匀且不易变形。为避免背景和随机的噪声干扰，圆环假体20在进行校正时需要注入射源，射源的活度优选地满足以下条件，即放置射源后PET系统的总体计数率至少为PET系统空扫时计数率的2倍左右或者更高，更优选地为10倍。圆环假体20内射源为PET系统常用的液体状正子源，例如基于18F的18F-FDG、18F-FDOPA、18F-FLT等，基于15O的15O-H2O、基于11C的11C-乙酸钠、11C-胆碱等放射性正子源。由于仪器灵敏度越高所需的活度越低，本发明中圆环假体20内射源的活度优选为30～500uCi，更优选地为300～500uCi，其成本低、灵活性好。
在图1所示的实施例中，探测器环10的形状采用的是圆环形，但本发明的探测器环并不局限于圆环形状，对于不同的环状甚至是非环状的探测器同样适用，比如，探测器环10可采用平板状、四边形或者八边形等探测器排布形式。本发明的PET系统上探测模块30采用的是高时间性能探测模块，应当理解的是，若探测模块30的时间性能优于探测器环10上的探测器11的固有时间性能，也即探测模块30的时间分辨率高于探测器环10上探测器11的时间分辨率，在本发明中均可认定为高时间性能探测模块。同时，由于临床上各种PET仪器的时间分辨率存在一定的差异，在本发明中高时间性能探测模块的时间性能小于1ns。另外，相比圆环假体20，探测模块30自身较小，可以为其他形状而不局限于圆形。
图2是根据本发明一个优选实施例的用于PET系统的时间校正装置的探测模块30的结构示意图，其中，探测模块30包括硅酸钇镥闪烁晶体31(简称LYSO晶体)、光电转换器件32以及电子学读出部分33，LYSO晶体31与光电转换器件32耦合，光电转换器件32连接电子学读出部分33，电子学读出部分33与数据采集部分(图中未示)的连接属于本领域的公知常识，在此不再赘述。在本发明的优选实施例中，光电转换器件32采用光电倍增管(photomultiplier tube，PMT)，比如图2的实施例中采用的是滨松R9800型。
图3为根据本发明一个优选实施例的用于PET系统的时间校正装置的流 程示意图，本发明的时间校正装置在使用时，包括以下步骤：
步骤S1:在探测器环10中放置并固定含有射源的圆环假体20和探测模块30；
步骤S2:初始化PET系统中的时间修正参数；
步骤S3:进行系统的符合事件获取；
步骤S4:获取各晶体格的时间相对偏移值；
步骤S5:更新并应用系统时间修正参数；其中，
步骤S3中的符合事件获取具体为获取各个晶体格相对于中心的探测模块30的符合事件，从而至少获取包含事件到达的准确时间信息和晶体格位置信息。应当理解的是，探测器中的晶体格是由探测器设计中所采用的晶体阵列规格决定的，在此不做具体限定。步骤S3与现有技术的不同之处在于，本发明的步骤S3中不仅采集了探测器环10本身的符合数据，而且采集了探测器环10叠加位于中心的探测模块30的符合数据。
步骤S4中由探测器环10中的各晶体格相对于探测模块30得到的符合事件获取符合时间分布，并从中得出时间相对偏移值tn，其中n为晶体格编号，n为正整数。传统技术中使用迭代算法进行校正参数的方法相比，本发明的步骤S4使用的是直接测量计算的方法获得每一个晶体格上的时间偏移值，进而得到校正参数，算法高速简洁有效，极大的降低了复杂度，减少了运算时间。
步骤S5中将得到的各晶体格时间相对偏移值tn应用于系统中，具体方法为在单事件获取时对原始数据中的时间信息进行修正，即在原始的时间信息中扣除或添加上得到的时间相对偏移值tn，而具体采取扣除或者添加取决于时间相对偏移值的计算方式。时间相对偏移值的计算方式有两种，第一种是t中心-t圆环，此时校正计算为添加时间相对偏移值tn；第二种是t圆环-t中心，此时校正计算为扣除时间相对偏移值tn。
图4为根据本发明一个优选实施例的用于PET系统的时间校正装置的系统示意图，由图4可知，本发明提供的时间校正装置的系统包括数据获取模块100、数据符合模块200、时间偏移值计算模块300以及数据校正应用模块400，其中，数据获取模块100包括相互连接的数据采集模块110和能量筛选模块120，能量筛选模块120与数据符合模块200连接并向数据符合模块200传递采集到的单事件时间信息。
数据获取模块100用于获取探测模块和探测器环上各探测器的单事件时间信息，并对该单事件时间信息应用能量窗进行部分预处理操作，其中，数据采集模块110用于获取探测模块和探测器环上各探测器的列表式的单事件时间信息，传输并存储至上位机服务器留待处理。能量筛选模块120用于对数据采集模块110采集到的原始的单事件时间信息进行一定能量窗的解析筛选，滤除掉散射事件。例如，在图1的实施例中，数据采集模块110为探测器环10上的各探测器和探测模块30的总和，数据采集模块110获取探测器环10上的探测器11和高性能探测模块30生成的列表式的单事件时间信息，数据采集模块110通过与能量筛选模块120连接，将上述单事件时间信息传输并存储至上位机服务器留待处理，上位机服务器中的能量筛选模块120对数据采集模块110采集到的原始的单事件时间信息进行一定能量窗的解析筛选，滤除掉散射事件。应当理解的是，对于能量窗的选择，本领域技术人员可以根据具体信息采集的需要进行确定，在此不再赘述。
需要注意的是，数据获取模块100中的数据采集模块110和能量筛选模块120的前后顺序在本发明的时间校正装置中可以对调，即可以将能量筛选模块120集成于探测器环10上的各探测器11和探测模块30中，从而可以先通过能量筛选模块120将散射事件滤除，然后再通过数据采集模块110上传到上位机服务器。当射源活动比较高时，该模式下数据采集效率更高。
数据符合模块200用于将数据获取模块100获取到的单事件时间信息根据设定时间窗及其他条件进行数据符合，得到每一个探测器上每一个晶体格相对于探测模块的符合数据。比如，能量筛选模块120设定几个不同的筛选范围，例如350-650keV，250-750keV等，数据符合模块200据此进行数据符合，得到探测器环10上每一个探测器的每一个晶体格对应于高时间性能探测模块30的符合数据。
时间偏移值计算模块300用于对每一个晶体格相对于探测模块的符合数据进行时间分布获取，并得出其偏移值tn，其中n为晶体格编号，n为正整数。
数据校正应用模块400用于将得到的各个晶体格的偏移值tn应用于整个系统，对获取到的每一个单事件中的时间信息进行时间校正操作。具体为对数据获取模块100获取的列表式的单事件时间信息中的时间信息去除所获得的偏移值tn进行时间信息修正。偏移值tn的计算方式以及校正方式参见上文 步骤S5，在此不再赘述。
图5是根据本发明一个优选实施例的用于PET系统的时间校正装置的时间分布示意图，其中，虚线e表示时间校正前探测器环10上所有探测器组成的系统的时间分布，其时间分辨率为1.7ns，中心值为121.8ps；实线f表示时间校正后所有探测器组成系统的时间分布，其时间分辨率为1.26ns，中心值为-3.6ps。相对于现有技术中的400-500ps的符合时间分辨率，本发明的时间分辨率更有助于TOF-PET技术(time-of-flight PET，也称为飞行时间PET技术)的实现。
实现系统时间校正前后的随机符合以及NECR曲线分布分别如图6，7所示，其中，图6是根据本发明一个优选实施例的用于PET系统的时间校正装置的随机符合对比示意图，其中虚线表示未进行时间校正，实线表示应用了时间校正；图7是根据本发明一个优选实施例的用于PET系统的时间校正装置的NECR曲线对比示意图，其中虚线表示未进行时间校正，实线表示应用了时间校正。随机符合事件会随着时间窗口的减小而减小，时间窗口的大小又是根据时间分辨率来进行设定的，一般为时间分辨率的两倍。随机符合事件少反映在最终成像上就是图像质量(信噪比)有提升。NECR曲线通过NECR假体按照NEMA-NU4标准中的方法测试得出，从图6中可以看出时间校正应用后随机符合分布较校正前有降低，且在图7中可以看出校正前后在真事件没怎么变化的情况下NECR有了一个较大的提升，提升幅度可从图6中看出，在整个活度范围下计数率减小了近一倍。
本发明采用圆环假体而非使用旋转棒源在很大程度上减小了PET系统的设计，控制了PET系统设计的复杂度，使用圆环假体进行时间校正操作时还有着操作简便的优点，因此可以更好的适应当今流行的PET或者是PET/CT仪器。
本发明引入了一个探测模块，尤其是高时间性能探测模块置于视场中心作为探测器环上探测器的时间参考，通过同一参照的方法，降低了算法的复杂度。本发明在校正时只需静态采集一次数据，并且可以得知此时的时间复杂度为O(n)，n为探测器环上总的晶体格的数目。算法高速简洁有效，相对于现有方法中大量使用的迭代优化校正算法，极大的降低了复杂度，减小了运算时间。
本发明还可以针对探测器环上的最小探测单元，即小晶体格做晶体时间 校正。综合其计算方法，可以提高运算校正效率。
以上所述的，仅为本发明的较佳实施例，并非用以限定本发明的范围，本发明的上述实施例还可以做出各种变化，例如，本发明中的探测模块30的结构可以为晶体/光电转换器件/电子学读出，也可以为晶体/光导/光电和转换器件/电子学读出，或者是光电转换器件/电子学读出CZT探测器；再再比如，本发明的高时间性能探测模块所使用的晶体可以是LaBr3、LSO、LYSO、LuYAP、BaF2、GSO、LFS或者LuI3等多种种类，其形状可以为圆柱形，长条形，锥形方形等多种形状；再比如，本发明中高时间性能探测模块所使用的光电转换器件可以为光电倍增管、硅光电倍增管(silicon photomultiplier,SiPM)、多像素光子计数器(multi-pixel photon counter,MPPC)、盖革模式雪崩二极管(Geiger-mode avalanche photodiode，G-APD)等，只要渡越时间分布TTS小于500ps都可以作为本发明中的光电转换器件。总之，凡是依据本发明申请的权利要求书及说明书内容所作的简单、等效变化与修饰，皆落入本发明专利的权利要求保护范围。

Claims (10)

  1. 一种用于PET系统的时间校正装置，其特征在于，所述时间校正装置包括：
    探测器环，所述探测器环包括若干依序排列的探测器；
    圆环假体，所述圆环假体位于所述探测器环内，所述圆环假体的圆心与所述探测器环的轴向及径向中心重合；
    探测模块，所述探测模块位于所述圆环假体内，并且所述探测模块的中心位于所述圆环假体的中心位置；
    数据获取模块，所述数据获取模块包括相互连接的数据采集模块和能量筛选模块，所述数据采集模块包括所述探测器和所述探测模块，所述能量筛选模块与所述数据采集模块连接并接收所述数据采集模块发送的单事件时间信息，
    数据符合模块，所述数据符合模块与所述能量筛选模块连接并接收所述能量筛选模块发送的单事件时间信息；
    时间偏移值计算模块，所述时间偏移值计算模块与所述数据符合模块连接，所述时间偏移值计算模块通过所述单事件时间信息得出所述探测器的偏移值，以及
    数据校正应用模块，所述数据校正应用模块用于将得到的所述偏移值应用于整个系统，从而对所述单事件时间信息进行校正。
  2. 根据权利要求1所述的用于PET系统的时间校正装置，其特征在于，所述圆环假体的轴向长度不超过所述探测器环的轴向长度，所述圆环假体的外径不超过所述探测器环的内径。
  3. 根据权利要求2所述的用于PET系统的时间校正装置，其特征在于，所述圆环假体的内径大小介于所述探测器环直径的一半和所述探测模块的外径之间。
  4. 根据权利要求1所述的用于PET系统的时间校正装置，其特征在于，所述圆环假体的厚度均匀。
  5. 根据权利要求1所述的用于PET系统的时间校正装置，其特征在于，所述圆环假体内具有射源，含有射源的PET系统的总体计数率至少为PET系统空扫时计数率的2倍。
  6. 根据权利要求1所述的用于PET系统的时间校正装置，其特征在于，所述圆环假体内射源的活度为30～500uCi。
  7. 根据权利要求1所述的用于PET系统的时间校正装置，其特征在于，所述探测模块的时间分辨率高于所述探测器环上所述探测器的时间分辨率。
  8. 根据权利要求7所述的用于PET系统的时间校正装置，其特征在于，所述探测模块为时间分辨率小于1ns的高时间性能探测模块。
  9. 根据权利要求1所述的用于PET系统的时间校正装置，其特征在于，所述探测模块包括硅酸钇镥闪烁晶体、光电转换器件以及电子学读出部分，所述硅酸钇镥闪烁晶体晶体与所述光电转换器件耦合，所述光电转换器件与所述电子学读出部分连接。
  10. 根据权利要求9所述的用于PET系统的时间校正装置，其特征在于，所述光电转换器件为光电倍增管、硅光电倍增管、多像素光子计数器或者盖革模式雪崩二极管中的一种。
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111914393A (zh) * 2020-06-29 2020-11-10 上海联影医疗科技有限公司 死时间校正方法、装置、计算机设备和存储介质

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109323975B (zh) * 2018-11-07 2021-05-25 中国科学院合肥物质科学研究院 一种基于回波阈值比较的opc计数校正方法
WO2020211764A1 (en) * 2019-04-15 2020-10-22 Shanghai United Imaging Healthcare Co., Ltd. Systems and methods for determining true coincidence events
CN110133710B (zh) * 2019-04-24 2021-02-26 苏州瑞派宁科技有限公司 一种信号校正的方法及装置
CN112932515B (zh) * 2021-01-29 2022-06-21 明峰医疗系统股份有限公司 一种用于tof-pet的时间校正方法
CN112807009A (zh) * 2021-02-02 2021-05-18 上海联影医疗科技股份有限公司 放射源摆位方法、系统、设备、电子装置和存储介质

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5272344A (en) 1992-11-10 1993-12-21 General Electric Company Automated coincidence timing calibration for a pet scanner
US7030382B2 (en) 2002-10-31 2006-04-18 General Electric Company Crystal-based coincidence timing calibration method
US8089043B2 (en) * 2009-12-01 2012-01-03 Siemens Medical Solutions Usa, Inc. Systems and methods for calibrating time alignment for a positron emission tomography (PET) system
CN102783964A (zh) * 2012-07-02 2012-11-21 苏州瑞派宁科技有限公司 Pet成像中单事件列表式数据的同步方法及系统
CN103976755A (zh) * 2014-05-16 2014-08-13 沈阳东软医疗系统有限公司 一种时间补偿方法及装置
US20150065869A1 (en) * 2013-09-03 2015-03-05 Prescient Imaging LLC Low noise transmission scan simultaneous with positron emission tomography
CN104434160A (zh) * 2013-09-18 2015-03-25 上海联影医疗科技有限公司 Pet扫描装置及其时间偏移校正方法
CN104977601A (zh) * 2015-06-20 2015-10-14 明峰医疗系统股份有限公司 一种基于SiPM的PET系统的延时测算方法
CN106233336A (zh) * 2014-04-23 2016-12-14 皇家飞利浦有限公司 Pet 随机符合校正

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5935170A (ja) * 1982-08-23 1984-02-25 Shimadzu Corp ポジトロンｃｔ装置
JPS5999377A (ja) * 1982-11-30 1984-06-08 Shimadzu Corp ポジトロンｃｔ装置の調整装置
CN1062336A (zh) 1990-12-13 1992-07-01 邢世增 以砖瓦窑生产长效微量元素肥料
US7247844B2 (en) * 2002-11-07 2007-07-24 Scanwell Systems Instrument and method to facilitate and improve the timing alignment of a pet scanner
US7129495B2 (en) * 2004-11-15 2006-10-31 General Electric Company Method and apparatus for timing calibration in a PET scanner
KR100723492B1 (ko) * 2005-07-18 2007-06-04 삼성전자주식회사 디스플레이 드라이버 집적회로 장치와 필름 및 이들을포함하는 모듈
WO2012020670A1 (ja) * 2010-08-09 2012-02-16 株式会社東芝 核医学イメージング装置及び核医学イメージングシステム
US8796637B1 (en) * 2013-05-24 2014-08-05 Kabushiki Kaisha Toshiba Timing calibration for time-of-flight (TOF) PET using positron-emitting isotopes and annihilation targets
US10004472B2 (en) * 2014-10-27 2018-06-26 Koninklijke Philips N.V. Pet detector timing calibration
CN105395209B (zh) * 2015-12-01 2018-10-02 沈阳东软医疗系统有限公司 一种正电子发射断层扫描成像系统及方法
CN207012198U (zh) * 2017-01-22 2018-02-16 苏州瑞派宁科技有限公司 一种用于pet系统的时间校正装置

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5272344A (en) 1992-11-10 1993-12-21 General Electric Company Automated coincidence timing calibration for a pet scanner
US7030382B2 (en) 2002-10-31 2006-04-18 General Electric Company Crystal-based coincidence timing calibration method
US8089043B2 (en) * 2009-12-01 2012-01-03 Siemens Medical Solutions Usa, Inc. Systems and methods for calibrating time alignment for a positron emission tomography (PET) system
CN102783964A (zh) * 2012-07-02 2012-11-21 苏州瑞派宁科技有限公司 Pet成像中单事件列表式数据的同步方法及系统
US20150065869A1 (en) * 2013-09-03 2015-03-05 Prescient Imaging LLC Low noise transmission scan simultaneous with positron emission tomography
CN104434160A (zh) * 2013-09-18 2015-03-25 上海联影医疗科技有限公司 Pet扫描装置及其时间偏移校正方法
CN106233336A (zh) * 2014-04-23 2016-12-14 皇家飞利浦有限公司 Pet 随机符合校正
CN103976755A (zh) * 2014-05-16 2014-08-13 沈阳东软医疗系统有限公司 一种时间补偿方法及装置
CN104977601A (zh) * 2015-06-20 2015-10-14 明峰医疗系统股份有限公司 一种基于SiPM的PET系统的延时测算方法

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
See also references of EP3549526A4
XIAOLI LIBURR, K.CGIN-CHUNG WANGHUINI DU: "Timing calibration for time-of-flight PET using positron-emitting isotopes and annihilation targets", IEEE NUCL. SCI. SYMP. CONF. REC., 2013, pages 1 - 5, XP032601398, DOI: doi:10.1109/NSSMIC.2013.6829030

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111914393A (zh) * 2020-06-29 2020-11-10 上海联影医疗科技有限公司 死时间校正方法、装置、计算机设备和存储介质
CN111914393B (zh) * 2020-06-29 2024-05-28 上海联影医疗科技股份有限公司 死时间校正方法、装置、计算机设备和存储介质

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