CN109567845B - Method for constructing random coincidence cases of PET system by case mixing method - Google Patents
Method for constructing random coincidence cases of PET system by case mixing method Download PDFInfo
- Publication number
- CN109567845B CN109567845B CN201811416449.0A CN201811416449A CN109567845B CN 109567845 B CN109567845 B CN 109567845B CN 201811416449 A CN201811416449 A CN 201811416449A CN 109567845 B CN109567845 B CN 109567845B
- Authority
- CN
- China
- Prior art keywords
- random coincidence
- cases
- case
- random
- pairs
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 30
- 238000002156 mixing Methods 0.000 title claims abstract description 11
- 108020000318 saccharopine dehydrogenase Proteins 0.000 claims abstract description 19
- 239000013078 crystal Substances 0.000 claims abstract description 11
- 230000000007 visual effect Effects 0.000 claims abstract description 5
- 239000000203 mixture Substances 0.000 claims description 3
- 102100031784 Loricrin Human genes 0.000 description 11
- 239000003814 drug Substances 0.000 description 4
- 239000000700 radioactive tracer Substances 0.000 description 3
- 238000009499 grossing Methods 0.000 description 2
- 230000004060 metabolic process Effects 0.000 description 2
- 230000002285 radioactive effect Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 238000002591 computed tomography Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 238000003745 diagnosis Methods 0.000 description 1
- 238000002059 diagnostic imaging Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 235000014113 dietary fatty acids Nutrition 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 229930195729 fatty acid Natural products 0.000 description 1
- 239000000194 fatty acid Substances 0.000 description 1
- 150000004665 fatty acids Chemical class 0.000 description 1
- 239000008103 glucose Substances 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 230000002503 metabolic effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000009206 nuclear medicine Methods 0.000 description 1
- 102000039446 nucleic acids Human genes 0.000 description 1
- 108020004707 nucleic acids Proteins 0.000 description 1
- 150000007523 nucleic acids Chemical class 0.000 description 1
- 238000002600 positron emission tomography Methods 0.000 description 1
- 102000004169 proteins and genes Human genes 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
Images
Classifications
-
- 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
- A61B6/52—Devices using data or image processing specially adapted for radiation diagnosis
- A61B6/5205—Devices using data or image processing specially adapted for radiation diagnosis involving processing of raw data to produce diagnostic data
Landscapes
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Medical Informatics (AREA)
- Radiology & Medical Imaging (AREA)
- Molecular Biology (AREA)
- Biophysics (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Optics & Photonics (AREA)
- Pathology (AREA)
- Physics & Mathematics (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- High Energy & Nuclear Physics (AREA)
- Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Nuclear Medicine (AREA)
- Measurement Of Radiation (AREA)
Abstract
The invention discloses a method for constructing a random coincidence case of a PET system by adopting a case mixing method, which is used for acquiring the random coincidence case acquired by the PET system; counting rate or count for each crystal in the case of statistical random coincidenceCounting; obtaining crystal count distribution and normalizing; selecting a pair of random coincidence cases and N pairs of other random coincidence cases; one pair of random coincidence cases or N pairs of other random coincidence cases
Photon 1 and
combining the photons 2 in pairs to form new four or 2N pairs of random coincidence cases; combining the new four or 2N pairs of random coincidence instances into four LORs or 2N pairs of LORs; judging whether the LOR meets the condition or not, and removing the LOR out of the visual field; the invention provides a method for simplifying the process and reducing the error by adopting a case mixing method to construct random coincidence cases in a PET system.
Description
Technical Field
The invention relates to the technical field of medical imaging equipment, in particular to a method for constructing a random coincidence case of a PET system by adopting a case mixing method.
Background
Positron Emission computed Tomography (Positron Emission Tomography) is a relatively advanced clinical examination imaging technology in the field of nuclear medicine. By injecting the radioactive tracer medicine into human body, the radioactive nuclide in the medicine decays to produce a pair of gamma rays, so as to obtain the distribution diagram of the radioactive medicine in human body. The radiotracer is generally selected from substances necessary for the metabolism of biological life, such as: glucose, protein, nucleic acid, fatty acid, short-life radionuclide (such as 18F, 11C, etc.) marked on the surface of the body, after the radioactive tracer drug is injected into the body, the aggregation of the substance in metabolism reflects the condition of life metabolic activity, so as to achieve the purpose of diagnosis. As the momentum of the positrons gradually decreases, they annihilate with negative electrons in the body tissue near 0, producing a pair of gamma photons at approximately 180 degrees, which are detected by the PET system detectors. If two gamma photons are detected that originate from the same positron-electron annihilation event and at least one photon scatters from the medium, such an instance is referred to as a scatter coincidence instance. If the two gamma photons detected are from different positron-positron decay events, such events are referred to as random coincidence events, the coincidence events collected by the PET system include true coincidence events, scatter coincidence events, and random coincidence events, in order to estimate the share and distribution of random coincidence cases in the coincidence cases acquired by the PET system, most PET systems acquire the random coincidence cases by adopting a delayed coincidence mode with the same time window, and thus estimate the number and distribution of the random coincidence cases in the acquired data, in the image reconstruction of the PET system, random coincidence cases are mainly deducted by means of statistical deduction, this will also pass the statistical error from the random coincidence case into the corrected image.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a method for constructing random coincidence cases in a PET system by adopting a case mixing method, which simplifies the process and reduces the error.
In order to achieve the purpose, the invention provides the following technical scheme: a method for constructing random coincidence cases of a PET system by adopting a case mixing method comprises the following steps:
(1) acquiring a random coincidence case acquired by a PET system;
(2) counting the counting rate or count of each crystal in the random coincidence case;
(3) obtaining crystal count distribution and normalizing;
(4) selecting a pair of random coincidence cases and N pairs of other random coincidence cases;
(5) combining the gamma photons 1 and 2 in the selected pair of random coincidence cases or N pairs of other random coincidence cases in pairs to form four or 2N pairs of random coincidence cases;
(6) combining the new four or 2N pairs of random coincidence instances into four LORs or 2N pairs of LORs;
(7) judging whether the LOR meets the condition or not, and removing the LOR out of the visual field;
(8) calculating the probability of generating random coincidence case of new composition according to formula
Calculation of where Ncounts2Is the count rate of gamma photons from cycle two at the corresponding crystal position;
(9) the LOR is stored in terms of weight values;
(10) the data is stored as sinogram or coincidence data.
And further determining a method multiple for generating the random coincidence case according to the value size of the N value.
In summary, in the present invention, two pairs of γ photons are extracted from any two existing random coincidence instances, and the two pairs of γ photons are freely combined, thereby generating any number of random coincidence instances, supplementing the random coincidence instances acquired at a single time, and removing the combined random coincidence instances which are not in the field of view. The statistics of the random coincidence case generated by the method is high enough, and the statistical error in the random coincidence case is reduced to a negligible degree, so that the processes of downsampling, smoothing, reverse interpolation and the like can be skipped, and the image reconstruction time is reduced.
Drawings
FIG. 1 is a flow chart of a method of the present invention for constructing random coincident instances of a PET system using a case-blending approach.
Detailed Description
An embodiment of the method of the present invention for constructing random coincident instances of a PET system using the case-mixing method is further described with reference to fig. 1.
A method for constructing random coincidence cases of a PET system by using a case mixing method comprises the following steps: acquiring a random coincidence case acquired by a PET system; counting the counting rate or count of each crystal in the random coincidence case; obtaining crystal count distribution and normalizing; selecting a pair of random coincidence cases and N pairs of other random coincidence cases; combining the gamma photons 1 and 2 in the selected pair of random coincidence cases or N pairs of other random coincidence cases in pairs to form four or 2N pairs of random coincidence cases; combining the new four or 2N pairs of random coincidence instances into four LORs or 2N pairs of LORs; judging whether the LOR meets the condition or not, and removing the LOR out of the visual field; calculating the probability of generating random coincidence case of new composition according to formula
Calculation of where Ncounts2Is the count rate of gamma photons from cycle two at the corresponding crystal position; the LOR is stored in terms of weight values; the data is stored as sinogram or coincidence data.
The invention extracts two pairs of gamma photons from any two random coincidence cases, and freely combines the two pairs of gamma photons to generate any more random coincidence cases, supplements the random coincidence cases acquired at a single time, removes the random coincidence cases which are not in the visual field range, saves the obtained LOR according to the weight value obtained by calculation, stores the saved data into a sinogram or a coincidence data map, has high enough statistics for generating the random coincidence cases by adopting the method of the invention, and reduces the statistical error in the random coincidence cases to a negligible degree, so that the processes of downsampling, smoothing, reverse interpolation and the like can be skipped, the correction process of the random coincidence cases is simplified, and the image reconstruction time is saved.
The value size of the N value determines the multiple of the method for generating the random coincidence case.
The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.
Claims (1)
1. A method for constructing random coincidence cases of a PET system by adopting a case mixing method is characterized by comprising the following steps:
(1) acquiring a random coincidence case acquired by a PET system;
(2) counting the counting rate or count of each crystal in the random coincidence case;
(3) obtaining crystal count distribution and normalizing;
(4) selecting a pair of random coincidence cases;
(5) combining the gamma photons 1 and 2 in the selected pair of random coincidence cases in pairs to form four new random coincidence cases;
(6) combining the new four random coincidence instances into four LORs;
(7) judging whether the LOR meets the condition or not, and removing the LOR out of the visual field;
(8) calculating the probability of generating random coincidence case of new composition according to formula
Calculation of where Ncounts2Is the count rate of gamma photons from cycle two at the corresponding crystal position;
(9) the LOR is stored in terms of weight values;
(10) the data is stored as sinogram or coincidence data.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811416449.0A CN109567845B (en) | 2018-11-26 | 2018-11-26 | Method for constructing random coincidence cases of PET system by case mixing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811416449.0A CN109567845B (en) | 2018-11-26 | 2018-11-26 | Method for constructing random coincidence cases of PET system by case mixing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109567845A CN109567845A (en) | 2019-04-05 |
| CN109567845B true CN109567845B (en) | 2022-04-22 |
Family
ID=65924461
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811416449.0A Active CN109567845B (en) | 2018-11-26 | 2018-11-26 | Method for constructing random coincidence cases of PET system by case mixing method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109567845B (en) |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5666776A (en) * | 1979-10-18 | 1981-06-05 | Ortec Inc | Tomograph |
| JP5389907B2 (en) * | 2008-05-28 | 2014-01-15 | コーニンクレッカ フィリップス エヌ ヴェ | Geometric transformations that maintain list mode format |
| TWI505105B (en) * | 2012-07-31 | 2015-10-21 | Nat Univ Tsing Hua | System for recycling triple event data in pet and method thereof |
| CN104036137B (en) * | 2014-06-11 | 2017-03-08 | 沈阳东软医疗系统有限公司 | A kind of method and device removing random coincidence event |
| CN104331596B (en) * | 2014-09-25 | 2017-08-25 | 沈阳东软医疗系统有限公司 | A kind of hardware based multi inclusiveness event screening technique and device |
| CN108615250B (en) * | 2018-05-31 | 2022-04-26 | 上海联影医疗科技股份有限公司 | Image reconstruction method, device, system and computer readable storage medium |
-
2018
- 2018-11-26 CN CN201811416449.0A patent/CN109567845B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN109567845A (en) | 2019-04-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Tarantola et al. | PET instrumentation and reconstruction algorithms in whole-body applications | |
| CN106108934B (en) | System and method for simultaneously emitting medicine by multiple gamma photons and conforming to nuclear medicine imaging time | |
| CN109009199B (en) | System and method for image data processing in positron emission tomography | |
| US9953442B2 (en) | Image construction with multiple clustering realizations | |
| US20180203141A1 (en) | Correcting count loss in pet system | |
| CN113226183A (en) | Determination of metabolic rate from static PET scan | |
| King et al. | Introduction to the physics of molecular imaging with radioactive tracers in small animals | |
| US10222490B2 (en) | PET scanner with emission and transmission structures in a checkerboard configuration | |
| JP2021512335A (en) | Correction method for improving quantification accuracy in list mode reconstruction | |
| Cao et al. | List-mode maximum-likelihood reconstruction for the ClearPEM system | |
| Nuyts | Nuclear medicine technology and techniques | |
| CN109567845B (en) | Method for constructing random coincidence cases of PET system by case mixing method | |
| Turkington | PET imaging basics | |
| TWI430777B (en) | Dual photons emission computed tomography system and method thereof | |
| KR20200086814A (en) | image reconstruction method to reconstruct the image by correcting the response depth information included in the observed data using the flight time information of the positron emission tomography | |
| US20220265237A1 (en) | Live Display f PET Image Data | |
| Von Schulthess | Molecular Anatomic Imaging: PET/CT, PET/MR and SPECT CT | |
| US11622737B2 (en) | Radiolabeled cell tracking and imaging | |
| US20240193828A1 (en) | Systems and methods of list-mode image reconstruction in positron emission tomography (pet) systems | |
| Azhari et al. | Nuclear Medicine: Planar and SPECT Imaging | |
| Lougovski | High Resolution Fully 3D List-mode PET Reconstruction with Integrated Event-based Motion Compensation | |
| Hademenos et al. | An improved method for simultaneous dual isotope Tc-99m/Tl-201 emission scintigraphy | |
| Diale | Influence of acquisition time and smoothing parameters on Ga-68 wholebody PET/CT image quality | |
| Moalosi | The value of different reconstruction algorithms for quantification of FDG PET brain imaging | |
| Oliveira | Influence of the time-of-flight and the acquisition time on image quality in positron emission tomography/computed tomography scanners |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |