Device and method for reducing time walks in PET (positron emission tomography) system
A comparator and high-threshold technology, applied in radiological diagnostic instruments, medical science, diagnosis, etc., can solve problems such as difficult processing, noise triggering, and large noise, and achieve the effect of improving time resolution and reducing false triggering
Pending Publication Date: 2022-05-06
JIANGSU SINOGRAM MEDICAL TECH CO LTD
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Problems solved by technology
In order to reduce the impact of time walk, the general practice is to set the threshold of the comparator very low, but if the setting is low, it will be triggered by noise, which will make subsequent processing difficult, so the threshold setting will be higher than the noise
However, in practical applications, especially SiPM detectors, the noise is relatively large, such as the noise caused by dark current. In order to reduce the false triggering of the noise band, the threshold is set relatively high, which will bring a relatively large time walk
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Embodiment 1
[0047] like Figure 2 to Figure 5 As shown, the present embodiment provides a device for reducing time walk (time walk) in a PET system, which includes:
[0048] High-threshold DAC, low-threshold DAC, high-threshold comparator, low-threshold comparator, delay circuit, logic AND gate and TDC (Timer Digital Converter, time-to-digital converter);
[0049] The output terminal of the high threshold DAC is connected to the first input terminal of the high threshold comparator; the high threshold DAC (digital-to-analog converter) is used to output the DAC of the high threshold comparison voltage value;
[0050] The output terminal of the low threshold DAC is connected to the first input terminal of the low threshold comparator, and the low threshold DAC is used to output the DAC of the high threshold comparison voltage value;
[0051] The detector output terminal is connected to the second input terminal of the high threshold comparator and the second input terminal of the low thres...
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The invention relates to a device and a method for reducing time walks in a PET (positron emission tomography) system. The device comprises a high-threshold DAC (digital-to-analog converter), a low-threshold DAC, a high-threshold comparator, a low-threshold comparator, a delay circuit, a logic AND gate and a TDC (time-to-digital converter), the output end of the high-threshold DAC is connected with the first input end of the high-threshold comparator; the output end of the low-threshold DAC is connected with the first input end of the low-threshold comparator. The output end of the detector is connected with the second input end of the high-threshold comparator and the second input end of the low-threshold comparator. The output end of the high-threshold comparator is connected with the first input end of the logic AND gate; the output end of the low-threshold comparator is connected with the second input end of the logic AND gate through the delay circuit; and the output end of the logic AND gate outputs a time pulse signal to the TDC. The device provided by the invention adopts the high-low double-threshold comparator, so that the false triggering of noise can be effectively reduced, and the time walk is reduced, thereby improving the time resolution of the PET system.
Description
technical field [0001] The invention relates to a detection technology of a PET detection system, in particular to a device and method for reducing time walk in a PET system. Background technique [0002] PET (Positron Emission Tomography), Chinese for Positron Emission Tomography, is a technology developed in nuclear medicine. During PET examination, the patient is injected with radiopharmaceuticals. Currently, the commonly used radiopharmaceuticals are positron 18F-labeled deoxyglucose (ie 18F-FDG). Radiopharmaceuticals are distributed throughout the body as they are metabolized. Radionuclides will produce β+ decay, release positrons, and collide with negatively charged free electrons in human tissues to annihilate after moving for a short distance in the human body, releasing a pair of gamma photons with opposite directions and energy of 511Kev. This pair of gamma photons is captured by a detector composed of scintillation crystals. When the scintillation crystals are h...
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IPC IPC(8): A61B6/03
CPCA61B6/037A61B6/4208
Inventor 田利波
Owner JIANGSU SINOGRAM MEDICAL TECH CO LTD