Small Animal PET Timing Information Acquisition Module Design And Timing Calibration Research

Positron emission tomography (PET) is a non-invasive functional imaging technology.By detecting the distribution of radioactive tracer uptake in vivo, PET is able to evaluate themetabolic activity, the biochemical reaction, the biological active and the perfusion of atissue dynamically and quantitatively. As a highly-sophisticated technology used in currentnuclear diagnostic and research, PET plays a significant role in the clinical diagnosis ofoncology, cardiovascular and nervous system, and also in the researches of pathology,pharmacology and medicine development of related conditions. Compared with theconventional PET system, digital PET data acquisition system (DAQ) can effectively solvethe issues arise form environment interference and calibration difficult. Therefore, digitalDAQ become a reach hotpot due to the wide use of digital signal processing technology.In this work, we make full use of the pulse characterization and digital signalprocessing algorithm, and implement timing acquisition module in the DAQ system, whichis developed at Huazhong University of Science and Technology. By using the multi voltagethreshold method, we obtain an excellent timing performance that can fulfill the expectedrequirement.This thesis investigates a timing calibration method based on the timing resolutioncontribution matrix (TRCM), to solve the misalignment problem arising from the timingdifference between each detecting channel in the PET system. This method firstly obtains theratio between coincidence events in each LOR and the total coincidence events. Then, thechannel having significantly contribution to the timing resolution is employed to performtiming calibration. This method can effectively reduce the calibration complexity formulti-channel PET system and achieve rapid timing calibration, with significantly improvingthe timing resolution as well.This thesis proposes a local peak relocation based algorithm to implement crystalidentification for LOR-level timing calibration. This method can be used effectively inonline lookup table construction, and lays the foundation for a variety of complex correction of the PET system.