Timing optimization with position information for TransPET

In positron emission tomography (PET) applications, coincidence timing resolution is crucial for rejecting random events, while the extremely high timing resolution can be used for time-of-flight (TOF) reconstruction. The timing resolution of PET system is determined by many factors, including the scintillator crystal, the photomultiplier (PMT) and the data acquisition system. Many efforts have been focused on these three aspects to improve the timing resolution. However, the different average arrival times of events (referred to below as timing shift) in different positions of the detector are not thoroughly studied yet. In this work, the timing shift in different positions are measured, their influence on the timing resolution of an real world PET system is investigated, and a calibration method for improving the timing resolution with timing shifts is proposed. The primary results show that the differences among timing shifts in the actual PET system worsen the timing resolution, and our method can calibrate the timing shift and improve the timing resolution.