Advantages of digitally sampling scintillation pulses in pileup processing in PET

Higher count rate detectors are needed for high sensitivity positron emission tomography (PET) scanners. However, the maximum count rate of the detectors is limited due to the large pileup quantity in the high count rate situation, in which pileups are rejected conventionally. In this paper, we investigate the development of a method for digitally sampling scintillation pulses for PET. We focus on employing the digital signal processing (DSP) technology for pileup events discrimination and processing, which can discriminate pileups and singles from multi-event pulses by the number of leading edges and then reconstruct each event pulse. With the application of this method, a pileup can be divided into two or more single pulses, therefore the timing and energy of a single event can be measured independently. The preliminary results show that the coincidence count rate can be increased obviously, and the timing resolution and energy resolution can be improved distinctively, so the results by using the DSP method are encouraging.