Advantages of Digitally Sampling Scintillation Pulses in Pileup Processing in PET

Abstract

A novel digital signal processing method called digital-single-event-reconstruction (DiSER) is proposed to detect pileups, and to recover the timing and the energy information of each single event from a pileup. For each digitized waveform, the DiSER method can distinguish multi-event pileups from single-event pulses by counting the leading edges in a scintillation's duration. Leading edges are identified from the derivative of the waveform. Each leading edge and its following tail are utilized to reconstruct the scintillation pulses in a pileup. Two or more reconstructed single-event pulses can be retrieved from a detected pileup. Consequently, the timing and the energy information of the single event could be derived from the reconstructed pulse. Compared to the conventional pulse processing method, the DiSER method significantly increases the counts of coincidence events in high count rate cases. The energy spectrums, coincidence timing histograms and flood maps obtained by the DiSER method and the conventional method are compared. The effect of sampling rate on the DiSER performance is investigated as well. The experimental results suggest that the DiSER method is a promising digitally sampling scintillation pulses technique for pileup processing in PET.Index Terms-Digital signal processing, pileup, positron emission tomography (PET), scintillation pulse.

Performance evaluation of the Trans-PET®BioCaliburn® SH system

“…First, it is the first commercial system that is based on a new MVT DAQ technique that provides digital waveform samples. In the future, one may employ certain novel digital processing algorithms to enhance certain aspects of the system imaging performance without requiring hardware modifications (for example, applying pile-up processing to improve the count-rate performance [17,18]). Second, the output of all BDMs are stored in a PC and then processed by software for energy qualification and coincidence filtering.…”

Performance evaluation of the Trans-PET®BioCaliburn®LH system: a large FOV small-animal PET system

“…However, based on NECR measurements obtained for the mouse-and rat-sized phantoms, we observe that the count-rate performance of the system is adequate for preclinical imaging that employs no more than ∼30 MBq (∼ 810 μCi) of activity. As demonstrated in our previous work (Wang et al 2012, Deng et al 2013, the count-rate performance of the BDM can be improved by applying novel digital algorithms to analyze pile-up events. We will consider inclusion of such algorithms in the future work.…”

Performance evaluation of a 90°-rotating dual-head small animal PET system

“…From figure 13, without any processing, the pulse pileup occurs frequently in the photon acquisition, thus is one of the major problems limiting the count rate. To address this problem, a digitalsingle-event-reconstruction (DiSER) (Wang et al 2012) method was proposed to process the pulse waveform. For each digitized waveform, the DiSER method can distinguish multi-event pileups from single-event pulses by counting the leading edges in a scintillation's duration, and recover the timing and the energy information of each single event from a multi-event pileup, thus the count rate can be further improved.…”