Investigation of Analog and Digital Signal Processing Chains for a Prototype TOF-PET System with 100 ps Coincidence Time Resolution

To achieve < 100 ps Coincidence Time Resolution (CTR) and a > 2 - fold improvement in reconstructed image Signal to Noise Ratio (SNR) compared to state-of-the-art TOF-PET scanners, we have evaluated CTR performance of three different mixed-signal front-end electronic configurations. The proposed TOF-PET detector elements are based on two 3×3×10 mm3 “LGSO” crystal segments for a 20 mm effective length and side-coupled to arrays of 3×3 mm2 SiPMs. The front-end readouts were based on: a) high speed RF amplifiers; b) NINO ASIC as discriminator, and; c) combination of both RF+NINO. Coincidence data were experimentally acquired using the 10 mm length crystals, a low jitter FPGA-based TDC, several SiPM bias voltages, and NINO thresholds, achieving CTR value of 103.3 ± 1.5 ps FWHM using configuration (c). This value is much improved compared to the results achieved using configurations (a) and (b).