Coincidence measurement of 350μm pitch pixelated CdZnTe detector with LSO PET module

A coincidence detection system between 350μm pitch pixelated CZT detector and a LSO-based Inveon PET detector was built up for PET imaging application. Using different trigger mode, we studied how the triggering strategy affects the PET imaging resolution. We obtained 670μm at FWHM image resolution for coincidence events detected by CZT central pixel only. If we include coincidence events from CZT double-pixel charge sharing events (while the CZT central pixel still got the biggest signal amplitude), the PET image resolution degrades to 730μm FWHM, but the count rate increases 2.5 to 3 times. We estimated the CZT timing property in different coincidence approaches, i.e. triggered by CZT anode signal or LSO signal, based on the electron drift time measurement from one flash ADC system and the measurement of trigger time difference of LSO and CZT signals.