A modular low dead-time coincidence system for high-resolution PET cameras

A high-resolution oncologic transformable positron emission tomography (HOTPET) is currently under development. The detector ring of the camera consists of 12 detector modules. Because the high-yield-pile-up-event-recovery (HYPER) front-end electronics are applied in this new-generation PET camera, a low-dead-time coincidence circuitry is needed to take advantage of the improved efficiency from this technology. The coincidence matching of events coming from different detector modules is performed by an AND-logic on the arriving edges of the module output timing pulses. A flexible modular architecture has been adopted to facilitate the use of the coincidence circuitry for different detector module configurations in addition to different electronic and mechanical implementations. The application of backplane/plug-in architecture and programmable devices (EPLD/FPGA) along with a digital signal processor (DSP) provide reprogrammable flexibility and expandability, allowing scans ranging from animal and breast PET to whole-body PET. There are 42 possible combinations of module pairs derived from the maximum 12 detector modules in coincidence with seven opposite modules.