Data acquisition system design for a 1 mm{sup}3 resolution PSAPD-based PET system

摘要

We are developing an application specific, high resolution 1 mm{sup}3 3-D PET system that comprises two detector panels that are 16 cm × 9.1 cm × 2 cm in dimension with arrays of sandwiched position sensitive avalanche photodiode (PSAPD) detectors. The system will comprise 2240 PSAPD devices per panel with approximately 11,200 channels per detector head. A data acquisition architecture is being designed around dedicated readout ASICs. The readout ASIC, the RENA-3, was developed by NOVA R&D for low noise charge sensitive readout of solid state detectors, with shaping, triggering, and timestamp generation circuitry. Using the RENA-3 evaluation system, two PSAPD devices operated in coincidence achieved a 17.2% global energy resolution, 1 mm{sup}2 spatial resolution, and 11 ns (15.5 ns paired) FWHM coincidence time resolution. A monte-carlo simulation of a PET mammography configuration was used to generate realistic count rates. The realistic count rates were then run through an event based simulation model of the PET mammography system and data acquisition to determine the count rate performance of the architecture. The data acquisition we propose with the RENA-3 ASIC readout should be able to handle a 5 mCi imaged whole body dose in a 160 cm tall woman recoding 75% of the events with a 100 keV low energy threshold.