The system design, engineering architecture and preliminary results of a lower-cost high-sensitivity high-resolution Positron Emission Mammography camera

A lower-cost high-sensitivity high-resolution Positron Emission Mammography (PEM) camera is developed. It consists of two detector modules with the planar detector bank of 12×20 cm². Each bank has 60 low-cost PMT-Quadrant-Sharing (PQS) blocks arranged in a 10×6 array with two types of geometries. One is the symmetric 19.36×19.36 mm² block made of 1.5×1.5×10 mm3 LYSO crystals in 12×12 array. The other is the 12×13 asymmetric elongated block made of 1.5×1.9×10 mm³ crystals. One row (10) of the elongated blocks are used along one side of the bank to reclaim the half empty PMT photocathode in the regular PQS design to reduce the dead area at the edge of the module. The bank has a high overall crystal packing fraction of 88%, which results in a very high sensitivity. Mechanical design and electronics have been developed for low-cost, compactness and stability. Each module has four Anger-HYPER decoding electronics that can handle a count-rate of 3 Mcps for singles. A simple two-module coincidence board with a hardware delay window for accidental events has been developed with an adjustable window of 6–15 ns. Some of the performance parameters have been studied by preliminary tests and simulations, including the decoding quality and energy resolution of the detectors, and the point source sensitivities, spatial resolutions and phantom images of the whole system.