The development of a low-cost large-area high-resolution breast positron emission mammography (PEM) camera

Objectives Current PEM cameras use expensive PSPMT/APD to achieve high-resolution. Our goal is to develop larger area 1.5-mm resolution PEM using regular PMT with considerably lower cost.

Methods Our PEM consists of two planar detector modules with the bank area of 12x20 cm. Each bank has 60 low-cost PMT-Quadrant-Sharing LYSO blocks arranged in 6 rows (10 blocks each) with two types of blocks: 5 rows of symmetric 12x12 blocks using 1.5x1.5x10 mm crystals; 1 row of asymmetric 12x13 elongated blocks using 1.5x1.9x10 mm crystals. Elongated blocks are used along one side of the bank to reduce the dead area at the module edge. Mechanical and electronic design is developed for low-cost, compact and stable purposes. Each module has four Anger-HYPER decoding electronics that can handle 3 Mcps single events. A simple two-module coincidence board with hardware delay window for randoms is developed with 6-15 ns adjustable window.

Results The PEM development is completed and the performance parameters are studied by tests and/or Monte Carlo simulations. The overall crystal packing fraction for detector panel is 88% and energy resolution is 14.2%. Point source sensitivity is 11.5%-6.3% when bank-to-bank distance is 50-100 mm. Best spatial resolution is measured to be ~1.2 mm. Count rate performance is calculated by simulation. Phantom images are studied by experiments and simulations.

Conclusions A new large-area low-cost PEM camera has been successfully developed. Simulations and experiments show the high-sensitivity, high-resolution, high count-rate and good image quality of the PEM system.