Front-end electronics for a 1 mm<sup>3</sup> resolution avalanche photodiode-based PET system with analog signal multiplexing

We are developing a 1 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> resolution breast-dedicated Positron Emission Tomography (PET) system with 4608 Position Sensitive Avalanche Photodiode (PSAPD) detectors. This paper focuses on three aspects of the system's front-end electronics: multiplexing of the PSAPD analog output signals, scaling the dynamic range of the PSAPD output signals using charge attenuation, and positioning of individual interaction energy depositions that are below the 511 keV photo-peak.