Small-Animal PET Detector Module Based on Multichannel Digital Silicon Photomultipliers

Abstract

Positron Emission Tomography (PET) is a nuclear-medicine imag- ing technique used extensively in diagnosis of early stage tumors and cancers. Apart from clinical applications, PET is also employed in biomedical and pharmaceutical research. For this purpose, small- animal PET scan systems have been developed with superior per- formance metrics and cost efficiency. Small-animal PET scan systems provide higher spatial and temporal resolution. Conventionally, PET scan systems are developed using photomultiplier tubes (PMTs) which have certain intrisnsic limit on spatial and temporal resolution. The prospect of designing PET scan systems with solid-state based pho- tomultipliers is quite rewarding in terms of detector miniaturization and higher spatial and temporal resolution. The thesis project presented hereafter discusses the design im- plementation of a small-animal PET scan detector module based on multichannel digital silicon photomultipliers (MD-SiPMs). It outlines the design details of the MD-SiPMs i.e., its pixel and array architec- ture, readout mechanism, on-chip time-to-digital converters (TDCs). The firmware development over field-programmable gate arrays (FP- GAs) is presented next, followed by radiation characterization using a 22Na radioactive source. Finally, a proof of concept for timing esti- mation using multiple timestamps is provided.