Modular Camera Design Study for Human Brain SPECT System

Single-photon emission computed tomography (SPECT) can be used with a wide variety of radioligands for drug discovery and pharmacokinetic studies of promising drugs for neurodegenerative diseases. We are developing a human brain SPECT system with a stationary array of detectors that will provide dynamic high-resolution, high-sensitivity imaging. We are assessing the benefits of incorporating cylindrically curved scintillation detectors, which - due primarily to significant reduction in depth of interaction uncertainty - have resolution advantages over planar detectors at the edges. We are studying the use of a cylindrically curved to planar fiber optic plate to transfer the scintillation light from the curved crystal and light guide to a planar surface for photodetection using conventional methods. Another design component being evaluated is a novel light-sensor configuration combining photomultiplier tubes (PMTs) and silicon photomultipliers (SiPMs). Simulation methods were used to predict performance of a variety of detector layouts. The purpose of the study was to balance the tradeoff between detector cost and performance, as the final imager will be comprised of 24 camera modules. We demonstrate that combining PMTs and SiPMs for electronic readout achieves a spatial resolution advantage at the edges while maintaining a lower cost than a full SiPM readout or a curved detector.