PEDRO: A hybrid small animal imaging system

The Pixelated Emission Detector for RadiOisotopes (PEDRO) is a hybrid emission imaging system designed for the measurement of single photon emission from small animals. The PEDRO is based on the combination of mechanical and electronic collimation (through the Compton effect). It utilizes a Compton-camera stack geometry situated behind an aperture array to modulate the incident radiation. The geometry is intended to maximize detection efficiency over a wide range of photon energies whilst maintaining the enhanced resolution of Single Photon Emission Imaging (SPEI). Geant4 simulations have been performed to allow validation of the model with experimental and theoretical data. This paper presents a preliminary validation of the simulation and an investigation into the effects of detector spacing for a multi-plane detector geometry.