A Pixelated Emission Detector for RadiOisotopes (PEDRO)

The Pixelated Emission Detector for RadiOisotopes (PEDRO) is a hybrid imager designed for the measurement of single photon emission from small animals. The proof-of-principle device currently under development consists of a Compton-camera situated behind a mechanical modulator. The combination of mechanical and electronic (hybrid) collimation should provide optimal detection characteristics over a broad spectral range (30keV≤Eγ≤511keV), through a reduction in the sensitivity-resolution trade-off, inherent in conventional mechanically collimated configurations.This paper presents GEANT4 simulation results from the PEDRO geometry operated only as a Compton camera in order to gauge its advantage when used in concert with mechanical collimation—regardless of the collimation pattern. The optimization of multiple detector spacing and resolution parameters is performed utilizing the Median Distance of Closest Approach (MDCA) and has been shown to result in an optimum distance, beyond which only a loss in sensitivity occurs.