Performance evaluation of a table-top Compton camera for various detector parameters

A prototype table-top Compton camera, composed of two small plane-type position-sensitive semiconductor detectors, is under development. The objective of this study was to find the optimal imaging conditions for the Compton camera in order to maximize its performance in terms of imaging resolution and imaging sensitivity. To that end, the performance of the Compton camera was simulated varying several detector parameters (i.e., the photon energy of the source, the geometrical configuration of the component detectors, and the interaction position resolution of the absorber detector), using the GEANT4 detector simulation toolkit. The Compton camera was found to show its highest performance for the photon energy of 364.5 keV (131I), but also showed a relatively high performance for 511 keV (18F) and 662 keV (137Cs). The Compton camera showed its highest performance also when the scatterer and absorber detectors were positioned in parallel, separated by 10 cm. Finally, it was found significantly beneficial to the imaging resolution to increase the interaction position resolution of the absorber detector to 0.3×0.3 cm2 in the planar direction and to 0.5 cm in the axial direction.