Resolution properties of triple-headed coincidence imaging

Due to the rising interest in clinical PET imaging, some manufacturers adapt two-headed gamma cameras to work in coincidence mode. Recently, the use of three heads for coincidence imaging has been suggested. The three heads can be placed in different configurations to achieve optimal sensitivity profiles. Two of these configurations are U-shape and triangular. As the average angle of incidence of the photons will differ for each configuration, it is expected that the resolution properties will be different. Resolution will be degraded by angle of incidence effects, non-colinearity of the photons, and, for axial resolution, rebinning of the list mode data to two-dimensional projections. In this paper, we investigate the influence of camera configuration, detector radius and scatter medium on transaxial and axial resolution properties. FWHM and FWTM were measured for different values of these parameter, and compared with each other.