A novel parallel hole collimator for high resolution SPET imaging with a compact LaBr3 gamma camera

In this work we propose an analysis of a novel Low Energy (LE) parallel hole collimator for high resolution single photon emission tomography (SPET) applications. This prototype, realized jointly with Nuclear Fields, is a lead parallel hole collimator with 1.0 mm hexagonal hole, 18 mm length, 0.2 mm septa and 10x10 cm² of useful detection area. It has been planned to match the high spatial resolution performances of a compact gamma camera based on LaBr3:Ce continuous scintillation crystal. The imaging performances of this prototype are compared with others two parallel collimators, for different dimensions and applications, and a tungsten pinhole collimator ones. All the collimators were tested with a compact scintillation gamma camera based on LaBr3:Ce continuous crystal and multi anode photomultipler tube (MA-PMT) Hamamatsu H8500. The high intrinsic spatial resolution of this crystal enhances the response of collimators at short source-to-collimator distance (SCD) overcoming alignment problems with the collimator pattern. From our analysis the collimator prototype seems to be complementary with the use of pinhole one and when coupled to the compact LaBr3:Ce gamma camera can allow a very attractive trade-off between spatial resolution, sensitivity and detection area for radionuclide molecular imaging applications.