LaBr3:Ce scintillation gamma camera prototype for X and gamma ray imaging

LaBr3:Ce has been showing very promising characteristics as gamma ray imager and spectrometer. In particular its excellent energy resolution values (6% at 140 keV and ∼3% FWHM at 662 keV), obtained when coupled to a PMT, make it the major competitor of semiconductor detectors working at room temperature. In order to improve its imaging performances, the LaBr3:Ce can easily work as continuous detector allowing sub-millimeter spatial resolution values at 140 keV photon energy when coupled to a Position Sensitive PMT. Further interesting characteristics like a short scintillation decay time (16 ns), a very high light yield (63 000 photons/MeV) and a low afterglow are attracting the scientific community for the potential improvement of a wide range of applications in medicine like PET, SPECT and CT instrumentation. In this paper, we present some preliminary imaging results obtained by coupling H8500 Hamamatsu Flat Panel PMT to two LaBr3:Ce crystals with 50×50 mm2 area, 5 and 10 mm thickness respectively. With the aim to propose a single detector able to combine functional information, for example from Single Photon Emission technique, with the morphological ones from X-ray imaging the spatial resolution results obtained in the energy range between 30 and 302 keV are analyzed and discussed. We obtained very interesting spatial resolution results for gamma ray energy value greater than 60 keV (better than 1 mm, intrinsic value), while in the energy range proper to X-ray applications, like RX-Mammography (about 30 keV), the spatial resolution values resulted about 2 mm.