A Depth-of-Interaction encoding method for SPECT monolithic scintillation detectors

The Depth of Interaction (DoI) discrimination of gamma-photons within scintillation crystals allows to improve imaging performance in PET scanners as well as in SPECT devices equipped with non-parallel collimators (e. g. pinhole ones). In previous works, the authors exper- imentally proved the efficiency of a DoI-encoding technique in case of a 20mm-thick monolithic crystal PET module. For the thinner crystals commonly used in SPECT, DoI determination still remains a challenging goal. To this aim, in this work the authors have experimentally evaluated the DoI-encoding method on a 6mm-thick monolithic LaBr3:Ce crystal. The results prove the effi- ciency and reliability of the proposed method, ensuring a good discrimination between scintillation events occurring at top and at bottom of the crystal.