The invention concerns a method for determining the depth of an interaction in a pixellated gamma radiation detector characterized in that it comprises the following steps: —detecting first photons on the detector (10)； —measuring the arrival time (Tpc) of said first photons on the detector (10) for a central pixel； —measuring the arrival time (Tpa) of the first photons in a pixel adjacent to said central pixel； —comparing the time (Tpa) with the time (Tpc) in order to estimate the depth of interaction (Z) owing to the different light propagation speeds in adjacent pixels； —integrating the radiation emitted over the whole of the emission of a crystal of the detector in order to determine the energy of the interaction； and —recording the integral of the energy emitted by this detection. The invention further concerns a pixellated gamma radiation detector for implementing the above method. The invention further concerns a method of time calibration of pixellated detectors between same and the application of said pixellated detector in PET imaging.
