A radiation detector module including a scintillator element configured to generate optical signals in response to incident radiation. A photodetector is coupled to at least a first surface of the scintillator element, the photodetector configured to convert the optical signals into output characterizing the radiation. An acoustic array is coupled to at least a second surface of the scintillator element, the acoustic array configured to convert acoustic signals generated in the scintillator element into output characterizing acoustic energy deposited therein.