A radiation detector for combined detection of low-energy radiation quanta and high-energy radiation quanta has a multi-layered structure. A rear scintillator layer (5) is configured to emit a burst of scintillation photons responsive to a high-energy radiation quantum being absorbed by the rear scintillator layer (5). A rear photosensor layer (6) attached to a back side of the rear scintillator layer (5) is configured to detect scintillation photons generated in the rear scintillator layer (5). A front scintillator layer (3) arranged in front of the rear scintillator layer (5) opposite the rear photosensor layer (6) is configured to emit a burst of scintillation photons responsive to a low-energy radiation quantumbeing absorbed by the front scintillator layer (3). A front photosensor layer (2) attached to a front side of the front scintillator layer (3) opposite the rear scintillator layer (5) is configured to detect scintillation photons generated in the front scintillator layer (3). The high-energy radiation quantum is a gamma ray and the low-energy radiation quantum is an X-ray.