Radiation detection assemblies and related methods, including methods of making radiation detection assemblies and devices, as well as methods of performing radiation detection. A radiation detection assembly includes a radiation detector comprising a scintillator layer and an optically transparent substrate, the detector having a first side and a second side, a first imaging photodetector optically coupled to the first side of the detector, and a second imaging photodetector optically coupled to the second side of the detector, wherein at least one of the photodetectors is a position-sensitive imaging photodetector.