Patent attributes
High sensitivity and high spatial resolution detection modules are provided that that can be built into an array or incorporated into PET or other types of gamma ray detectors and imagers. Each detection module has a scintillation detector block, light detector and optional light guide. The detector block may be formed of a first scintillation layer material that has a fast decay constant and high light output (e.g. LYSO) and a second scintillation layer material with a slow decay constant and a lower light output (e.g. BGO) with a first layer to second layer array pitch ratio of approximately 2:3. Due to the large difference of light output and decay time of LYSO and BGO signals, three different types of events (LYSO, BGO and CLCS) can be identified with high accuracy.