Patent ID: 8344328

Claim:
A three-dimensional radiation position detector comprising: a photodetector having a plurality of photodetecting elements; and a scintillator crystal having an optical anisotropy such that an optical property in a first direction is different than in other directions, the scintillator crystal being disposed on a photodetecting surface of the photodetector such that the first direction of the scintillator crystal is not perpendicular to the direction normal to the photodetecting surface of the photodetector, wherein the scintillator crystal has a length, in the first direction, of at least three times the average pitch of the plurality of photodetecting elements, and wherein the optical anisotropy is such that at least 4% of scintillation light emitted from a region directly above and farthest from the photodetecting elements is allowed to reach the photodetecting elements, and 4% to 35% of scintillation light emitted from a region immediately above and closest to the photodetecting elements is allowed to reach the photodetecting elements.