Patent ID: 6858849

Claim:
A PET apparatus comprising: a detecting section which includes a plurality of cylindrical detectors each formed by one- or two-dimensionally arraying a plurality of photon detection elements, each of which detects a photon flying from a measurement space including a central axis, on a cylinder surrounding the central axis, the plurality of cylindrical detectors being arrayed in a direction parallel to the central axis; a plurality of slice collimators which are alternately arranged with said cylindrical detectors in a direction parallel to the central axis, each of said slice collimators extending from a position between the measurement space and said detecting section to a rear portion of a corresponding one of the cylindrical detectors through a space between two adjacent cylindrical detectors of the plurality of cylindrical detectors and passing only a photon, of photons flying from the measurement space, which is substantially parallel to a predetermined plane perpendicular to the central axis toward said detecting section; a coincidence counting information accumulating section which accumulates coincidence counting information of a photon pair detected by one pair of photon detection elements included in said detecting section; and an image reconstructing section which reconstructs an image representing a spatial distribution of occurrence frequencies of photon pairs in the measurement space on the basis of the coincidence counting information accumulated by said coincidence counting information accumulating section.