Multiple layer positron emission tomography camera

A positron emission tomography camera comprising,

• a patient area,
• a plurality of fixed circular detector rings positioned side by side around the patient area to detect radiation from opposite sides of a patient in the patient area,
• each ring containing a plurality of scintillation detectors directed towards the patient area for defining a plane slice through the patient area by the detectors in each ring, said detectors on opposite sides of the patient detecting two oppositely directed gamma rays,
• each ring including multiple layers of scintillation detectors, the detectors in one of the layers being offset relative to the detectors in the other layers in a ring for increasing the sampling of detected radiation,
• the depth of each ring being approximately equal to the depth of conventional mono-layered detectors and the depths of each layer being approximately equal, and
• means for converting detected radiation into electrical pulses, said means positioned adjacent each ring but offset from the plane of each ring, said means directed perpendicularly to the plane of the adjacent ring.