Quasi-continous detector module design for high-resolution small animal PET

The purpose of the work reported here was to carry out design and development of a high-resolution volumetric PET detector module based on a generalization of our single-plane design. The design evaluated consists of an array of ten 1.2 × 7 × 50 mm LSO crystals viewed by an array of eight photomultipliers. In general this design is extendable to larger axial dimension using longer crystals and additional photomultiplier tubes. The optical boundary pattern between crystals mimics a block detector in the radial direction while the optics relates to a continuous detector in the axial direction with the crystal boundaries enhancing uniformity of response. Results of singles measurements on a test block indicate that all crystals are identified radially and singles resolution on the order of 2 mm can be achieved axially over the central 80% axially. The advantages of this design include ease of fabrication, continuous axial sampling and lower light losses than modules constructed of individual crystal elements.