AN IMPROVED MULTICRYSTAL 2-D BGO DETECTOR FOR PET

We evaluate and compare two new 2-D array detectors for PET. Both consist of an 8 x 8 array of small BGO crystals coupled to a 2 x 2 array of photomultiplier tubes. The depth of the crystals is 3 cm in one detector and 2 cm in the other. The 2 cm detector is obviously superior in terms of material costs, but is also superior in energy resolution per crystal, and in its ability to clearly identify the crystal containing the primary interaction. We present a flexible and robust algorithm for crystal identification in such array detectors. The prospect of obtaining still better spatial resolution from such block detectors, with increased numbers of crystals, is discussed.