A new detector consisting of a monolithic array of silicon avalanche photodiodes (APDs) coupled to a bismuth germanate (BGO) scintillator array will be fabricated and tested. The prototype detector array will be evaluated for its potential to be incorporated into a positron emission tomography (PET) scanner that will have higher resolution than any commercial scanner presently available. Since APDs can be fabricated using semiconductor processes that are intrinsically less expensive and more reliable than the techniques used to build photomultiplier tubes (PMTs), detector arrays built using APDs may be the only cost-effective means of achieving the higher resolution needed to improve the detection and localization of PET. The architecture of an Application Specific Integrated Circuit (ASIC) will also be developed to process the low- noise, high-speed signals provided by the detector array. During Phase II of this project, an optimized APD array will be developed and the associated ASIC architecture will be implemented. A packaging scheme will be devised to permit the ASIC electronics to be attached directly to the APD/BGO detector module. The final product of Phase II will be a detector/electronics module suitable for incorporation into a higher resolution PET system.
