A PET CAMERA SIMULATOR WITH MULTISPECTRAL DATA-ACQUISITION CAPABILITIES

The Sherbrooke PET simulator was designed and built to investigate par ameters which influence the performance of a high resolution PET camer a based on avalanche Photodiode detectors. The simulator consists of a computer controlled scanning table with 32 detection channels shared between front-end cassettes and FASTBUS boards, and of a PC-based mult ichannel analyzer (MCA) used as an histogramming memory for multi-para metric data acquisition. Tomographic data am collected by scanning one of two opposite arrays of detectors and by rotating the object in a p redetermined sequence to simulate a complete ring of detectors with va rious sampling schemes. All acquisition parameters, such as detector b ias, discriminator noise thresholds, timing delays, energy and coincid ence time windows, are programmable through digital-to-analog converte rs or on-board registers. Data can be acquired in several modes: calib ration, where direct or coincident energy spectra from all detectors c an be registered simultaneously; standard, where only energy-validated coincident events are histogrammed as lines-of-response (LORs) addres ses; and multispectral, where the LOR address is encoded with the ener gy information to provide a multi-parameter histogram. Data samples ob tained in these modes are presented.