A PET CAMERA SIMULATOR WITH MULTISPECTRAL DATA-ACQUISITION CAPABILITIES

The Sherbrooke PET simulator was designed and built to investigate parameters which influence the performance of a high resolution PET camera 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 multichannel analyzer (MCA) used as an histogramming memory for multi-parametric data acquisition. Tomographic data am collected by scanning one of two opposite arrays of detectors and by rotating the object in a predetermined sequence to simulate a complete ring of detectors with various sampling schemes. All acquisition parameters, such as detector bias, discriminator noise thresholds, timing delays, energy and coincidence time windows, are programmable through digital-to-analog converters or on-board registers. Data can be acquired in several modes: calibration, where direct or coincident energy spectra from all detectors can be registered simultaneously; standard, where only energy-validated coincident events are histogrammed as lines-of-response (LORs) addresses; and multispectral, where the LOR address is encoded with the energy information to provide a multi-parameter histogram. Data samples obtained in these modes are presented.