An educational tool for demonstrating the TOF-PET technique

A detector system for positron emission tomography with time-of-flight capa bility has been built to serve as an educational tool for undergraduate stu dents. The set-up consists of 48 BaF2 scintillator crystals, each coupled t o a fast photo-multiplier tube, mounted in a circular geometry. The analogu e detector pulses are handled by fast constant fraction discriminators. A d edicated unit reduces the 48 channels to eight channels via delay-fine enco ding, and the signals are then fed to an eight channel fast time-to-digital converter. A VME processor sorts the events and sends them to a workstatio n where the coincident events are extracted. The time resolution of the det ectors together with fast VME based electronics allows for time-of-flight m easurements to improve on the signal-to-noise ratio in the, reconstructed i mages. The system can be used for different types of exercises for the stud ents, varying from the fundamentals of scintillator detectors to advanced i mage reconstruction. The set-up is described and some results are presented . (C) 2001 Elsevier Science B.V. All rights reserved.