Vrije Universiteit Brussel, Belgium.
A fully 3D small PET scanner based on a novel detection principle for gamma rays is described. It uses BaF2 scintillator and photosensitive wire chambers. Extensive tests with technical prototypes have shown that such a system will have a detection efficiency for gamma rays comparable with what can be obtained with the more traditional approach, and a spatial resolution determined by the size of the crystals. The expected performances of the scanner, based on our measurements and on simulations, are given.