Performance of a small animal PET scanner based on photosensitive wire chambers

A 3D small animal PET scanner, designed and built at the University of Brussels, has been operational since the beginning of 1996. The scanner has a transaxial field of view (FOV) of 110 mm and an axial FOV of 51 mm. The absolute sensitivity is around 35.000 coincidences/s/MBq for a point source at the center of the scanner and the time resolution is 29 ns FWHM. To measure the achievable spatial resolution, a thin /sup 22/Na source was scanned at various distances from the scanner axis. The resolution in a reconstructed image for a source close to the center is 3.0 mm FWHM. Finally, to assess the overall image quality, scans were made of a cylindrical phantom with holes of varying diameter.