NEW APPROACHES IN MEDICAL IMAGING USING PLASTIC SCINTILLATING DETECTORS

A small animal imaging camera was built in our laboratory, using fast plastic scintillating detectors (tau = 2-4 ns) and position sensitive photomultipliers (Hamamatsu) digitized using flash ADCs. Pinhole colli mators were used for I-125 imaging to achieve submillimeter resolution with scintillating plates of 28 mm radius and 1.5 mm thickness. A hig h resolution PET module was constructed with arrays of 1.0 mm diameter plastic scintillating fibers. The feasibility of high resolution imag ing was demonstrated by the study of brain blood flow in a rat using I -125 IMP in single photon detection mode and with Cu-64 PTSM by using PET mode. Construction of single photon and positron emission tomograp hic imaging systems for small animals and subsequently for human imagi ng is in progress.