Preliminary biodistribution studies with a hybrid positron scanner.

The hybrid positron scanner is a scanning device for imaging with short-lived positron-emitting radioisotopes. It is especially suitable for total body scanning studies. The scanner consists of two moveable parallel detectors, which are NaI(Tl)-crystals 40 cm long and 5 cm in diameter with a photomultiplier at each end. One detector is above and the other below the patient. The coordinate in the direction perpendicular to the crystal axis is determined from mechanical movement of the detectors. The coordinate along the crystal axis is determined from the signals of the photomultipliers. The specifications of the hybrid positron scanner are presented. Biodistribution studies in rabbits on the accumulation of 18F in the skeleton and on the 13NH3 distribution in various organs are described. The regional pharmacokinetics of 11C-ethanol in man after peroral administration of the tracer is presented.