[Collimators for whole body counter enabling localization]

For the four 6 inches times 4 inches NaJ/Tl-crystals of a whole-body-counter several collimators were developed to perform not only counting but also localization. In respect of their good response, a 19-hole-collimator and several slit-collimators were designed. The geometrical dimensions were chosen in such a way that in a profile-scan one can distinguish between the right and the left side of the body. The physical characteristics, such as plane-source-response, spatial resolution, especially at high gamma-ray-energies, were obtained by analysing line-source-functions [4]. The results show that the advantages of using larger crystals are an increase of focal distance, higher sensitivity and adaptibility to high-energy-gamma-ray emitters. In consequence it is possible to decrease body burden of the patients and to use radionuclides normally not applicated in clinical routine scintigraphy.