Component resolution indices for scintillation camera systems

Abstract

From published overall resolution indices for three Anger camera systems, measured with three straight-bore collimators and 99mTc in air and with a water absorber present, the components due to inherent camera resolution, collimator geometry, and scatter are derived at various depths. Replacement of S-11 multiplier phototubes by bialkali phototubes improves calculated inherent Pho/Gamma III camera resolution by about 30% and by a further 33% upgrading to a high-performance model. At distances 2, 5, 8, and 10 cm from each collimator face with an intervening water absorber, mean scatter components of overall resolution indices are 6, 8, 9, and 10 mm, respectively. In typical clinical 99mm Tc imaging situations with a scattering medium present, the relative contributions of camera, collimator, and scatter to the total overall system resolution are presented.