title: Standardizing 125I sources and determing 125I counting efficiencies of well-type gamma counting systems.
abstract: I describe the technique for determining the absolute decay rate of any 125I source. The problems of varying counting efficiency, varying sample geometry, and extended sources are discussed. By using the calibrated 125I source, the counting efficiency of the given counting system was obtained.
mesh_terms: D005069:Evaluation Studies as Topic; D007457:Iodine Radioisotopes; D008722:Methods; D011863:Radioimmunoassay; D012588:Scintillation Counting
chemical_list: D007457:Iodine Radioisotopes