Simplified Procedure for Determining Amounts of Two Mutually Interfering Radioisotopes in Mixed Samples

Abstract

A method is described for determining concentrations of 2 radioisotopes, neither of which can be counted without interference from the other, in samples containing both isotopes. It can be applied to any 2 radioisotopes which can be counted under conditions where one predominates with a minimum contribution from the other, followed by a second counting where the reverse situation prevails. Known dilutions of dosing solutions of each isotope are counted. Using constants determined from these counting standards, concentrations of the 2 isotopes in unknown samples are calculated expressed as percentages of the administered doses. Calculations are rapid and can be made on an ordinary desk calculator.