Although determinations of radiation absorbed dose estimates for internally administered radiopharmaceuticals have been facilitated through the use of recently published S-factors, extensive data manipulation is still required in many cases. Computer programs for determination of cumulated activity from experimentally measured retention data and computer programs for determination of radiation absorbed dose using the new S-factors are described. These programs, which are available from the Biomedical Computing Technology Information Center of the Oak Ridge National Laboratory, can be used to eliminate the tedious and repetitive calculations required in internal dosimetry.