Specification of gamma-ray brachytherapy sources

The National Council of Radiation Protection of America recently published a report (NCRP, 1974) on the specification of γ-ray brachytherapy sources, which includes (Appendix A) a table of data for selected nuclides. The table contains new calculated values of the γ-ray constants and exposure rate constants and these are listed in Table I, together with other published values of these data. Table I shows that, while there are differences between the published values, for most of the nuclides the variations are no greater than a few per cent.