Air kerma rate constants for radionuclides
Conversion to SI units requires that the exposure rate constant which was usually quoted in R·h-1·mCi-1·cm2 be replaced by the air kerma rate constant with units m2·Gy·Bq-1·s-1. The conversion factor is derived and air kerma rate constants for 30 radionuclides used in nuclear medicine and brachytherapy are listed. A table for calculation of air kerma rates for other radionuclides is also given. To calculate absorbed dose to tissue, the air kerma rate has to be multiplied by approximately 1.1. A dose equivalent rate constant is thus listed which allows direct calculation of dose equivalent rate to soft tissue without resorting to exposure rate constants tabulated in the special units R·m2·mCi-1·h-1 which should no longer be used.