Radiation absorbed dose estimates to the embryo from some nuclear medicine procedures.

Using the specific absorbed fractions reported by Smith and Warner, the radiation doses absorbed by the embryo in early pregnancy were calculated for various radiopharmaceuticals used in the diagnostic procedures of nuclear medicine. Radiopharmaceuticals are considered which are excreted predominantly through urine and cause the doses to the embryo to be 40%--90% higher than gonad doses. Also discussed are large differences of doses reported by various authors to the embryo by 99mTc-pertechnetate.