Radiation dose and risks to fetus from nuclear medicine procedures.

This article discusses issues regarding administration of radiopharmaceuticals to pregnant women. Standardized dose estimates and possible biological effects on the unborn child are presented. Current and future mathematical models (phantoms) are discussed. Standardized dose estimates for pregnant women at several stages of gestation based on the current generation of phantoms are given. Issues related to administration of radioiodines, particularly 131I-NaI, are presented. Iodine concentrates in the fetal thyroid and therefore can give very high doses, even resulting in complete destruction of the fetal thyroid. Strategies for preventing unwanted administrations of radiopharmaceuticals to these patients, and for strategies for mitigating radiation doses, should an unwanted administration occur, are discussed.