Radiation Hazards to the Embryo and Fetus

Abstract

Determination of the critical periods for the occurrence of abnormalities in the development of mouse embryos irradiated with X-rays in utero were undertaken. It was found that the majority of such abnormalities occur at a time in this animal species, which corresponds to the 2nd to 6th week of gestation in man. Doses high enough to produce abnormalities did not necessarily lead to abortion. Doses as small as 25 r were found to be effective if applied during the critical developmental period. Implications of these findings for the practice of diagnostic and therapeutic radiology are discussed.