Radium-226 retention in placenta and whole body of rat. Preliminary studies.

The 226 Ra retention in the placenta of rat during 3 successive pregnancies (92-213 days after injection) was about 4-5 × 10 -3 % of the injected dose (ID) constituting nearly 0.009% of the whole body 226 Ra content (45-55%ID) in each pregnancy. Thus a uniform relationship was being displayed between the two contents to a reasonable extent. The implication of this observation is discussed vis-a-vis the determination of Ra body burden.