Even though the placenta cannot prevent ionizing radiation from passing from mother to fetus, the placenta itself appears to be radio-resistant.
Evidence supporting this assertion was presented at the Symposium on the Placenta, held in New York March 6, by Roberts Rugh, MD, associate professor of radiology at Columbia University's College of Physicians and Surgeons, New York.
This finding is somewhat unexpected, Rugh said, because of the great vascularity of the organ.
"Vascular endothelium has long been regarded as particularly radio-sensitive," he explained. "It is known that the adult neuron can tolerate up to 10,000 rads (r), but when the central nervous system shows effects at lower exposures they are often explained away as due to anoxia resulting from damaged vascular supply.
"It is also believed by some," he added, "that sensitivity is a function of vascularity, hence the special sensitivity of the liver, lymph nodes, spleen, and marrow."