Safety · Radiation Biology

Radiosensitivity by Age and in Utero: The Law of Bergonié and Tribondeau

Follow radiosensitivity from the embryo to old age, then sweep through pregnancy to see which effect each gestational stage risks.

In utero: Highest. Humans are most radiosensitive before birth.

Law of Bergonié and Tribondeau: Radiosensitivity follows a cell's metabolic state. Stem cells, young tissue and cells that divide and grow quickly are the most sensitive, and mature cells are the most resistant.
Why the embryo ranks highest: Its cells divide rapidly and have not yet specialized, so the same law makes the embryo and fetus the most radiosensitive stage of life.