1917. "Radiation burn to the hand Note the necrotic dermatitis present in this burn. This signifies either an extremely high one-time dose, or continued exposure to a moderate dose of gamma radiation. Even with a one-time exposure to the radiation, necrosis often does not set in until 2-3 weeks after the initial burn develops." This is why the dental hygienist runs out of the room so fast after she puts the lead apron on you.
