A dose of how many Gy or more can cause skin erythema?

Skin erythema, which is the reddening of the skin caused by increased blood flow to the area, is a well-recognized effect of radiation exposure. This phenomenon typically occurs when the skin receives a sufficient dose of radiation.

Research indicates that doses starting from around 2 Gy (Gray) can lead to observable skin erythema. At this level, the radiation begins to damage the skin's cells and blood vessels, resulting in the characteristic redness. The threshold for erythema reflects the body's response to the skin's vascular changes due to radiation injury.

Lower doses, such as 0.25 Gy, 0.5 Gy, or even 1 Gy, are not typically high enough to produce erythema, as they may not cause sufficient cellular or vascular damage in the skin. Therefore, understanding the relationship between radiation dose and biological effects, including skin reactions, is crucial in radiation safety and health physics.