X-ray Skin Erythema Dose (SED): Understanding Radiation Effects

The skin erythema dose (SED) for X-rays is the amount of X-ray radiation required to produce visible redness of the skin. It is typically defined as the dose that causes erythema in 50% of people exposed to it (ED50). The SED varies depending on the wavelength of the X-rays and the individual's sensitivity. For conventional X-rays (photons in the energy range of 10 keV to 1 MeV), the SED is approximately 1.5 to 2.0 Gy. This dose is much higher than the dose required for diagnostic X-ray examinations, which is typically around 0.1 mGy to 10 mGy.