Radiation effect that leads to a permanent functional impairment of an individual or a population (genetic radiation damage). By definition, the term depends on how sensitive the possibility of detecting such an impairment is and thus, among other things, on the state of biological, in particular radiobiological, research. The extent of the damage depends on the total radiation dose, its fractionation and the volume of the irradiated tissue (see also cutaneous radiation syndrome). The consequences of radiation damage can include: radiodermatitis acuta, radiodermatitis chronica, cutaneous X-ray fibrosis, X-ray keratoses, X-ray ulcers, X-ray carcinoma.