Radiation Tolerance of the Skin

The skin has a long history of detailed clinical observations on the damaging effects inflicted by ionizing radiation.Recent knowledge of the cellular dynamics of the skin under normal conditions and in response to injury in addition to more precise methods of measuring radiation effects in cells and tissues permit new interpretations of many observed reactions.These findings may indicate approaches to the reduction of radiation injury in this and other normal structures in order to improve the ability of radiation to selectively destroy malignant disease. Review of normal skin structure and cell kineticsCellular organization.The skin is the largest organ of the body and functions as a protective and adaptive integument to the environment (65).It consists of the epidermis, dermis or corium, and subcutis.The outer layer or epidermis has a thickness ranging from 0.1 to about 0.6 mm.The four layers of this epidermis derive from randomly dividing basal cells in the germinal layer.These cells differentiate progressively as they move through the prickle cell and granular cell layers and they eventually become part of the stratum corneum (Fig. 1).The dermis serves as the base of nourishment for the epidermis.It can vary in thickness