ABSTRACT
Nonionizing radiation is composed of ultraviolet (UV), visible, infrared (IR), radio-frequency (RF) radiation, and extremely low-frequency (ELF) fields. Applications of nonionizing radiation have grown tremendously during the past 75 years. With this growth, there has been an increased understanding of the potential for overexposure to the various types of nonionizing radiation, and an awareness of the need to provide a comprehensive radiation safety program that includes nonionizing radiation. All nonionizing radiation is electromagnetic radiation. Electromagnetic radiation is the propagation, or transfer, of energy through space and matter by time-varying electric and magnetic fields. UV produces biological effects primarily by photochemical reactions. Photochemical effects follow photon absorption by a chromophore, which provides the activation energy for the chemical reaction. The target organs for laser-induced biological effects are the skin and eyes. The scientific understanding of the potential hazards of laser radiation comes from studies of laboratory animals, although some human data from accidents is available.
