A branch of physics that is concerned with the study of the hazards of ionizing radiation and other aspects of atomic physics, and its harmful effects on human life. It has particular application in the protection of industrial workers in the nuclear power and nuclear fuel reprocessing industries, as well as medical workers and researchers in related fields. It considers monitoring and establishing safe and permissible levels of radiation dosage, the disposal of radioactive contaminated waste, and measures for shielding against radiation exposure. See dose.