This course is designed to establish a basic knowledge of atomic structure and terminology and provide an overview of the principles of radiation protection and interaction with living systems. Also presented are the nature and characteristics of radiation (i.e., its effects on molecules, cells, tissues and the body as a whole, X-ray production and the fundamentals of photon interactions with matter). Radiation health and safety requirements and the responsibilities of the radiation therapist for patients, personnel and the public are also incorporated. Factors affecting biological response are presented, including acute and chronic effects of radiation, survival curves, total body exposure responses, and the goals of radiation therapy.