This course will concentrate on providing the biophysical basis for radiation effects and health risks and the implications for ionizing radiation dosimetry and radiation protection. The course will cover the following topics: the physics of the interaction of radiation with matter; radiation damage at the molecular, sub-cellular and cellular level; tissue damage and health effects in humans; radiation quality; regulatory requirements and radiation protection dosimetry. The primary goals are to teach students the fundamental mechanisms of radiation interactions at the molecular and cellular levels and the various biological endpoints that can result. Current concerns and controversy concerning the effects of low-dose exposures will also be covered in this course.