Radiation dosimetric considerations in peripheral CT angiography

Performance of any diagnostic test requires a careful assessment of the risks and benefits of the test, and optimization of test protocols to minimize the risk to patients, staff members, and the public. The underlying principle in radiation protection is the as low as reasonably achievable (ALARA) principle. Implicit in ALARA is the assumption that any dose of radiation, however small, may confer biologic risk and thus it is prudent to minimize exposure wherever possible. While the nature of the health effects of low doses of ionizing radiation remains a subject of some controversy, two expert consensus committees, the National Council on Radiation Protection and Measurements' Scientific Committee and the National Research Council's Committee to Assess the Health Risks from Exposure to Low Levels of Ionizing Radiation, have exhaustively reviewed the currently available data and concluded that the risk is best described by a ‘linear-no-threshold’ risk model. This would therefore imply, at least in theory, that for any type of examination involving radiation, reduction in radiation dose should translate to a reduction in attributable cancer incidence and mortality.