Radiation risks from exposure to chest computed tomography

Since 1972, when the first clinical computed tomography (CT) scanner was installed, amazing advances in CT technology have spurned its rapid growth and increasing utilization. Although CT scans are often performed for clinically valid indications that enable proper medical decision-making, the introduction of some protocols has outpaced the scientific data supporting their appropriateness. Considering the growing volume of CT scans performed and the appurtenant risks of radiation exposure, any exposure of patients to radiation for unnecessary or undocumented indications is worrisome. In this paper, the radiation risks associated with chest CT in 3 specific scenarios are discussed: (1) lung cancer screening, for which scientific data demonstrating a reduction in lung cancer mortality is lacking; (2) CT coronary artery angiography, for which the peer reviewed scientific literature is in evolution as its clinical utility is defined and expanded; and (3) CT pulmonary angiography, which is now widely utilized as the imaging modality of choice in the diagnosis of pulmonary emboli. The risks and benefits of these studies will be reviewed in light of the population radiation burden and the appropriateness of each examination.