Past and present nuclear fuel workers with demonstrated or potential exposure to lung carcinogens (eg, asbestos, radiation, and/or beryllium) have been screened for early lung cancer with a low-dose (LD) mobile CT scanner at three sites in the states of Kentucky, Ohio, and Tennessee. The age the of subjects was ≥ 45 or 50 years, depending on the duration of smoking and/or occupational exposure. Those with evidence of asbestos-related disease or be sensitization were eligible at any age or with any smoking history. Indeterminate nodules on LD CT scans were rescanned using a full-dose (FD) high-resolution technique. Patients with nodules that remained indeterminate were rescanned at 3, 6, 12, and 18 months. Incidence screens were performed 18 months after the initial scan.