Repeated CT scans in patients with no pulmonary nodules

If a patient enters a screening program and the first computed tomography (CT) is negative, how often are CT scans usually repeated in those with no pulmonary nodules? Is it necessary to repeat the CT scan if the first screening was negative?

Julian Dobranowski: During the course of the screening in the first 3 years, you would expect probably between 30% and 40% of the scans to be positive that we will identify. The CT scan is extremely sensitive for picking up abnormalities. The problem is with specificity. If we had pathologically balanced CT scanners, it would be a lot easier too. We identify abnormalities; however, we cannot clearly define what those abnormalities are without either taking a specimen or by following those patients temporarily and seeing what the growth rate is.