In 2002, the National Cancer Institute (NCI) launched the landmark National Lung Screening Trial (NLST) to determine whether spiral computed tomography was better than single-view chest x-ray in reducing deaths among current and former heavy smokers.

The rate of adherence to screening was more than 90%. The rate of positive screening tests was 24.2% with low-dose CT and 6.9% with radiography over all three rounds. A total of 96.4% of the positive screening results in the low-dose CT group and 94.5% in the radiography group were false positive results. The study concluded that screening with the use of low-dose CT reduced mortality from lung cancer.