Lung cancer screening involves testing for lung cancer when no symptoms or disease history exist in an effort to increase early diagnosis, where treatments are more effective. The US Preventive Services Task Force recommends yearly lung cancer screening for individuals aged 50 - 80 who have a history of smoking 20 or more packs of cigarettes/year and currently smoke or quit smoking in the past 15 years. Screening is done via a non-invasive low-dose CT scan (LDCT) which uses a low dose of radiation to X-ray image the lungs.