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Lung Cancer Screening CT FAQ

This information was reviewed and approved by Debra S. Dyer, MD, FACR, Shawn D. Teague, MD, FNASCI, FACR (3/19/2024).

What is the purpose of a lung cancer screening CT?

Lung cancer screening CT is an exam tool for demonstrating lung nodules that may represent lung cancer. If caught early, lung cancer is more treatable. Early detection can improve your chances of living longer.


Who should get a screening CT?

If you are someone who is at high risk for lung cancer  — you currently smoke cigarettes or have a history of heavy cigarette smoking or you have quit smoking in the last 15 years  — the importance of early detection cannot be stressed enough. 

Good candidates for a screening CT are those who have smoked for a long length of time and who have smoked a lot of cigarettes. The impact of smoking is measured by determining the number of "pack years" a person has smoked. Pack years are calculated by multiplying the average number of packs of cigarettes smoked per day by the total number of years a person has smoked. Previous studies have shown those with a 20-pack year or greater history to be significant. Smokers with additional history of COPD, lung fibrosis, family history of lung cancer and exposure to radon, silica, cadmium, asbestos, arsenic, beryllium, chromium, diesel fumes or nickel are at higher risk.


What are the consequences of getting a screening CT?

A lung cancer screening CT exposes you to additional levels of radiation beyond what each of us is exposed to in daily life. However, National Jewish Health uses low dose CT technique and tools to keep the radiation dose as low as possible.

Secondly, a lung cancer screening CT may lead to follow-up imaging studies. Lung nodules may be identified that need to be monitored with a follow-up chest CT. Suspicious lung nodules may require additional testing such as PET-CT, biopsy or surgery to decide whether they are in fact cancerous. Other abnormalities outside the lungs may be identified such as vascular abnormalities or lesions in the liver. These may need to be evaluated further with ultrasound, CT or MRI or physician referral.


Is the radiation I’m exposed to during a CT scan a concern?

Everyone is exposed to natural radiation in the environment every day. Many imaging studies or tests expose a person to radiation. This exposure is higher than background natural radiation. There has been increased use of diagnostic imaging, especially CT, in the past 30 years. This has increased concern for lifetime radiation exposure with repeated CT scans. While there is no conclusive evidence that radiation from diagnostic exams causes cancer, there is concern that increased radiation exposure may lead to increased cancer risk. The Lung Cancer Screening CT scans at National Jewish Health are performed at the lowest dose possible. The benefits of Lung Cancer Screening CT are considered to outweigh the risks.

Learn about the Radiation Reduction Program at National Jewish Health.


I have a lung nodule. Is this worrisome?

Most lung nodules (more than 90%) are not cancerous. some nodules are benign (not cancerous) in appearance and need no follow-up. Other nodules have "indeterminate" features and need to be closely monitored, usually with a chest CT scan.  It is important that you complete any recommended follow-up appointments. 

The goal of Lung Cancer Screening CT is to identify lung cancer when it is small and at an early curable stage.


I have a suspicious lung nodule. What will happen next?

If a suspicious nodule is identified, you and your health care provider will need to meet and discuss your options. If you would like, you can be referred to one of the National Jewish Health pulmonary specialists. A suspicious lung nodule typically has irregular borders and demonstrates growth over time. If a nodule is highly suspicious, you may need to see an interventional pulmonologist and perhaps a thoracic surgeon to determine the next steps. Additional procedures may be required such as PET-CT, bronchoscopy  with biopsy, CT-guided lung biopsy or surgery.