Chest CT scans use radiation. The amount of radiation will vary based on the type of CT scan. On average, though, the amount of radiation will not exceed the amount you're naturally exposed to over 3 years. The radiation from the test is gone from the body within a few days.
Children are more sensitive to radiation because they're smaller than adults and still growing.
Exposure to radiation is associated with a risk of cancer. However, it's not known whether the amount of radiation from a chest CT scan increases your risk of cancer.
You and your doctor will decide whether the benefits of the CT scan outweigh any possible risks. Your doctor also will try to avoid ordering repeated CT scans over a short period.
The contrast dye used in some chest CT scans can cause an allergic reaction, such as hives or trouble breathing. The risk of this happening is slight. If you have an allergic reaction, your doctor can give you medicine to relieve it.
The most common contrast dye used in CT scans contains iodine. Tell your doctor if you're allergic to iodine.
The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.