Are there radiation exposure risks associated with repeat CT scans?
The radiation exposures from the screening done in the NLST will be modeled to see how exposure to three low-dose CT scans changed a person’s risk for cancer over the remainder of his or her life, but that analysis will take a while to conduct. Previous studies show that there can be an increased lifetime risk of cancer due to ionizing radiation exposure. It is important to recognize that the low-dose CT used for screening in the NLST delivers a much lower dose of radiation than a regular diagnostic CT. Additionally, the benefit of potentially finding a treatable cancer in current or former heavy smokers, ages 55 to 74, using helical CT appear to outweigh the risk from receiving a low dose of radiation. For comparison purposes, a standard low-dose helical CT scan as used in the NLST delivers a small amount of radiation to several organs in the body, primarily the lung (4 mGy, or milligray, which is a measure of absorbed radiation dose) and the breast (4 mGy) but also the red bone marro