Published in the Archives of Internal Medicine, the study drew data from the National Cancer Institute, which compared the amount of CT scan radiation exposure to the number of people stricken with cancer. They found that the scans kill nearly 15,000 people a year and create cancerous cells in twice as many patients.
This risk lessens with age as one's immune system improves, with an average of one in 1,000 individuals affected by CT scans at the age of 30.
A second study produced by the University of California at San Francisco suggests that the risks may actually be greater than that. Researchers found modern CT scans to produce between four and 13 times as much radiation as older models used in previous estimates.
These studies come on the heels of a recent study published in the Annals of Medicine, which found that CT screening for lung cancer produced a significant number of false positives.