Computed tomography (CT) scans are known to be life-saving diagnostic and screening tools with their ability to detect cancer, blood clots, broken bones, internal bleeding and other abnormalities. But many people don't know that repeated exposure to such radiation by CT scans is associated with an increased lifetime risk of cancer—even though that probability is thought to be very small.

A new study estimates that one-third of all people who undergo a CT scan don't realize their bodies are exposed to radiation. And those who are aware underestimate the amount of exposure.

Researchers surveyed 235 patients having a non-emergency scan. When asked what they were thinking before the scan, more people were worried about being able to have their parking validated after the scan than about possible radiation effects. While the benefits of most scans outweigh their risks, there are certain things you can do to ensure that you’re not needlessly exposed to radiation if your doctor suggests a CT scan.

First, ask whether there's any safer alternative, such as an MRI. Second, keep a record of all medical imaging tests you undergo. Your doctor can then consider radiation exposure you've had in the past when deciding whether to order a CT scan.

Source: JAMA Internal Medicine, published online 12/31/12; Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50

Publication Review By: the Editorial Staff at

Published: 05 Aug 2013

Last Modified: 05 Aug 2013