Advances in imaging technology have afforded physicians an incredibly detailed view of the human body. Conditions that used to require “exploratory surgery,” in which surgeons operated to get a closer look at a patient’s organs and tissues have now been replaced by superior imaging technology, such as a 160-slice computed tomography (CT) scan that offer high-resolution, 3D images of soft tissue.
These new imaging tools have led to an increase in their usage. Between 1996 and 2010, the number of CT scans tripled, according to one study. Like many imaging tools, CT scanners expose patients to ionizing radiation that has been associated with an increased risk of developing cancer over time, especially when children have multiple CT scans.
“The amount of radiation a patient is exposed to in a CT scan varies, depending upon the test,” says Dr. David Foosaner, a radiologist at Advocate Condell Medical Center in Libertyville, Ill. “The cumulative effect of multiple CT scans can have an impact on patients over their lifetime—obviously, the more scans you have, the greater your risk. But we do have dose-reduction software with our CT scanners, which limit the amount of radiation for each patient, depending upon their size and weight, so that they receive the lowest dose possible.”
According to the American Cancer Society, “A lower GI series using standard x-rays exposes a person to about 8 mSv (millisieverts). A CT scan of the abdomen (belly) and pelvis exposes a person to about 10 mSv, this goes up to 20 mSv if the test is done with and without contrast. A CT colonography exposes you to about 10 mSv of radiation.” By comparison, the average American is exposed to 3 mSv of radiation from natural sources per year.
Most physicians agree that these tests are important when the risks of not having them done outweigh the risks of potential radiation exposure, and the tests should be ordered judiciously.
“I don't advise a head CT for headaches or migraines, unless the neurologic exam is abnormal,” says Dr. Adam Rubinstein, an internal medicine physician at Advocate Condell.
Dr. Foosaner suggests that if patients are concerned in advance of having a CT scan, “You should go to a facility that is equipped with dose reduction software to make sure you’re getting the lowest possible dose. But generally one CT scan would not likely present a danger to you.”