CT scan radiation exposure may be more than you think

Originally posted in Insidermedicine

The amount of radiation exposure associated with computed tomography (CT) scans as well as the increased risk of cancer associated with this exposure have been estimated in two studies published in the Archives of Internal Medicine.

Here is some information about CT, or CAT, scanning:

• It is a method of examining the body without physically entering it that is used for diagnosing medical conditions

• It employs multiple X-rays that are then analyzed by computer to produce an image of the inside of the body

• Every CT scan involves exposing the patient to a small amount of radiation

Researchers from the University of California at San Francisco studied the average dose of radiation delivered to over 1,000 patients who underwent 11 of the most common types of diagnostic CT scans. They found that the amount of radiation delivered by each scan varied widely. Even when looking at the same type of scan on the same part of the body, one person’s radiation exposure could be as much as 13 times higher than another’s. The risk of developing cancer following one of these scans varied dramatically depending on how much radiation patients received as well as their age and sex.

In a second study, researchers from the National Cancer Institute in Bethesda developed a risk model to estimate how many future cancers the CT scans given to patients in 2007 would likely cause. According to their analysis, CT scans given in 2007 would cause about 29,000 cancers at some point in the future. Those most likely to cause cancer were ones of the abdomen, pelvis, chest, and head as well as those delivered to patients aged 35 to 54.

We spoke with Dr. Rebecca Smith-Bindman, MD, Department of Radiology, University of California, San Francisco one of the principal investigators, who offered some further insight.

Today’s research demonstrates that radiation exposure associated with CT scanning is higher than expected and highlights the need to develop methods of limiting this exposure.