Are CT Scans Sometimes Too Risky?
Study Shows Radiation Doses From CT Scans Vary Widely
WebMD News Archive
Radiation From CT Scans continued...
The dose ranges were high. For example, for a head CT scan, while the median
dose was 2, the range was 0.3 to 6. "'That is a huge range," she says.
Most dramatic, she says, was the dose and the dose range for a multiphase
abdomen and pelvic series. While the median dose was 31, the range was from 6
Then the researchers estimated the lifetime cancer risk linked to the CT
scan. They estimated that one in 270 women and one in 600 men who got a CT
coronary angiogram at age 40 would develop cancer from that scan. They also
estimated that one in 8,100 women and one in 11,080 men who had a routine head
CT scan at age 40 would develop cancer.
CT Scans and Cancer
In another report published in the Archives of Internal Medicine, a
team of researchers led by Amy Berrington de Gonzalez, DPhil, an investigator
at the National Cancer Institute, also estimated the risk of cancer
attributable to CT scans.
After looking at data from previous reports of radiation-linked cancer risk,
insurance claims and nationwide surveys, they concluded that 29,000 future
cancers could be related to the 70 million CT scans performed in the U.S. in
This includes an estimated 14,000 cases resulting from scans of the abdomen
and pelvis; 4,100 from chest scans; 4,000 from head scans; and 2,700 from CT
angiograms. One-third of these projected cancer cases would occur following
scans performed on people ages 35 to 54. Two-thirds of the cancers would be in
women, according to a news release.
The high number of cancers attributed to scans of the abdomen and pelvis is
not surprising, according to Berrington de Gonzalez, since they are so commonly
done. "One-third of the 70 million [scans] were abdominal and pelvic."
The new research will hopefully raise awareness among doctors and consumers,
says Rita Redberg, MD, professor of medicine at the University of California
San Francisco and editor of the Archives of Internal Medicine, who wrote
an editorial to accompany the reports.