The findings were similar -- with deaths ranging from 2 percent to 33 percent -- in the more than 15,000 who got abdominal CTs. The researchers think 23 people in the entire group would have gotten cancer due to radiation exposure.
"In the patients getting 15 or more scans, all of them had pretty significant disease, where their expected mortality was likely to occur much sooner than the chances of the radiation-induced cancer taking effect," Zondervan said. In other words: Those who were the sickest, requiring the most CT scans, would probably die before any cancer caused by the CT radiation could start hurting them.
Schultz cautioned that the numbers about the possible effects of CT scan radiation are based on assumptions. He added that the study suggests, but doesn't prove, that CT scans save lives.
"I do agree with their premise and their general conclusion that the risk of not doing CTs is greater than doing them," he said.
Still, patients should try to avoid radiation when possible, he said. "Ask whether the same information can be obtained in other way," he said. "In some cases, ultrasound might be better for, say, investigating possible appendicitis."
The findings are scheduled to be released May 1 at the annual meeting of the American Roentgen Ray Society, in Vancouver. The data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.
For more about CT scans, try the U.S. National Library of Medicine.
SOURCES: Rob Zondervan, medical student, University of New England, Middleford, Maine; Carl Schultz, M.D., professor, emergency medicine, and director, disaster medical services, University of California-Irvine School of Medicine; May
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