A health expert with the American Association of Physicists in Medicine (AAPM) says that the possible hazards of CT scans, mentioned in a recent article in the New England Journal of Medicine, are overstated.
Dr. John M. Boone, chairman of AAPM's science council, says that the concerns raised in the article should not scare people away from getting medically needed CT scans because the scans play a critical role in saving thousands of lives daily.
He feels that the findings in the article are based on "flawed assumptions" and were not conclusive.
Dr. Boone agrees with the article's authors, Dr. David Brenner and Dr. Eric Hall, that CT scans should only be used judiciously and when medically necessary.
He, however, fears that people may misconstrue the propositions in the article.
"(CT experts in the AAPM) feel that much of the message of this article may be misconstrued or misunderstood by the press or by the public who may not be experts in CT," he says.
In their article, Brenner and Hall suggested that the 62 million CT scans done in the US every year might soon be responsible for 2 per cent of all cancers, even though they save lives and speed diagnosis.
They also suggested that about a third of all CT scans conducted were unnecessary.
Responding to these propositions, Dr. Boone said that the method of determining risk used in the article had been derived from Japanese citizens who were exposed to large amounts of radiation during the atomic bomb attacks on Hiroshima and Nagasaki in World War II.
He said that the extrapolation of those extremely high radiation exposure rates down to the low CT exposures "remains very controversial".
Anther "significant flaw" in the article, according to Dr. Boone, was the attempt to compare the Japanese bomb victims to "patients receiving CT in the US in 2007."
"(The article) did not correct for the many underlying confounding age dependent variables that differ between (the Japanese population) and older Americans, such as the incidence of obesity and diabetes," he said.
Dr. Boone suggested that patients who had had CT scans or were slated for examination in the next few weeks "discuss with their physicians not only the radiation risks of the CT examination, but the risks of not having the diagnostic information that CT provides."
Although he agrees that Brenner and Hall are "esteemed scientists and respected experts in radiation risk . . . the conclusions of the Brenner article are based on statistics and many statistical assumptions (and not) on the actual observation of somebody dying from having a CT scan."