Study Looks at CT Scans, Cancer Risk

Animal Model Suggests Increased Risk for People with Cancer Susceptibility Genes

Newswise — WINSTON-SALEM, N.C., -- Dec. 14, 2011 -- From the doctor’s office to the airport, Americans have more opportunity for radiation exposure than ever before.

While low levels of radiation are used in medical imaging and airport body scanners, there is much debate about exposure levels and potential cancer risks. New research from Wake Forest Baptist Medical Center has found that there could be an increased risk of cancer for certain individuals who are exposed to multiple CT scans.

The research, published in the December issue of the journal Radiation Research, was the first to look at how CT scans affected mice specially bred with a lung cancer-susceptibility gene known as Ki-ras. Mutations in this gene have been implicated in about 30 percent of a common form of human lung cancer. In this study, mice that expressed the mutant Ki-ras gene were exposed to low-dose helical computed tomography (CT) radiation. The mice exposed to CT radiation had 43 percent more tumors than unirradiated mice, and females were more susceptible than males.

We believe we are the first to use an animal model in an actual clinical CT scanner to directly look at the risk of producing tumors after a diagnostic procedure,” said lead researchers Michael T. Munley, Ph.D., associate professor of radiation oncology, and Mark S. Miller, Ph.D., professor of cancer biology, at Wake Forest Baptist. “What we found is that there may be an increased risk of tumor formation from CT scans in certain individuals with cancer susceptibility.”

source: Newswise