Posted on: Tuesday, August 31, 2004

High cancer risk seen from whole-body CT scans

By Thomas H. Maugh II and Daniel Costello
Los Angeles Times

Whole-body CT scans, long controversial because of doubts about their ability to find hidden disease, can significantly increase the risk of developing cancer, according to a new study.

The radiation from a single whole-body scan is equal to that from 100 mammograms, and similar to that received by survivors of the atomic bombings of Hiroshima and Nagasaki, 1.5 miles from the explosion, says radiation biologist David J. Brenner of Columbia University.

The radiation from one scan is enough to produce one tumor per every 1,200 people who undergo the procedure, report Brenner and co-author Carl D. Elliston of Columbia in yesterday's issue of the journal Radiology.

For those who have annual scans, the risk goes as high as one tumor per every 50 people.

"The risks for a single scan are not huge," Brenner said. "But if you have them repeatedly, the risk starts to build up quite a lot, and becomes quite significant."

Brenner cautioned that his results apply only to healthy people. "The risk-benefit equation changes dramatically for adults who are referred for CT exams for medical diagnosis," he said. "Diagnostic benefits far outweigh the risks."

Computerized tomography scans are produced with X-rays that travel from head to toe, spiraling around the body. Computer programs integrate the data to produce highly detailed three-dimensional images of the body.

The tests, which cost $800 to $1,500, are heavily advertised as being able to detect hidden diseases, especially cancers, and have surged in popularity since they were first used in the mid-1990s.

The procedure reached a peak of 32 million scans in 2002.

Bruce Friedman of Heart Check America, one of the largest centers in Los Angeles, said the study means "it is worth talking about the risks as well as the benefits."

Although 15 percent of his business is whole-body scans, "I have never had a full-body scan," he said, "and I wouldn't recommend one to anyone I know who doesn't have a reason to think they are sick."

Most major health organizations, including the Food and Drug Administration, American Cancer Society, Environmental Protection Agency and American College of Radiology, recommend against elective whole-body scans.