CT扫描增加得癌风险

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Report Links Increased Cancer Risk to CT Scans

美联社报道
By THE ASSOCIATED PRESS
Published: November 29, 2007

Millions of Americans, especially children, are needlessly getting dangerous radiation from “super X-rays” that raise the risk of cancer and are increasingly used to diagnose medical problems, a new report warns. In a few decades, as many as 2 percent of cancers in the United States may be due to radiation from CT scans given now, according to the report.

The risk from a single CT, or computed tomography, scan to an individual is small. But “we are very concerned about the built-up public health risk over a long period of time,” said Eric J. Hall, who wrote the report with David J. Brenner, a fellow Columbia University medical physicist.

It was published in The New England Journal of Medicine today, and the study was paid for by federal grants. Some experts say that estimate is overly alarming. But they agree with the need to curb these tests particularly in children, who are more susceptible to radiation and more likely to develop cancer from it.

“There are some serious concerns about the methodology used,” but the authors “have brought to attention some real serious potential public health issues,” said Dr. Arl Van Moore Jr., chairman of the American College of Radiology’s board of chancellors.

The average American’s total radiation exposure has nearly doubled since 1980, largely because of CT scans. About 62 million scans were done in the United States last year, up from three million in 1980. More than four million were in children.

Since previous studies suggest that a third of diagnostic tests are unnecessary, that means that 20 million adults and more than one million children having CT scans are needlessly being put at risk, the authors write.