The overuse of CT scans could be causing 14,500 cancer deaths a year, according to two studies published today. Researchers found that machines varied widely in how much radiation they exposed patients to, often leading to big, hidden risk. A typical chest scan, for example, is the equivalent of about 100 chest X-rays, but in some hospitals, machines were doling out four times as much radiation.
That means that while the absolute risk of cancer for any given patient may be small, the vast number of scans performed every year—more than 70 million, 23 times the number in 1980—will ultimately cause lots of cancer. “There is far more radiation from medical CT scans than has been recognized previously,” says the doctor who edits the Archives of Internal Medicine, where the studies were published.