Two studies published on Tuesday have, for the first time, quantified the risk of America’s overuse of CT scans. The high levels of radiation involved may be responsible for 14,500 deaths a year. While CT scans give amazingly clear views of internal organs, they are far more radioactive than x-rays. The typical CT scan is the equivalent of 100 conventional x-rays, with some as intense as 440 x-rays. The United States overuses the technology on a scale not seen in countries such as Canada. Emergency rooms often ship patients off for a quick scan before even seeing a physician. Today, Americans get more than 70 million scans a year, 23 times the amount three decades ago. “The articles in this issue make clear that there is far more radiation from medical CT scans than has been recognized previously,” says Dr. Rita Redberg, the editor of the Archives of Internal Medicine.