Several media sources are reporting on concerns raised by scientists about the radiation dangers of CT scans. CT scans delivers the radiation exposure of about 400 chest x-rays. Their popularity for colon cancer screening and other diagnoses has increased the average American’s lifetime radiation exposure seven fold since 1980.  During that time, the number of CT scans performed in the U.S. has increased from 3 million to 70 million. The scientists say that the Food and Drug Administration (FDA) has failed to appreciate the risk of increasing cancer through radiation exposure.

On Tuesday, the FDA is convening a public meeting about the risks of America’s increased reliance on CT scans. A group of FDA whistleblowers plan to use the event to publicize concerns they say FDA managers have overlooked. The New York Times reports that they have received internal FDA documents showing that the FDA approved General Electric’s application to to use CT scans to screen for colon cancer — over repeated objections of FDA scientists. It reports that Dr. Julian Nicholas said that approving the application could “expose a number of Americans to a risk of radiation that is unwarranted and may lead to instances of solid organ abdominal cancer.”

In an AP story run by the Washington Post and Los Angeles Times reports that Dr. Nicholas lost his FDA job after he raised this concern. “Scientific and regulatory review process for medical devices was being distorted by managers who were not following the laws,” Nicholas told his superiors before his job was eliminated.

Tuesday’s FDA meeting comes after three California hospitals reported hundreds of acute radiation overdoses last year, with many patients reporting lost hair and skin redness, according to the AP story. It add that many studies have associated radiation exposure, of the type used in the CT scans, with cancers that can appear decades later.