FDA Raises Body Scan Safety Issue
Food and Drug Administration officials are worried that the growing popularity of full-body scans for early health screening may be exposing thousands of Americans to unnecessary and potentially dangerous radiation.
Facilities offering full-body computed tomography, or CT, examinations, which are heavily advertised and expensive, are sprouting nationwide, luring affluent consumers who think they are buying peace of mind with the promise of early warning for cancers, heart problems and other diseases.
But in fact, FDA officials say, clinics and other facilities are giving healthy consumers higher-than-conventional doses of radiation that are unlikely to do any good.
There is little the FDA can do about it, however. After the agency has approved medical devices for any purpose, it has no authority to regulate their use. The FDA approved the scanning devices to peer into individual sites on the body where illness is suspected, but it cannot stop doctors from using them for full-body scans.
“Some of these people are in the business to scan anybody who comes through the door,” said Dr. Thomas B. Shope of the FDA’s center for devices and radiological health.
The advanced technology, which is part X-ray and part computer, produces three-dimensional images of the inside of a person’s body. The images are clearer than X-rays provide, and they make it possible to detect abnormalities earlier. The image quality is so high in part because of the higher radiation levels.
But for people without symptoms, many doctors believe the risks from the radiation more than offset the benefits from the unlikely detection of some types of early cancers or other diseases. Moreover, experts note that suspicious but ultimately harmless findings can trigger unnecessary testing and provoke needless anxiety.
“For an average Joe to walk in off the street and get himself screened from head to toe is probably a bad idea, especially if he isn’t in any risk group,” said Dr. John Cardella, chief of the radiology department at the State University of New York-Upstate Medical University in Syracuse, who served on an FDA advisory panel on the issue.
The scans emit far more radiation than conventional X-rays; for example, a CT scan of the chest delivers 100 times the radiation of a conventional chest X-ray. And “you are doing more of the body at one time,” Shope said.
Most physicians are not likely to prescribe full-body scans for their patients, because studies have not proved them effective.
Consumers typically decide on their own to get them and pay premium prices--as much as $1,300 in some facilities. Because the procedure is not covered by insurance, there are no records to show how many such scans are being performed nationwide.
But magazines and Web sites are flooded with ads promoting such scans as a way to catch health problems early. There are several clinics in Southern California.
Jon Hyman, a spokesman for Virtual Physical, a Baltimore-based facility, predicted that within five years, rigorous academic studies will have demonstrated that full-body scans’ benefits outweigh the radiation risks.
“We are saving lives,” he said. “We think five years from now this will become common practice, that every adult will get a full-body scan and it will be covered by insurance.”
Hyman dismissed the notion that clinic operators were motivated by the scans’ moneymaking potential. “We see it as a successful business, but so is heart surgery,” he said. “A heart surgeon makes thousands every time he opens up a person’s chest, but he’s saving a life.”
Even the effectiveness of targeted CT screening in at-risk populations is still under investigation. New York state, for example, is funding a study on whether CT scanning is effective in detecting lung cancer among smokers.
“This is one of the first such studies, and the concept of whole-body scanning to detect cancers or other disease in low-risk populations has clearly not been established and likely never will,” Cardella said.
The FDA could require manufacturers to design devices that would emit vastly lower levels of radiation, but the agency is unlikely to do so because “the image quality would be less, and would decrease the utility for those patients who really need it for focused areas,” Cardella said.
The FDA is likely to require manufacturers to provide radiologists and technicians with more specific information on the radiation levels they deliver to patients.
There is no known threshold of safety for a single radiation exposure, but cumulative exposure over a lifetime raises the risk of developing cancer. This is why the American College of Radiology recommends that diagnostic exposure be kept as low as possible.
The dangers of radiation exposure are well known from studies of atom bomb survivors, radiation therapy patients and radiation accidents.
Some studies have linked the potential of developing cancer to a cumulative lifetime exposure of 5 to 20 rads of radiation; the CT scanners can deliver 0.2 to 2 rads of radiation during a single full-body scan, depending on a patient’s body size.
“Each exposure raises your probability of developing cancer,” Shope said. “It’s worrisome in the sense of widespread population exposure. We worry about these ‘boutiques’ that offer the procedure, where there is no indication that you really need it.”
