AIP 75th Anniversary - Home
home contact us sitemap
Inside Science News Service
More information:

Ben Stein
American Institute of Physics
301-209-3091

Craig Smith
American Institute of Physics
301-209-3088

ISNS home ISNS archive about ISNS contact us


Whole-body Scans More Marketing Than Science, Say Medical Physicists

Uncertain benefits, high costs, relatively high radiation are concerns

College Park, MD (August 26, 2002)--Medical entrepreneurs have been aggressively marketing whole-body scans by promising preventive medicine and implying peace of mind. But experts in medical radiation say there are no scientifically demonstrated benefits of the scans and many reasons to avoid them.

In the past few years, people with money and general concerns about their health--a group that some have coined the "worried wealthy"--have been shelling out hundreds of dollars or more for the whole-body scan, which is also advertised as the "full body" or "total body" scan. In the procedure, customers get a 3-D x-ray--or "CT scan"--of the body, typically from the pelvis to the neck (head scans usually sold separately). Whole-body CT scans, promise the ads, can reveal hidden medical problems that doctors can treat early.

Experts skeptical
But more and more medical and scientific organizations are raising doubts about the procedure. A group with expertise in the physics of medical radiation--the American Association of Physicists in Medicine (AAPM)--is the latest to speak out.

"It's not a question of 'Can I afford this?' but instead 'Do I really need it?'" says Robert Gould, president of the AAPM and a professor of radiology at the University of California at San Francisco. "You have to have a better criterion than the color of your credit card," he adds.

"The procedure does carry a certain risk," Gould says, "and we're not dealing with a trivial amount of radiation. There's no demonstrable benefit from receiving that amount of radiation."

Fishing for problems before there are symptoms
By speaking out on whole-body scans, the medical physicists of AAPM are joining ranks with the American Heart Association, the American College of Cardiology, the American College of Radiology, and state agencies in Pennsylvania and Texas. In a statement (http://www.aapm.org/announcements/CT.html), AAPM says that total-body scanning is "not scientifically justified" for patients without symptoms.

According to the authors of the statement, no scientific data shows whole-body scanning to be effective in detecting disease. According to the AAPM experts, CT scans are best for obtaining information on known or physician-suspected problems, like a head injury or a previously detected cancer, rather than search healthy patients for unknown diseases.

More risk than reward
With no scientifically documented benefits, whole-body scans have many potential drawbacks and even some risks, medical physicists say. These include:
--Relatively high radiation exposure
--High cost that insurance will not cover

These same critics suspect that whole-body scans also produce:
--A heightened risk of "false positives" that can lead to needless surgeries and potential complications
--Unnecessary medical expenses for insurance companies, which may pass these costs onto consumers

Lack of scientific data on the procedure
Advertisements for full-body scans typically contain testimonials of patients who found diseases early and say the procedure saved their lives.

"But such data is anecdotal," says John Boone, a UC-Davis medical physicist and chief draftsman of the AAPM policy statement on CT body scanning. Boone says that the lack of scientifically rigorous studies on whole-body screening scans suggests that individuals should think long and hard before considering having such an exam or giving one as a gift.

"These are hard studies to do," Gould acknowledges. A rigorous scientific study of the procedure might be problematic for several reasons, including the ethical issue of exposing low-risk individuals to relatively high amounts of medical radiation. But researchers can potentially explore simpler questions about whole-body scans, he says, and no one is doing this.

Radiation concerns
Radiation exposure is AAPM's main concern. Whole-body scans expose a person to "significant radiation exposures" for a diagnostic medical procedure, in the words of the AAPM statement. In general, medical professionals avoid exposing patients to radiation, unless the potential benefits outweigh the small risk from the radiation. But the benefits of whole-body scans are unknown, since no scientific data on this question exist, points out medical physicist Ralph Lieto, the chair of the AAPM Radiation Protection Committee, which wrote the statement on whole-body scanning. The risk that x-rays damage DNA in healthy cells and cause cancer in later years increases with dose.

Small as this risk may be, whole-body CT scans deliver significantly higher radiation doses than other x-ray procedures. While a standard chest x-ray takes a single snapshot of the body, a CT scanner takes multiple snapshots as it rotates around the patient. What's more, the full-body scan takes pictures along the length of the body, rather than in just a targeted region.

Unproven benefit
As a result, a typical whole-body CT scan may deliver an "effective" radiation dose about 250 times greater (15 millisieverts) than a patient receives in a chest x-ray, estimates AAPM president Gould. "Effective dose" is a measurement of the risk that radiation poses to the body. It takes into account the amount of radiation delivered to each body region and each region's sensitivity to radiation.

Physicians usually use CT scans for highly targeted purposes, like examining a previously detected tumor in a particular part of the body. Doctors are investigating CT "screening"---scanning to find an unknown problem, but only for very narrow uses and high-risk groups, like checking smokers' lungs for signs of lung cancer. The studies are still underway even for these narrow applications.

False alarms
Critics also worry that whole-body scans may increase the possibility of "false positives" ---frightening false alarms that may prompt more expensive tests, even surgery that could risk complications.

What would be nice, says AAPM's Gould, is a scientific study that could track how many false positives full-body scans actually produce. Such studies could resolve questions about how many false alarms the tests may generate.

High cost
Another concern is cost. Not covered by insurance, the scans require an out-of-pocket expense of typically between $500-1200, depending upon how much of the body is scanned.

Insurance costs
Whole-body scans may also pump up needless medical expenses for the health-care industry, says AAPM's Boone. Even though the patient pays for the whole-body scan, he says, the doctor may ask the patient's insurance company to pay for additional tests when a suspicious area is found - even though the overwhelming majority of these will be subsequently shown to be of no concern.

Approving such procedures costs money for the insurance company, which may have to pass the cost onto consumers as higher premiums, Boone says.

"There's a whole rippling-down effect in medical costs," agrees AAPM president Gould.

Thumbs down for now
Since there is no scientific study which has demonstrated the efficacy of whole-body screening scans at this time, these experts suggest that individuals wait until credible data becomes available or consult with their physician before making the decision to have a screening CT scan.

## ## ##

For more information contact:

The American Association of Physicists in Medicine
Headquartered in College Park, Maryland, the AAPM is an educational nonprofit
organization devoted to the discipline of physics in medicine.

Ben Stein
American Institute of Physics
301-209-3091

Craig Smith
American Institute of Physics
301-209-3088

AAPM Experts:

Robert Gould, PhD
President, AAPM
Professor of Radiology, University of California-San Francisco
(415) 476-1962

Ralph Lieto, MS
St. Joseph Mercy Hospital
Ann Arbor, MI
(734) 712-8746

John M. Boone, PhD
UC Davis Medical Center
Sacramento, CA
916-734-3158

For more information:

American Association of Physicists in Medicine Policy Statement on Whole-Body CT Scans

FDA Center for Devices and Radiological Health's Page on Whole-Body Scanning