Whole-body Scans More Marketing Than Science, Say Medical
Uncertain benefits, high costs, relatively high radiation
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
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
"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
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
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
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
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.
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.
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,
"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.
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For more information contact:
The American Association of
Physicists in Medicine
Headquartered in College Park, Maryland, the AAPM is an educational
organization devoted to the discipline of physics in medicine.
American Institute of Physics
American Institute of Physics
Professor of Radiology, University of California-San Francisco
St. Joseph Mercy Hospital
Ann Arbor, MI
John M. Boone,
UC Davis Medical Center
For more information:
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