Why Whole-Body
Scans Are A Bad Idea
(February
2002)
By Maryann Napoli
"Why wait for symptoms to occur?" The radio ad
is pitching the latest example of how entrepreneurial America's
medical care system has become.
Whole-body scans are now advertised to healthy people along
with the idea that finding disease early can be nothing
but beneficial.
The use of scanners to screen people for heart disease and
cancer before the appearance of symptoms is relatively new.
Until the last few years, such expensive, high-tech equipment
was reserved solely for diagnosis-as the last-resort, state-of-the-art
method for diagnosing people whose symptoms require further
investigation. This has begun to change dramatically with
a trend that started on the West Coast. Centers with names
like AmeriScan and Imaging for Life have opened in large
cities. Their popularity got a major boost when Oprah Winfrey
enthusiastically described her own whole-body scan experience
on national TV last year.
Billed as a "high-tech medical check-up," the
scans are costly, ranging from about $300 for a lung scan
to $1,000 for the whole body. People typically go for scanning
without a doctor's recommendation; and they usually pay
out of pocket, as most insurance companies do not cover
these tests. And rightly so. The use of scanners as screening
tests is a bad idea for two reasons: false alarms and too
much radiation. This article will explore radiation risk
only because many past issues of HealthFacts have addressed
other harms caused by screening, including unnecessary biopsies,
unnecessary cancer treatment, and false reassurance. Many
organs of the body, most notably, the breast and prostate,
harbor small cancers that would safely remained dormant
had they never been discovered and surgically removed. Similar
concerns about overtreatment apply to finding blockages
in the coronary arteries of symptomless people.
CT scans involve much higher doses of radiation than standard
x-rays because they provide three-dimensional, multiple
"slices" of the body. A CT chest scan, for example,
involves about 400 times the radiation dose of a single
chest x-ray. A CT scan of the abdomen or pelvis involves
a radiation dose 500 times that of a chest x-ray. The 2000
European Commission Directorate-General for the Environment
reported these dose estimates based on surveys of diagnostic
medical tests conducted at hundreds of hospitals in the
1990s.
There is no equivalent U.S. agency that provides similar
effective-dose guidelines for tests involving radiation
exposure. Nor do we have an independent agency that regulates
the use of CT scanners. The consumer is left with the radiologist's
word regarding low-dose equipment claims. There is no inspection
of these scanning centers as there is for mammography facilities,
which are regulated by the Food and Drug Administration.
The FDA sends warning letters to the mammography facilities
whose equipment is found to emit higher than necessary radiation
and shuts down any facility whose equipment is known to
emit excessively high radiation.
All x-ray and scanning facilities should get this kind of
oversight, but they don't. The FDA is currently considering
the issue of regulation, according to Thomas B. Shope, Jr.,
PhD, of the FDA's Center for Devices and Radiological Health.
In a telephone interview, Dr. Shope said that radiologists
at these new scanning centers are, in effect, selling a
service that is "off label," which means that
CT scans are intended for diagnostic purposes but not for
screening symptomless people. Furthermore, there is no requirement
for the manufacturers to prove their equipment is safe and
effective for this new use. All scanners are "grandfathered"
because the original CT scanning equipment came on the market
before 1976, when the FDA first began requiring proof of
safety and efficacy for medical devices.
As a result, the new scanners with their purported improvements
of high resolution and low-dosage are merely cleared by
the FDA, as opposed to approved. The latter entails a more
rigorous review to prove safety and efficacy, which is similar
to that required of a new drug or medical device.
To receive FDA clearance, Dr. Shope explained, the equipment
manufacturers merely had to show that their machines are
equivalent to the older CT scanner in dose and image quality.
Much more rigorous FDA oversight is long overdue. Last year,
a small survey of hospitals in the Midwest showed that children
undergoing CT scans were exposed to adult doses of radiation
that were higher than necessary to produce good image quality.
The scanning centers are allowed to get away with misleading
advertising. As things stand now, the FDA cannot challenge
even the most obvious erroneous claim, unless the equipment
brand and model number is identified in the ad. All a scanning
center has to do is avoid mention of this information, and
they are free to mislead us all they want.
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Maryann Napoli is the associate director of the Center
for Medical Consumers in New York City
