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Regulators at the Food and Drug Administration
(FDA) are concerned that the growing popularity of high-tech
computerized body imaging for health screening could be exposing
the public to risky levels of radiation.
Recent advances in computerized tomography
(CT) technology have increased the efficiency and lowered
the price of the scans. The changes have helped spawn a new
nationwide industry of unregulated boutique clinics where
patients pay $300 to $500
of their own money to get CT scans not for diagnosis,
but for regular health screening.
The agency is worried that easily available
screening with CT has the potential
of exposing patients to unhealthy repeat doses of the X-ray
radiation the machines use to form images. While
FDA evaluates the safety and effectiveness of CT scanners
and other medical devices for regular use, it has no power
to regulate how those machines are used once they reach doctors
offices.
Whole-body scans require higher doses
of the X-ray radiation CT scanners use to make images. As
more and more people visit clinics to be screened for lung
cancer, heart disease and other ailments, they could be absorbing
more radiation more often than the FDA originally intended.
It's
an open free-for-all in many communities. There
is a perception by the public that CT scanning is a benign
thing.
The average whole-body CT scan delivers
0.2 to 2.0 rads of radiation,
depending on the size of the patient's body. Studies of Japanese
survivors of the US atomic attacks on Hiroshima and Nagasaki
in WWII linked an increased risk of cancer to lifetime cumulative
exposures of 5 to 20 rads.
At 2 rads
per exam, we're not far from potentially dangerous radiation
doses.
Most doctors who work with CT scanners
know to monitor the cumulative radiation doses patients receive.
Professional societies also put out guidelines designed to
promote the safe and effective use of the machines. But the
self-pay nature of many CT boutiques allows patients to visit
several different clinics as often as they like.
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