Radiation
from CT scans linked to cancers, deaths
CT scans deliver
far more radiation than has been believed
and may contribute to 29,000 new cancers each
year, along with 14,500 deaths, suggest two
studies in today's Archives of Internal Medicine.
One study, led by the National Cancer Institute's
Amy Berrington de Gonzalez, used existing
exposure data to estimate how many cancers
might be caused by CT scans.
Another study
in the journal suggests the problem may even
be worse. In that study, researchers found
that people may be exposed to up to four times
as much radiation as estimated by earlier
studies. While previous studies relied on
dummies equipped with sensors, authors of
the new paper studied 1,119 patients at four
San Francisco-area hospitals, says author
Rebecca-Smith Bindman of the University of
California-San Francisco. Based on those higher
measurements, a patient could get as much
radiation from one CT scan as 74 mammograms
or 442 chest X-rays, she says.
Young
people are at highest risk from excess radiation,
partly because they have many years ahead
of them in which cancers could develop,
Smith-Bindman says. Among 20-year-old women
who get one coronary angiogram, a CT scan
of the heart, one in 150 will develop cancer
related to the procedure.
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