use of CT scans has increased from 3 million in 1980 to 70 million in 2007. According
to a recent article in Medpage Today, 2 studies showed that radiation from CT
scans were at higher levels than previously believed. According to one study which consisted of data on CT radiation from four San Fransisco hospitals:
“median effective doses ranged from 2 mSv for a routine head scan
to 31 mSv for a multiphase abdomen and pelvis scan, according to Rebecca
Smith-Bindman, MD, of the University
of California San Francisco,
Radiation doses as low as 10 mSv have been linked to an
increased cancer risk among survivors of the Hiroshima and Nagasaki atomic bomb
blasts, the researchers reported in the Dec. 14/28 Archives
of Internal Medicine.”
From these studies, it is believed that young people are
more at risk due to their rapidly dividing cells.
The second study “projected that
29,000 future cancers will be directly attributable to CT scans performed in
2007. Furthermore, it was estimated that of the 29,000 projected cancers
— or about 2% of all cancer diagnoses — most were expected to be caused by
scans of the abdomen and pelvis (14,000), chest (4,100), and head (4,000).
About 2,700 would be caused by CT coronary angiography. The most commonly
caused cancers would be those of the lung (6,200) and colon (3,500), as well as
leukemia (2,800). “
Estimates of radiation exposure where
done by a retro perspective analysis and the reported results were as follows:
A single multiphase abdomen and pelvis CT scan equaled the
radiation for 74 mammograms and 442
conventional chest X-ray series, and a CT coronary angiogram equaled about 15
mammography series to the breast and the 711 chest X-rays to the lungs.
Some critics disagree with the benefits vs. risk ratio with CT scans. They claim that the studies were based on various assumptions that may not be true, such that those receiving CT
scans had the same life expectancy as those not receiving scans. Furthermore, some believe that CT scans value to detect and help diagnosis cancers not found with other
procedures should not be discounted.
Link for Dr. Mercola’s
article with John Gofman, MD, PhD, and nuclear physicist, on Xrays and Cancer.