I discussed the issue of too many CT scans in this month's diagnosis SDI- this article on the same topic was posted today on the acor list-

"Radiation Exposure from CT Scanning
An abdominal CT delivers about 50 times as much radiation to the stomach as=20=
a=20
conventional x-ray.

Journal Watch does not ordinarily cover review articles, but a recent New=20
England Journal of Medicine article on radiation exposure from computed=20
tomography =E2=80=94 written by radiology researchers at Columbia University=
 =E2=80=94 received so=20
much media attention that a brief summary seems appropriate.
Numbers of CT scans have increased dramatically in the U.S. =E2=80=94 both f=
or=20
diagnosing symptomatic patients and for heart, lung, colon, and whole-body s=
creening=20
in asymptomatic people. In pediatric populations, faster scanning times (les=
s=20
than a second in some cases) are partly responsible for increased CT use.
Typical organ doses of radiation are much larger with CT than with=20
conventional radiography; for example, an abdominal CT delivers about 50 tim=
es more=20
radiation to the stomach than conventional x-ray. Based on data correlating=20
radiation exposure and subsequent cancer rates among Japanese survivors of a=
tomic=20
bombs, the authors estimate that 1.5% to 2.0% of cancers in the U.S. might b=
e=20
attributable to CT radiation. However, direct epidemiologic data on=20
CT-associated cancer are not yet available. Notably, a recent survey suggest=
ed that many=20
physicians are oblivious to radiation doses and potential risks associated w=
ith=20
CT (Radiology 2004; 231:393).
Comment: Although computed tomography represents an extraordinary advance in=
=20
diagnostic radiology, the authors correctly note that CT scans are ordered=20
excessively, often repeated unnecessarily, and enlisted in the practice of=20
defensive medicine. The authors present three approaches to reducing overall=
=20
radiation exposure from CT in the population: Reduce radiation doses in indi=
vidual=20
studies (which can be done with modern scanners), substitute ultrasonography=
 and=20
magnetic resonance imaging for CT when possible, and order CT studies only=20
when medically necessary.
=E2=80=94 Allan S. Brett, MD"