[ RadSafe ] CT scans and cancer

[Steven Dapra]

Nov. 28, 2007

         According to an Associated Press report, the authors of a "Current 
Concepts" review article on CT scans in the New England Journal of Medicine 
believe that "In a few decades, as many as 2 percent of all cancers in the 
United States might be due to radiation from CT scans given now."  (The 
direct quote is from the AP article, not from the review article.  I found 
out that this is a Current Concepts review article by clicking on this link 
at the end of the AP article <http://content.nejm.org/>.  It takes you to 
the NEJOM website.)

         The link to the AP article (on Yahoo) is 
<http://news.yahoo.com/s/ap/20071129/ap_on_he_me/dangerous_scans>.

Title of the review article is "Computed Tomography  An Increasing Source 
of Radiation Exposure," by David J. Brenner, Ph.D., D.Sc., and Eric J. 
Hall, D.Phil., D.Sc., from the Center for Radiological Research, Columbia 
University Medical Center, New York.  It was published in the New England 
Journal of Medicine.  The citation is Volume 357:2277-2284, November 29, 
2007; Number 22.

         You can go to this link <http://content.nejm.org/> and click in 
the germane places and buy a copy on line for $10.00.  (There is no charge 
for subscribers.)

         Below are some quotes from the AP article.

The risk from a single CT, or computed tomography, scan to an individual is 
small. But "we are very concerned about the built-up public health risk 
over a long period of time," said Eric J. Hall, who wrote the report with 
fellow Columbia University medical physicist David J. Brenner.

It was published in Thursday's New England Journal of Medicine and paid for 
by federal grants.

CT scans became popular because they offer a quick, relatively cheap and 
painless way to get 3D pictures so detailed they give an almost surgical 
view into the body. Doctors use them to evaluate trauma, belly pain, 
seizures, chronic headaches, kidney stones and other woes, especially in 
busy emergency rooms. In kids, they are used to diagnose or rule out 
appendicitis.

But they put out a lot of radiation. A CT scan of the chest involves 10 to 
15 millisieverts (a measure of dose) versus 0.01 to 0.15 for a regular 
chest X-ray, 3 for a mammogram and a mere 0.005 for a dental X-ray.

[According to] Dr. Alan Brody, a radiologist at Cincinnati Children's 
Hospital Medical Center, three out of 10 parents in one study insisted on 
CT scans instead of observing the child's condition for awhile even after 
they were told of the radiation risk.  (Note:  The AP article does not 
present Brody's comment as a direct quote.  I re-arranged the AP article a 
little to make this quote.  It is an accurate representation of what Brody 
seems to have been paraphrased as saying.)

         A few of my own comments:

         Why are CT scans being used to diagnose appendicitis in 
children?  Why not do white blood cell counts; and do what is called 
"letting up" on the patient's abdomen?  (Those who have been "let up" on 
will know what I mean.)

         I think the description of exposure levels is confusing.

         What is with the 30 percent of pushy parents who want the scans 
done anyway?

Steven Dapra
sjd at swcp.com