April 2010

Editor's Note
A Measured Approach

By Jim Knaub
Radiology Today
Vol. 11 No. 4 P. 5

What you can’t measure you can’t know. Rebecca Smith-Bindman, MD, has spent considerable time applying that scientific premise to radiation dose in CT scans. In an exclusive interview published on page 16, she discusses research that measured and found tremendous variation in the amount of radiation patients were exposed to during CT scans.

Unless you’ve been weaving rugs in a monastery in Nepal for the past year, you have probably seen the alarming headlines and frightening news stories about patients receiving excessive doses of radiation during scans or radiation therapy. Cases with such flagrant errors are mercifully rare, but Smith-Bindman focuses on the less-dramatic unnecessary patient exposures that still present a subtle, real risk to patients. The trouble is that exposure really hasn’t been measured.

“I think unless you can start measuring dose [patients receive], there’s no way you can even understand the magnitude of the problem,” Smith-Bindman told Radiology Today.

And when she and her colleagues measured, they found great variation in the does patients receive from CT scans. Understanding why it varies so much is the next step.

“To put this into context, we’ve seen the same kinds of variations for many tests,” she says. “The problem here is that the levels of doses are so much higher for CT—100-fold higher, 500-fold higher than an x-ray—that we can’t afford that kind of variation for CT scans. It’s one thing to have variation in a low-dose study. It’s not acceptable to have variation in a high-dose study.”

With an estimated 70 million-plus CT exams performed in the United States annually, understanding what causes the variation—and what can be done to minimize dose—is clearly important. Smith-Bindman’s interview offers interesting thoughts on this key issue in radiology.

Also in this issue, Beth W. Orenstein writes about radiology’s role in appropriate imaging, and we have coverage from the recent Society of Interventional Radiology conference in Tampa, Fla.

Enjoy the issue.