Troy LaBounty, MD
Troy LaBounty, MD, assistant professor of medicine in the division of cardiology, Weill Cornell Medical College, and assistant attending physician, NewYork-Presbyterian Hospital, New York City.
Despite all we hear about the dangers of radiation in imaging tests, we can’t just stop using them — imaging tests often yield vital information. For instance, the cardiac CT scan used to diagnose coronary artery disease and estimate a person’s risk of having a heart attack can provide life-saving information… but this test often is cited as an example of one that needlessly exposes patients to excessive amounts of radiation. So it is excellent news to hear that there are new scanning techniques that cut radiation back — way back, in fact, by as much as 90% for some patients!
I called Troy LaBounty, MD, assistant professor of medicine in the division of cardiology at Weill Cornell Medical College and lead author of a new study that demonstrates how to combine a number of different radiation-reduction techniques to achieve this dramatically safer result. My goal was to learn how patients can be sure that they are getting the best cardiac CT with the least possible radiation dose.
For the study, Dr. LaBounty and his team at Weill Cornell wanted to see the effect of using four different radiation-reduction methodologies at the same time. The researchers administered beta-blocker medications (as needed) to slow the heart rate to less than 65 beats per minute so that images could be acquired with fewer “snapshots”… minimized the area being scanned… individualized radiation dosing for each patient’s heart rate and body mass index (BMI)… and took the minimum number of images that would be needed (as opposed to “padding” the total in case some images weren’t usable).
Researchers were trying to ascertain whether using these radiation-reduction methods would result in any loss of accuracy. The 81 patients in the study agreed to have both catheter angiography (in which a thin plastic tube is inserted into an artery through an incision, followed by injection of a radioactive contrast dye and x-ray visualization) and a cardiac CT. They were then divided into two groups — for one group, doctors used their usual standards for CT scanner settings, while for the other group they used all of the radiation-reducing techniques mentioned above. Researchers found that the dialed-back settings produced highly accurate CT scans, comparable to catheter angiogram (the gold standard) — even though they used almost 90% less radiation in the test group!
Dr. LaBounty told me that doctors are increasingly aware of both the need to reduce radiation and that it can be done with these techniques — though using all of them together remains a somewhat novel approach. If you need a CT scan, don’t hesitate to ask your doctor whether these protective measures will be taken and to ask the technician performing the scan what he/she is doing to minimize radiation.