Getting some rays

Computed tomography, a.k.a. the CAT scan or CT scan, uses a camera that rotates around the body to create a three-dimensional image of the body or body part it’s scanning. While it offers a more complete picture of what may be ailing you, it exposes you to more radiation than the conventional x-ray. A scan of your chest will give you eight mSv of radiation and of your abdomen or whole body ten mSv.

The MRI and the ultrasound, two other common diagnostic procedures, provide no radiation.

Too many tests?

As medical consumers we need to be watchful. If we go from doctor to doctor through our lifetime, no one may be keeping track of our total lifetime radiation exposure. Cancers can’t usually be definitively blamed on previous x-rays and CT scans that we got many years earlier. The more radiation that’s used the clearer the diagnostic image, so some worry that doctors use more than absolutely necessary. There seems to be a tricky balance.

But in any case diagnostic imaging of the radiation-producing type has increased for a variety of reasons, with use of CT scans quadrupling from 1996 to 2011. The trend is now leveling out, according to the marketing research and consulting firm IMV Medical Information Division.

The equipment is so expensive that some doctors may wish to order more tests, according to an article by Jane Brody in The New York Times, “to use it liberally to recoup the expense.” She adds that patients are often “pleased to receive thorough evaluations that involve the best cutting-edge technologies,” so they’re not complaining.

Proactive medical consumers may wish to question rather than blindly accept as they go along. For example, they could ask their physician or children’s physician to tell them the specific reason they need an x-ray or CT scan, if it’s not obvious to them, and if it’s necessary immediately or could be postponed. They might question how the results will diagnose the problem and affect treatment, or if there’s a lower-risk diagnostic tool that would work just as well.

To just refuse a test on general principle isn’t usually a good idea, however. Nor is asking for one if the physician doesn’t see the need.

Protect the little ones. Never have any kind of x-ray if you are pregnant or might be. Ask questions, such as whether your child can wear a lead apron over the parts of the body not being scanned. For more information see Image Gently from the Alliance for Radiation Safety in Pediatric Imaging at www.pedrad.org/associations/5364/ig/?page=591.

In most cases the benefit of diagnostic imaging makes up for the risk. But be as informed as you can be before you catch those rays.

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