Diagnostic Radiation Is Dangerous

Patients may tend to think that imaging studies are harmless. They may be relatively so, but it doesn't mean their risks are nonexistent.

One of the great medical technologies of today is imaging, allowing physicians to look inside the body noninvasively. Medicine would not be the same without x-ray, ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and nuclear imaging.

We often forget that these imaging modalities involve radiation, which is harmful to the body's tissues at an adequate dose. Efforts are always made to minimize the dose, and if the necessary dose for good imaging is actually dangerous, it wouldn't even be in clinical practice. But one factor is sometimes overlooked: a patient may have multiple studies, and the total cumulative dose may no longer be safe.

Some people believe in good health so much that they're willing to have a CT or MRI scan of the whole body just to screen for whatever is there. Certain diseases have great benefit in screening, like colon cancer. But why undergo high doses of x-ray with a CT scan, now believed to boost cancer risk with multiple uses, when many other diseases manifest with symptoms, if they occur at all? You may argue that certain conditions are deadly without early warning signs. Unfortunately, the disease must be common enough to be worth screening a population.

Then there is imaging without any medical necessity, like vanity ultrasound. For pregnant women, ultrasound is used to evaluate the condition of the fetus. It is not for taking pictures to keep in a photo album, as some women may consider. Whether ultrasound waves are truly harmless is unknown, but it's better to play it safe.

The bottom line is that the radiation per imaging study may be within safety limits, but it can add up with multiple studies, especially unnecessary ones. Reserve this technology for medical necessity, where the consequences of no imaging are far greater than the risk of radiation.