Am I Exposed to Any Radiation During an MRI scan?

MRIs use radio waves

A patient is loaded into an MRI machine.
A patient is loaded into an MRI machine. Blend Images - ERproductions Ltd/Getty Images

The short answer is "no." You're not exposed to any significant amount of radiation during an MRI (magnetic resonance imaging) scan.

For those of us with multiple sclerosis (MS), MRI scans are a regular occurrence. Most of us probably have one annually, with additional ones ordered if the neurologist suspects a relapse, our symptoms worsen drastically, or if we are participating in a clinical trial of some sort.

Most certainly, we had at least one MRI when we were in the process of being diagnosed with MS.

What is an MRI?

We are not exposed to any radiation at all during an MRI scan. “MRI” stands for “magnetic resonance imaging,” and it uses magnetic and radio waves to produce images — not radiation.

For a simplified description of how MRIs are made: Extremely strong radio waves (10,000 to 30,000 times stronger than the magnetic pull of the earth) are sent through the body. This temporarily moves the nuclei of the (primarily hydrogen) atoms that make up the body’s cells. When they move back, they emit their own radio waves, which are captured by the scanner.

While it is freaky to think about magnetic waves that strong being sent through your body, there is no risk at all to your body’s tissues during an MRI scan. If you have any implanted devices that contain metal, they could malfunction or cause a problem, so it is essential that you inform your technician of the presence of any device, screw, plate or anything else that you have in your body that you were not born with.

The only possible danger from an MRI is a tiny risk of allergic reaction to gadolinium, the contrast material that is used in people with MS, which usually is mild. Also, people with kidney dysfunction are at risk for a more serious condition, called nephrogenic systemic fibrosis, caused by gadolinium.

Putting Medical Radiation in Perspective

While you may worry about radiation from medical tests like CT scans, think about this: we are surrounded by radiation. Our electronic society, full of computers, cell phones, and televisions, expose us to radiation everyday. And consider that when you fly in a plane coast to coast you absorb the same amount of radiation as you do having your chest x-rayed.

There it is — a long answer to the short question about whether we have to worry about radiation exposure during MRIs. Ultimately, if you are consider about your exposure to radiation during any of your tests, talk to your doctor. Together you can weigh the benefits and the risks. Usually the former is greater than the latter when discussing MRI, but that is a conclusion that the two of you can come to together.

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