Do you wear a transdermal patch, a patch stuck to your skin that contains medication? Or a nicotine patch while you're trying to quit smoking? Skin patches can be risky if you're also undergoing the diagnostic procedure known as MRI--magnetic resonance imaging.

Several dozen types of skin patches are now on the market. About a third of them contain metal as part of the patch backing on the side away from the skin. During an MRI, the metal can overheat and burn you. Not good.

The US Food and Drug Administration (aka FDA) has issued a warning about potential harm from the patches. If you wear a patch and are about to undergo an MRI, be sure to tell the MRI tech about the patch before you climb into the big machine. MRI facilities are supposed to be prepared to advise patients whether they need to remove transdermal patches and also how to take them off safely.

Here's the FDA Advisory.