Standard instructions before getting an MRI (magnetic resonance imaging) scan: Remove any jewelry, watches or other metal items and tell doctors about such in-body metallics as artificial joints, pacemakers and surgical clips. But here's a new item for the pre-scan questionnaire: Are you trying to quit smoking?

Smoking Several reports have found that MRI machines have burned people wearing transdermal patches. An article in this month's American Journal of Nursing said a man wearing a NicoDerm patch complained of a burning pain during the MRI. The radiologist stopped the scan and a nurse found a second-degree burn under the man's patch. Last month the Food and Drug Administration reported that two other patients got burns under their nicotine patches during MRIs.

Foiled It turns out some patches have a thin layer of aluminized backing that conducts heat.

Which Patches Burn? Nicotine patches aren't the only ones with metallic components. The Institute for Safe Medication Practices also recommends pre-scanning removal of patches such as Androderm (which delivers testosterone), Transderm-nitro and Deponit (nitroglycerin), Habitrol, Transderm Scop (scopolamine) and Catapres-TTS (clonidine).

Which Don't? According to the Amy Karch, assistant professor of clinical nursing at the University of Rochester and author of the journal article, the foil is not found in contraceptive patches such as Ortho Evra or in Duragesic (fentanyl), used for pain. NicoDerm's clear patch is also foil-free.

Burn Prevention Emanuel Kanal, chairman of the American College of Radiology committee on MRI safety, said nicotine patches are no problem to remove and reattach. But he doesn't recommend removing other patches without consulting a doctor.

-- Elizabeth Agnvall