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Cecily had a pacemaker installed some time ago and all 3 docs Heart-Neuro-GP) said no MRI - also the heart doc said not to use a cellular phone as some of them have a strong enough field to affect the pacemaker. - the intensity of the field falls off with the square of the distance and holding a cellular phone normally puts the field very close to the PM. Bob Anibal ----- Original Message ----- From: J. R. Bruman <[log in to unmask]> To: <[log in to unmask]> Sent: Sunday, October 24, 1999 5:03 PM Subject: Re: PD-Re: MRIs > P&B Fahr wrote: > > > > I believe your statement should be that there can be no > > "magnetic object" as opposed to "metal object". Many > > metal objects are not magnetic such as aluminum, copper, > > silver, gold, and stainless steel. I believe a metal > > object has to contain iron or an iron alloy to be > > magnetic. > > the MRI scanner employs such a powerful field that the > > subject can't have any > > metal object on or in his body) > > Without entering a discussion of physics of little interest to other > listmembers: In this case it's the shape rather than the material that > is important. When the magnetic field around any electrical conductor > changes, an electric current results (for example, the copper wire coils > in a generator). If any metal object in your body happens to be the > wrong shape, elongated or coiled, its current or internal heat might > conceivably injure surrounding tissue. I've had MRIs despite numerous > crowns and fillings in my teeth, without ill effect, but the MRI techs > generally are cautious about any other internal metal. Cheers, > Joe > -- > J. R. Bruman (818) 789-3694 > 3527 Cody Road > Sherman Oaks, CA 91403-5013 >