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Nano-coating To Make Implants MRI Safe

Posted by Hemos on from the advancing-the-field dept.

Makarand writes "Patients who have implants containing any kind of metal cannot be MRI scanned as the powerful electromagnetic radio waves can induce currents large enough to heat the metal in implants to over 70 C and damage surrounding tissue. Now, Biophan, a biomedical devices company, has developed a nano-coating material that can protect implants by preventing most of the radio waves from reaching the internal components of the implant by reflecting them. It's high electrical resistance also prevents currents from flowing around the implant's surface and heating any nearby body tissue. Biophan's coating is a mixture of poorly conducting nanoparticles held in an insulating matrix. The coating is a mere three micrometres thick and can cut the energy induced in an implant by 89 per cent."

3 of 56 comments (clear)

  1. Metal implants? by cperciva · · Score: 2, Insightful

    Like... dental fillings?

    Does anyone know what makes some metal implants worse than others? Is it just a question of size?

    --
    Tarsnap: Online backups for the truly paranoid
  2. I'm almost thinking it's a hose... by JCMay · · Score: 3, Insightful

    This has got to be a hose; a material can't be a "good reflector" and an insulator at the same time.

    Mr. Maxwell taught us that EM waves are reflected from conductors because any electric field that is tangential to a conductor causes charges to move to cancel out that field (thre can be no electric field inside a conductor). These moving charges are more commonly called "currents."

    Insulating materials do not stop radiating fields; your radio works inside your wood framed house, doesn't it? Light propagates through the glass front of your CRT from the phosphors on the inside of the tube, doesn't it?

    Seems to me that if they're worried about induced eddy current heating of the implants, would it not make more sense to use *better* conductors, not worse ones? Better conductors would have lower I-squared-R losses, resulting in less resistive heating. Take that implant, put a few micro-inches of copper on it, and then seal it up with something biologically intert (some plastic?).

  3. not a nano coating by Goldsmith · · Score: 2, Insightful

    The coating is a mere three micrometres thick

    I guess that would make it a microcoating?

    We have a usefull word for nanoparticles as well... molecules.