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Homework Help: Biophysics exam question

  1. Dec 16, 2012 #1
    19. Which imaging method is contraindicated (not allowed) for patients with a titanium dental
    a) CT b) MRI c) PET d) SPECT e) mammography

    I thought the answer was MRI, but the correct answer is PET. Can anyone explain why this is. Thanks.
  2. jcsd
  3. Dec 17, 2012 #2


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    Hi BrnoStudent! :smile:

    No-one else has answered, so I'll have a go …

    According to wikipedia (at http://en.wikipedia.org/wiki/Magnetic_resonance_imaging#Magnetic_field), there are two problems with metals under MRI: movement and heating.

    Titanium isn't ferromagnetic, so it won't move.

    But it's electrically conductive, so it can be heated by induction.

    (Though there are plenty of websites that contradict this, and say that titanium is safe for MRI … maybe it has something to do with the effect of heating on a tooth? :confused:)
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