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Long range MRI scan

  1. Sep 27, 2012 #1
    So I want to know if MRI scan can be performed from a distance away. As far as I know MRI consists of a magnetic field to realign the hydrogen atoms in our body. After this the radio frequency pulse is applied and this energy is absorbed by some of the protons. When the radio frequency pulse is turned off the atoms go into a relaxation state releasing the energy as EM radiation or radio waves. This radio wave is then received by the receiver coil and translate back to an image by MRI scanner.
    My question is, is it possible to do this using maser to realign the atoms in our body from a distance, but then the radio frequency given off from the subject is too weak to be received by an antenna from a distance as explained in wiki ( http://en.wikipedia.org/wiki/Radiofrequency_coil ). Is there a way to strengthen such a signal so it can be received far away. I know electromagnetic radiation consists of electric field and magnetic field and is made up of photons. So if there's a way to strengthen the electric field property and make the subject's hydrogen atom produce a stronger signal.
     
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  3. Sep 28, 2012 #2

    mfb

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    What do you mean by "far away"? I think the first issue would be the magnetic field. 2-5 Tesla field strength is possible within those devices (some experimental setups can reach even more), but achieving the same field strength 1m+ away requires a much more massive setup.

    The signal is better if you cool the object (not useful with living material), have a higher field strength (see above) or more sensitive receivers.
     
  4. Sep 28, 2012 #3
    If the target is 1m+ away, how would you setup the device to generate a magnetic field that would reach the target? I think my understanding is that the electromagnetic field contains the magnetic field component. So by directing multiple maser, which generates electromagnetic waves, at the target, an electromagnetic field can be produced this way. The target should be living if I want to receive an image of its internal structure and MRI uses a coil receiver to measure the radio waves coming from the relaxation state of the atoms, so I want to know how you would go about receiving the radio wave if there is no receiver coil placed around the target.
     
  5. Sep 28, 2012 #4

    mfb

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    You need two different sources of magnetic fields:
    - a permanent magnetic field of the order of some Tesla. To get that field strength far away from the coils itself, you need very big coils, similar to the LHC detector magnets. See http://www.weltmaschine.de/sites/site_weltmaschine/content/e161/e163/e678/0511013_01-A4-at-144-dpi.jpg [Broken] for example - the magnetic field is produced in the orange-striped pipes, and there is a human in the image to compare its size. The LHCb magnet is quite massive, too.
    - quick radio frequency signals. They are not critical, you can send them from somewhere else

    If your receiver coil is not around the target, only some fraction of the signal will reach it - this reduces image quality or requires more time for the same quality.
     
    Last edited by a moderator: May 6, 2017
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