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Imaging apparatus using nuclear magnetic resonance

  • US 4,625,171 A
  • Filed: 02/14/1984
  • Issued: 11/25/1986
  • Est. Priority Date: 02/14/1983
  • Status: Expired due to Fees
First Claim
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1. An imaging apparatus for obtaining a nuclear spin distribution image of an object along a two-dimensional section, comprising:

  • means for generating a static magnetic field which has an intensity error distribution along said two-dimensional section;

    exciting means for repeatedly exciting nuclear spins in said object by repeatedly applying a pulsive high frequency magnetic field;

    means for generating a gradient magnetic field successively along each of a plurality of different directions across said two-dimensional section to produce frequency dispersion of nuclear spins along each of the directions;

    signal detecting means for detecting nuclear magnetic resonance signals induced during generation of said gradient magnetic field for a plurality of different directions thereof;

    memory means for storing data of said intensity error distribution of said static magnetic field;

    computer means for performing operations for each of said nuclear magnetic resonance signals detected by said signal detecting means to reconstruct an image in accordance with at least data read out from said memory means, said computer means performing the operations of analyzing a frequency spectrum of each of said nuclear magnetic resonance signals to obtain a projection along a frequency axis, and projecting back a value of said projection at each frequency to each picture point of said image to be reconstructed, said frequency being a resonance signal at said image point, said computer means correcting a frequency error of said frequency caused by said intensity error distribution of said static magnetic field in accordance with data read out from said memory means; and

    display means responsive to said computer means for displaying the reconstructed image.

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