Nuclear resonance apparatus including means for rotating the gradient of a magnetic field

Claim 2

Nuclear magnetic resonance ("NMR") apparatus for measuring the NMR of a specified atomic nucleus in a body, including magnet apparatus for generating a compound magnetic field having a specified configuration around the body, oscillator apparatus for applying an oscillating electromagnetic field to the body, and means for detecting NMR signals from the body and for reconstructing a display on the basis of the NMR signals, characterised by a magnetic field controller arranged to cause the magnetic field to rotate around the body to provide a scanning effect.

Claim 3

Nuclear magnetic resonance apparatus according to claim 1 for measuring the nuclear magnetic resonance of a specified atomic nucleus in a body, the apparatus comprising: a magnet apparatus for generating a homogeneous static magnetic field between its magnetic poles; shim means composed of a magnetic material mounted on each of said magnetic poles for applying a first gradient magnetic field intensity distribution in a direction perpendicular to the direction of the lines of magnetic force of the static magnetic field; electromagnetic apparatus for generating a second gradient magnetic field having a gradient magnetic field intensity distribution along said lines of magnetic force in superimposition with the static magnetic field for varying the magnetic field gradient of said first gradient magnetic field; an oscillator for generating an oscillating output having a frequency corresponding to the nuclear magnetic resonance condition of the atomic nucleus to be measured; a coil wound around the body to be examined for applying the output of said oscillator as electromagnetic waves to the body; a receiver for detecting the nuclear magnetic resonance signal received by the coil; a gradient magnetic field controller making a magnetic field line equivalent to the gradient magnetic field defined as the combination of the first gradient magnetic field generated by said magnet apparatus, as acted on by said shims, and the second gradient magnetic field generated by said electromagnetic apparatus, and for rotating the line along the section of the body to be examined by controlling said electromagnetic apparatus; a recorder for recording the nuclear magnetic resonance signal intensity detected by the receiver as to a plurality of directions of equivalent magnetic fields due to said gradient magnetic field controller in a manner to correspond to the position as to the direction perpendicular to said equivalent magnetic field line; a reconstructor for reconstructing the concentration distribution of the specific atomic nuclei in the section of the body on the basis of the nuclear magnetic resonance signal intensity as to a plurality of directions recorded in the recorder; and a display unit for depicting the result of the reconstruction by said reconstructor.

Claim 4

Nuclear magnetic resonance apparatus according to claim 2 wherein said gradient magnetic field electromagnetic apparatus includes an A.C. electromagnet apparatus generating an A.C. magnetic field in superimposition with the static magnetic field and wherein said controller issues signals to said recorder correlating data to correspond to the phase of said A.C. magnetic field.

Claim 5

Nuclear magnetic resonance apparatus according to claim 2 or 3 wherein the magnet apparatus generating the homogeneous static magnetic field includes electromagnetic apparatus driven by a D.C. stabilised power supply.

Claim 6

Nuclear magnetic resonance apparatus according to any preceding claim wherein the amplitude of the oscillating output of the oscillator is selectably variable so that the difference of the relaxation time of the specific atomic nuclei in a section of the body may be measured.

Claim 7

Nuclear magnetic resonance apparatus according to claim 1 or claim 2 wherein said oscillator includes means for generating pulsating high-frequency waves for use in obtaining free induction decay signals and wherein the reconstructor has means for reconstructing the concentration distribution of the specific atomic nuclei in the section of the body on the basis of said free induction decay signals.