Low eddy current and low hysteresis magnet pole faces in MR imaging
AssigneeGeneral Electric Company
InventorWilliam Daniel Barber
Life of this patent
Estimating the term…
Abstract
Pole faces for an open magnetic resonance (MR) imaging system are constructed from a number of blocks having laminate sheets. The laminate sheets of the blocks are aligned, such that they are parallel to the flux of an applied time-changing magnetic field. Each laminate sheet is constructed of an amorphous material such that there is no predominant magnetic field alignment. This construction reduces eddy currents induced in the pole faces, and reduces residual magnetization, thereby reducing artifacts in an acquired image.
Claims18
An `open` magnetic resonance (MR) imaging system exhibiting reduced artifacts having at least pole pieces each having a substantially planar pole face opposite each other bounding an imaging volume, a magnetic excitation means having at least one excitation coil and pole pieces, the pole faces comprising:
- a plurality of magnetic blocks comprised of laminate sheets separated by, and held together with, a substrate, with each sheet aligned substantially parallel to the pole face, with each of the sheets comprised of an amorphous ferromagnetic material.
A magnetic flux conduit for receiving magnetic flux from a pole piece and for preferentially directing magnetic flux in each of an X, Y and Z direction, comprising:
- a pole face comprised of a plurality of layers, each layer comprising blocks of laminate sheets spaced from each other in each of the X and Y directions to match a predefined magnetic permeability in that direction.
Dependencies are inferred from the claim text.