The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 26, 1988
Filed:
Feb. 27, 1987
Gary H Glover, Delafield, WI (US);
Grant T Gullberg, Salt Lake City, UT (US);
General Electric Company, Milwaukee, WI (US);
Abstract
A method for shimming a magnet in a nuclear magnetic resonance (NMR) system employs measurements of the magnetic field obtained from chemical shift imaging (CSI) of a homogeneous phantom. The data are acquired, in one embodiment, in four planes parallel to, and rotated about, the axis of the magnet. A special volume subset of data are expanded in an orthonormal basis set (associated Legendre polynomials in one embodiment) for N+1 separate experiments, where N is the number of shim coils to be adjusted. The result is an N.times.N matrix of calibration coefficients for the shim coil set and a vector of shim current changes which must be applied to null out the measured field inhomogeneity.