Determining Gradient Imperfections in NMR Machines
Original Publication Date: 1986-Mar-01
Included in the Prior Art Database: 2005-Mar-08
In order to correct for the errors in Nuclear Magnetic Resonance (NMR) images due to magnetic inhomogeneities using the self-correcting techniques introduced in the article appearing in the IBM Technical Disclosure Bulletin 28, 4017-4018 (February 1986), one needs a priori determination of the inhomogeneity contributed by the gradients themselves. This article describes a technique to determine these. The following is an outline for the algorithm. We will determine functions A(x,y) and B(x,y) which represent the intensity of the inhomogeneities of the x and y gradients (extensions to three dimensional imaging are obvious), respectively. Step 1: Place an object which is susceptible to NMR excitation and had uniform mass in the bore of the magnet where a field mapping is desired.