title: Toward shielding improvements in MRI gradients and other systems.
abstract: A new method is described for reducing the shielding-error function in the 'supershielding' approach to designing MRI systems. The method is thus shown to lead to significantly better shielding and better control of eddy current effects associated with gradient coils. To illustrate this technique, a set of results for a z-gradient coil is presented. A generalization to non-standard geometries can be made in a straightforward manner with the new method. The usefulness of the relationship of all fringe-field quantities to the shielding-error function is emphasized. The formal limit of perfect shielding in a 'least-squares' sense is shown for a simple strip-shield model along with a numerical eigenvalue study for comparison with the theoretical limit.
authors.affiliation: Department of Physics, Case Western Reserve University, Cleveland, OH 44106-7079, USA. rwb@po.cwru.edu
authors.forename: R W
authors.initials: RW
authors.lastname: Brown
authors.forename: Y-C N
authors.initials: YC
authors.lastname: Cheng
authors.forename: T P
authors.initials: TP
authors.lastname: Eagan
authors.forename: T K
authors.initials: TK
authors.lastname: Kidane
authors.forename: H
authors.initials: H
authors.lastname: Mathur
authors.forename: R G
authors.initials: RG
authors.lastname: Petschek
authors.forename: W G
authors.initials: WG
authors.lastname: Sherwin
authors.forename: S M
authors.initials: SM
authors.lastname: Shvartsman
authors.forename: J D
authors.initials: JD
authors.lastname: Willig
mesh_terms: D000465:Algorithms; D004574:Electromagnetic Fields; D004867:Equipment Design; D005583:Fourier Analysis; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods*; D015233:Models, Statistical; D008962:Models, Theoretical