SUSHI方法在梯度线圈设计中的应用。

Application of the SUSHI method to the design of gradient coils.

作者信息

Shvartsman S M, Brown R W, Cheng Y C, Eagan T P, Fujita H, Morich M A, Petropoulos L S, Willig J D

机构信息

Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, USA.

出版信息

Magn Reson Med. 2001 Jan;45(1):147-55. doi: 10.1002/1522-2594(200101)45:1<147::aid-mrm1019>3.0.co;2-b.

DOI:10.1002/1522-2594(200101)45:1<147::aid-mrm1019>3.0.co;2-b

PMID:11146496

Abstract

An approach to potential improvements in magnetic field shielding for a gradient coil system with cylindrical geometry is presented, utilizing "supershielding" conditions for the currents on both the primary and the secondary coils. It is demonstrated that the field can be strongly suppressed everywhere outside a cylindrical shield coil radius, even though the finite-length active shield only partially surrounds a primary coil. The supershielding method, which is aimed at controlling eddy currents, still has sufficient freedom to maintain the desired magnetic field behavior inside the imaging volume. The trade-off is an additional primary current oscillation and increased current peaks and field energy. This method has been applied to design short transverse and axial gradient coils, giving substantially improved shielding compared to an apodization method. Magn Reson Med 45:147-155, 2001.

摘要

本文提出了一种针对具有圆柱形几何形状的梯度线圈系统改进磁场屏蔽的方法，该方法利用了初级和次级线圈上电流的“超屏蔽”条件。结果表明，即使有限长度的有源屏蔽仅部分包围初级线圈，在圆柱形屏蔽线圈半径之外的任何地方，磁场都能被强烈抑制。旨在控制涡流的超屏蔽方法仍有足够的自由度来维持成像区域内所需的磁场特性。代价是初级电流会额外振荡，电流峰值和场能增加。该方法已应用于设计短横向和轴向梯度线圈，与变迹法相比，屏蔽效果有了显著改善。《磁共振医学》45:147 - 155, 2001年。