Novel gradient coils designed using a boundary element method

Abstract

Boundary element methods offer a powerful approach for designing gradient coils, allowing the generation of coils wounds on arbitrarily shaped surface so as to produce any form of field variation that Is consistent with Maxwell's equations. These methods are based on meshing the current carrying surface into an array of boundary elements. In this work, we have extended boundary element methods that have previously been used used for coil design and integrated a powerful mesh generating program so as to produce coils with totally arbitrary geometry. Four examples are used to illustrate how the modified method provides a single versatile coil design protocol. These relate to the design of: i) shielded head gradients with highly asymmetric surface geometry that give the highest possible gradient field strengths; ii) very short, shielded gradient coils to allow improved access to the subject; iii) bi-planar coils generating highly asymmetric, stepped magnetic fields for use in fast imaging by multiple acquisition with micro-B0 arrays (MAMBA); iv) an insertable set of head gradient coils with shoulder cutouts. © 2007 Wiley Periodicals, Inc.