Shim coils used in magnetic resonance imaging and NMR to produce magnetic fields are commonly designed to generate spherical harmonics, and thus achieve accuracy over a spherical region. Herein a cylindrical basis set is presented as an alternative to spherical harmonics, so as to better suit the cylindrical coil geometry and, in cases where it more closely matches a cylinder, the imaging region of interest. Example coil winding patterns for a selection of functions in this new set are derived using the target field method. A computational approach is taken to determine their accuracy, and it is found the basis functions are generated with high accuracy over cylindrical imaging regions within the coil. The basis set is also applied to a double-coil configuration with active shielding, which results in slightly reduced accuracy within the coil but highly effective field nullification beyond the coil radius.

Item Type:	Refereed Article
Keywords:	cylindrical basis, shim coil design, target field method, MRI
Research Division:	Engineering
Research Group:	Biomedical engineering
Research Field:	Medical devices
Objective Division:	Expanding Knowledge
Objective Group:	Expanding knowledge
Objective Field:	Expanding knowledge in the mathematical sciences
UTAS Author:	Phair, A (Mr Andrew Phair)
UTAS Author:	Brideson, M (Dr Michael Brideson)
UTAS Author:	Forbes, LK (Professor Larry Forbes)
ID Code:	130168
Year Published:	2018
Web of Science® Times Cited:	4
Deposited By:	Mathematics and Physics
Deposited On:	2019-01-14
Last Modified:	2019-03-21
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