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Tikhonov Regularization Approach for Acoustic Noise Reduction in an Asymmetric, Self-Shielded MRI Gradient Coil

Citation

Jackson, JM and Brideson, MA and Forbes, LK and Crozier, S, Tikhonov Regularization Approach for Acoustic Noise Reduction in an Asymmetric, Self-Shielded MRI Gradient Coil, Concepts in Magnetic Resonance. Part B , 37B, (3) pp. 167-179. ISSN 1552-5031 (2010) [Refereed Article]


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Copyright Statement

The definitive published version is available online at: http://interscience.wiley.com

DOI: doi:10.1002/cmr.b.20166

Abstract

We consider a mathematical method for minimizing the acoustic noise of self-shielded magnetic resonance imaging gradient coils designed to produce an asymmetrically located target field within a cylindrical chamber. During imaging, the gradient coils are being constantly switched on and off, subjecting the coil to large Lorentz forces. These forces cause the chamber to buckle, creating a pressure wave in the bore which manifests as acoustic noise at sound pressure levels up to about 130 dB. In this model, the linearized coil deflection, the pressure wave, and the acoustic noise level inside the chamber are all solved for in closed form. The closed-form nature of the solutions permits simple insights into the behavior of the system. Although reductions of only 0.6 dB were achieved, the method allows some flexibility if other design sacrifices are made. The gradient coil switching frequency plays a major role in the magnitude of the acoustic noise and is studied here. Results are presented for two basic switching functions for shielded gradient coils. Unshielded gradient coils, other switching functions, and other penalty functions can be easily accommodated using the method presented.

Item Details

Item Type:Refereed Article
Keywords:gradient coil; switching functions; Lorentz forces; acoustic noise reduction;
Research Division:Physical Sciences
Research Group:Other Physical Sciences
Research Field:Medical Physics
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Physical Sciences
Author:Jackson, JM (Mr James Jackson)
Author:Brideson, MA (Dr Michael Brideson)
Author:Forbes, LK (Professor Larry Forbes)
ID Code:64931
Year Published:2010
Web of Science® Times Cited:4
Deposited By:Mathematics and Physics
Deposited On:2010-09-16
Last Modified:2011-03-23
Downloads:0

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