Design of shimming rings for small permanent MRI magnet using sensitivity-analysis-based particle swarm optimization algorithm

Cheng, Yiyuan, He, Wei, Xia, Ling and Liu, Feng (2015) Design of shimming rings for small permanent MRI magnet using sensitivity-analysis-based particle swarm optimization algorithm. Journal of Medical and Biological Engineering, 35 4: 448-454. doi:10.1007/s40846-015-0051-6


Author Cheng, Yiyuan
He, Wei
Xia, Ling
Liu, Feng
Title Design of shimming rings for small permanent MRI magnet using sensitivity-analysis-based particle swarm optimization algorithm
Journal name Journal of Medical and Biological Engineering   Check publisher's open access policy
ISSN 2199-4757
1609-0985
Publication date 2015-08
Year available 2015
Sub-type Article (original research)
DOI 10.1007/s40846-015-0051-6
Open Access Status Not Open Access
Volume 35
Issue 4
Start page 448
End page 454
Total pages 7
Place of publication Heidelberg, Germany
Publisher Springer
Collection year 2016
Language eng
Abstract The main magnet in a magnetic resonance imaging (MRI) system creates a static magnetic field that determines the final imaging quality. In a permanent MRI system, shimming rings are commonly used to improve field homogeneity. However, the optimization of the ring structure is challenging owing to the nonlinear properties of the ferromagnetic material. To design a small permanent magnet system, this study explores the application of sensitivity analysis (SA) and particle swarm optimization (PSO) algorithm for the optimization of shimming rings. SA is used to identify the most important parameter of the shimming rings that affects the quality of the magnetic field to simplify the optimization process and improve optimization accuracy and efficiency. PSO is used to solve the complex and nonlinear optimizations of the magnetic field. To illustrate the effectiveness of the proposed method, a specific permanent MRI magnet was modeled. The results show that the inner radius of the shimming ring crucially affects magnetic field quality, with ring height having relatively smaller impact. Compared with the PSO-only optimization procedure, the combined SA-PSO optimization more rapidly converges to a better solution. The optimized shimming rings significantly improve the magnetic field uniformity (~10 fold) compared with that of the initial magnet without shimming rings.
Keyword Magnetic resonance imaging
Permanent magnet
Shimming ring
Sensitivity analysis
Particle swarm optimization
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2016 Collection
School of Information Technology and Electrical Engineering Publications
 
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