Passive shimming for the 9.4 T whole-body MRI superconducting magnet

Wenchen Wang; Hongyi Qu; Yaohui Wang; Hui Wang; Junsheng Cheng; Cong Wang; Huafang Wu; Feng Liu

doi:10.1063/5.0167006

Passive shimming for the 9.4 T whole-body MRI superconducting magnet

Rev Sci Instrum. 2023 Dec 1;94(12):123703. doi: 10.1063/5.0167006.

Authors

Wenchen Wang¹, Hongyi Qu², Yaohui Wang², Hui Wang², Junsheng Cheng², Cong Wang², Huafang Wu³, Feng Liu¹

Affiliations

¹ School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, QLD 4072, Australia.
² Institute of Electrical Engineering, CAS, P.O. Box 2703, Beijing 100190, People's Republic of China.
³ Ganjiang Innovation Academy, CAS, Ganzhou 341000, People's Republic of China.

PMID: 38095541
DOI: 10.1063/5.0167006

Abstract

A superconducting magnet with a warm-bore size of 800 mm and a center magnetic field of 9.4 T for the whole-body magnetic resonance imaging (MRI) system was developed in IEECAS, China. To achieve a highly homogeneous magnetic field over the 400 mm diameter of spherical volume (DSV), both active shimming and passive shimming techniques were employed. This paper mainly focuses on the implementation of passive shimming for the 9.4 T MRI magnet system. After four iterations, we were able to achieve peak-to-peak and root mean square field homogeneities over the DSV at 3.05 and 0.94 ppm, respectively. In addition, this paper analyzes the electromagnetic forces and system errors of passive shimming for ultra-high fields, providing valuable insights into MRI magnet engineering.