中国物理B ›› 2010, Vol. 19 ›› Issue (7): 78702-078702.doi: 10.1088/1674-1056/19/7/078702

• • 上一篇    下一篇

Active ferromagnetic shimming of the permanent magnet for magnetic resonance imaging scanner

唐昕, 洪礼明, 俎栋林   

  1. Institute of Heavy Ion Physics, Beijing Key Laboratory of Medical Physics and Engineering, School of Physics, Peking University, Beijing 100871, China
  • 修回日期:2009-11-21 出版日期:2010-07-15 发布日期:2010-07-15
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 60871001).

Active ferromagnetic shimming of the permanent magnet for magnetic resonance imaging scanner

Tang Xin (唐昕), Hong Li-Ming (洪礼明), Zu Dong-Lin (俎栋林)   

  1. Institute of Heavy Ion Physics, Beijing Key Laboratory of Medical Physics and Engineering, School of Physics, Peking University, Beijing 100871, China
  • Revised:2009-11-21 Online:2010-07-15 Published:2010-07-15
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 60871001).

摘要: This paper presents an approach of active ferromagnetic shimming for C-type permanent magnetic resonance imaging (MRI) magnet. It is designed to reduce inhomogeneity of magnetostatic field of C-type permanent magnet to meet the stringent requirement for MRI applications. An optimal configuration (locations and thicknesses) of active ferromagnetic pieces is generated through calculation according to the initial field map and the demanded final homogeneity specifications. This approach uses a minimisation technique which makes the sum of squared magnetic moment minimum to restrict the amount of the active ferromagnetic material used and the maximal thickness of pieces stacked at each hole location in the shimming boards. Simulation and experimental results verify that the method is valid and efficient.

Abstract: This paper presents an approach of active ferromagnetic shimming for C-type permanent magnetic resonance imaging (MRI) magnet. It is designed to reduce inhomogeneity of magnetostatic field of C-type permanent magnet to meet the stringent requirement for MRI applications. An optimal configuration (locations and thicknesses) of active ferromagnetic pieces is generated through calculation according to the initial field map and the demanded final homogeneity specifications. This approach uses a minimisation technique which makes the sum of squared magnetic moment minimum to restrict the amount of the active ferromagnetic material used and the maximal thickness of pieces stacked at each hole location in the shimming boards. Simulation and experimental results verify that the method is valid and efficient.

Key words: magnetic resonance imaging, active ferromagnetic shimming, permanent magnet, NdFeB pieces

中图分类号:  (Saturation moments and magnetic susceptibilities)

  • 75.30.Cr
75.50.Ww (Permanent magnets) 87.61.-c (Magnetic resonance imaging)