Analysis of Magnetic Field of MRI Device Taking Account of Anisotropy and Hysteresis

摘要

This paper presents a new method to simulate the magnetic characteristics of permanent magnet type of magnetic resonance imaging (MRI) device. The pulse currents in the gradient coils will introduce the effect of eddy currents and hysteresis in ferromagnetic material, which will worsen the quality of imaging. In order to reduce eddy currents in the ferromagnetic material, the passive shield made of Fe-Si lamination is used in MRI system. Anisotropy of the passive shield is considered. Combining Preisach model with finite element analysis, the hysteresis characteristic is simulated.