MAGNETIC SHIELDING FOR MRI SUPERCONDUCTING MAGNETS

This paper describes an optimal design of a highly homogeneous superconducting coil system with magnetic shielding for Magnetic Resonance Imaging (MRI). The presented optimal design method, which is originally proposed in our earlier papers, is a combination of the hybrid finite element and boundary element method for analysis of an axially symmetric nonlinear open boundary magnetic field problem, and the mathematical programming method for solving the corresponding optimization problem. In this paper, the multi-objective goal programming method and the nonlinear least squares method have been adopted. The optimal design results of 1.5- and 4.7-Tesla-magnet systems with different types of magnetic shielding for whole-body imaging are compared and the advantages of a combination of active and yoke shields are shown.