New Development of Monohedral Magnet for MRI Using the Combination of Genetic Algorithm and FEM-NESM

A novel monohedral permanent magnet (PM) configuration is suggested and geometrically optimized to have higher magnetic efficiency as well as higher degree of access to imaging region of a magnetic resonance imaging (MRI) system. The configuration has a pair of main PMs magnetized in the opposite directions, respectively. The geometry of the main PMs is optimized by using genetic algorithm combined with a novel flexible magnetic field analysis method which combines finite-element method and new-type equivalent source method. Through an optimal design, the suggested PM configuration is proven to provide a sufficiently homogeneous and strong magnetic field for MRI application.