Three-dimensional optimization of correction iron pieces for open high field MRI system

We have developed a new magnet for open high field (0.7 T) MRI systems. In order to homogenize magnetic fields in the field of view, an optimization method to determine initial configurations of large correction iron pieces was developed. In our method, we combined linear programming (LP) and 3D magnetic FEA and, using analytic formulae for LP, we computed field harmonics due to the volume of magnetized iron.