Design Method for Realization of Open-Type Magnetically Shielded Room Composed of Magnetic Square Cylinders for MRI

In order to increase amenity for hospital patients, we introduce an open-type magnetically shielded room (MSR) in tight space composed of magnetic and conductive cylinders for a magnetic resonance imaging (MRI). This paper presents a design for the MSR opening part for an actual 3T MRI that combines magnetic cylinders with magnetic mullions to decrease the leakage flux density to less than 0.5 mT, taking magnetic saturation into account. The design utilizes the homogenization technique to model the opening part which reduces the number of elements. Moreover, a newly optimized design approach is proposed for the design of openings. First, the opening part is designed while treating the magnetic property in linear analysis to obtain an ideal flux distribution without magnetic saturation. Then, the thickness of the magnetic cylinders is determined for magnetic cylinders to stay unsaturated. Finally, the open-type MSR presented in this paper is built in a hospital, and the design method is verified.