Design method for realization of open-type magnetically shielded room combined with square cylinders made of magnetic material for MRI

摘要

To improve amenity for patients in hospitals, we have proposed an open-type magnetically shielded room (MSR) composed of magnetic and conductive cylinders for a magnetic resonance imaging (MRI). The design method of the opening part, that enables the leakage flux densities outside to be less than 0.5mT, is discussed taking account of magnetic saturation. First, the homogenization technique is applied to the design method of the opening part to reduce the number of elements for cylinders. Moreover, the magnetic characteristic of the opening part is assumed to be linear to obtain the ideal flux distribution. Next, the thickness of the magnetic cylinders is determined using the flux distribution in the real model reproduced from that in the homogeneous model so that the magnetic cylinders are not saturated. Finally, the design method is verified using the realized open-type MSR.