A cylindrically symmetric magnetic shield for a large‐bore 3.0 Tesla magnet

Abstract

A 3.0 Tesla, 0.80-m bore magnet replaced our previous 1.9 Tesla, 0.76-m magnet. The 3.0 Tesla replacement magnet had a dipole moment of 1.7 with respect to that of the 1.9 Tesla magnet. The pre-existing cylindrically symmetric passive steel shielding was modified to confine the fringe fields of the replacement magnet to match those of the previous magnet. A cylindrically symmetric inner shield insert of about 20,000 kg was designed, fabricated, and installed. Upon energization of the magnet, the combined shielding met all design criteria. Alternative designs, optimization of cylindrically symmetric designs, and costs of fabrication, are presented herein.

Low eddy current RF shielding enclosure designs for 3T MR applications

“…Magnetic resonance images are acquired by fast‐oscillating EM fields in a strong static magnetic field environment. To avoid EM interference, the inserted systems typically encapsulate electronic components inside a shielding Faraday enclosure to preserve the performances of both MRI and the inserted device . Without sufficient shielding designs, intense radiofrequency (RF) fields in the megahertz range could disturb the device electronics or, reciprocally, the noise generated from the device could corrupt the MRI image .…”