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

Purpose Magnetic resonance–compatible medical devices operate within the MR environment while benefitting from the superior anatomic information of MRI. Avoiding electromagnetic interference between such instrumentation and the MR system is crucial. In this work, various shieldingconfigurations for positron emission tomography (PET) detectors were studied and analyzed regarding radiofrequency (RF) shielding effectivenessand gradient-induced eddy currentperformances. However, the results of this work apply to shieldingconsiderations for any MR-compatible devices. Methods Six shieldingenclosure configurations with various thicknesses, patterns, and materials were designed: solid and segmented copper, phosphor bronzemesh (PBM), and carbon fiber composite (CFC). A series of tests was performed on RF shielding effectivenessand the gradient-induced eddy current. Results For the shielding effectiveness, the solid copper with various thickness and PBM configurations yield significantly better shielding effectiveness(>15 dB) compared with CFC and segmented configurations. For the gradient-induced eddy currentperformance, the solid copper shieldingconfigurations with different thicknesses showed significantly worse results, up to a factor of 3.89 dB, compared with the segmented copper, PBM, and the CFC configurations. Conclusions We evaluated the RF shielding effectivenessand the gradient-induced eddy currentartifacts of several shieldingdesigns, and only the PBM showed positive outcomes for both aspects. Magn Reson Med 79:1745–1752, 2018. © 2017 International Society for Magnetic Resonance in Medicine.