Spatial-varying Magnetic Field Evaluation during Activities in an NMR Laboratory

Nuclear Magnetic Resonance (NMR) systems, vital in both academic and industrial labs, pose inherent risks from increasingly strong static magnetic fields, radiofrequency (RF) fields, and spatial magnetic field gradients. To address these electromagnetic hazards, the EU and ICNIRP have defined worker exposure limits. This research focused on assessing risks in a typical NMR lab, specifically for workers with Active Implantable Medical Devices (AIMDs). We precisely measured the static magnetic field around an 11.7 Tesla NMR spectrometer and computationally modeled the electric field induced in operators by their movements. Our analysis showed that all calculated exposure parameters were below legislative limits for acute occupational exposure. However, a critical finding was that the static magnetic field exposure exceeded the action level for AIMD wearers during tasks requiring close proximity to the spectrometer. This highlights a significant safety concern, demanding specific protocols for this vulnerable group.