Assessment of exposure to spatially varying magnetic fields in MRI environments: modelling analysis for simulation tools

Magnetic resonance imaging (MRI) is a non-invasive diagnostic technique widely used in medicine with more than 60 million exams per year performed worldwide. MRI personnel are always exposed to static and spatially heterogeneous magnetic fields (fringe or stray fields) and motion-induced time-varying magnetic fields during the working day. This kind of exposure can evoke vertigo and other sensory perceptions such as nausea, visual sensations, and a metallic taste which are not considered hazardous per se, but can be disturbing and may impair working ability. Up to now, no standardized procedures have been available in the literature for the assessment of occupational exposure in MRI environment. The goal of this paper is to give some indications about the analytical models underlying the develop of digital tool for occupational exposure assessment in MRI environments, to have easy but interactive educational tools, for educating MRI staff to avoid higher risk conditions, and draw up best practices. Analysis of the models for the estimation of the magnetic field spatial distribution and for the representation of the workers movements is described and finally some recommendations for an accurate methodology to use in simulation tools for exposure assessment are given.