A Novel Method to Predict the Maximum Electric Fields in Different Body Parts Exposed to Uniform Low-Frequency Magnetic Field

Thepermissible external field strength described in international exposure guidelines and standards was derived under the assumption that humans are exposed to a uniform field in free space. However, realistic field distributions are partial body exposure to the nonuniform field. Thus, the permissible field strength has overconservative values when applying the spatial peak strength to practical compliance assessment. In this study, we discuss the relationship between the uniform external magnetic field strength and induced electric field in different body part models to help set the permissible field strength for nonuniform magnetic field exposure. We proposed a formula for estimating induced electric field from the electromotive force of cuboid models based on Faraday's law. Then, we applied the formula to homogeneous ellipsoidal and homogeneous realistically shaped models. Furthermore, we investigated the effect of model inhomogeneity to confirm the difference in the induced electric field in anatomical body models. The homogeneous ellipsoidal model was comparable to the homogeneous realistically shaped model, whereas the model inhomogeneity led to an approximately 1.5 times increase in the computed maximum electric field strength.