Organ dosimetry for human exposure to non-uniform 60-Hz magnetic fields

This work presents a realistic numerical evaluation of the currents induced by strong 60-Hz magnetic fields in the body of a power-utility worker in three configurations representative of live-line conductor/hardware maintenance tasks. Two postures involve a single-phase two-wire transmission line bundle. The third involves a more complicated three-phase conductor system in an underground vault. A current of 500 A is assumed in each conductor. The calculations employ a well-verified computer code applied to an anatomically derived heterogeneous conductivity model of the human body. The model voxel size (3.6-mm edges) is sufficiently high to resolve all major body components, as well as many smaller organs. The electric field and current density vectors associated with every voxel are calculated, permitting the computation of organ-specific dosimetric quantities such as spatial and temporal maximum and average values. For the two transmission line configurations, it is found that local peak values of the induced current density can exceed the commonly used standard threshold of 10 mAm/sup -2/ by a factor of up to 3-4, but the associated spatial averages do not exceed this threshold for any tissue. For the underground vault case, the spatial maxima in all tissues are below the threshold.