Simulation of induced current densities in the human body at industrial induction heating frequencies

At industrial workplaces in the vicinity of induction heating and melting devices, workers are exposed to strong magnetic fields. Up until now, little knowledge about the coupling of external fields into the human body at low frequencies existed. This paper provides numerical investigations to clarify the ratio between external homogeneous magnetic fields and induced current densities inside the human body in the frequency range from 250 Hz up to 10 kHz. The finite-difference time-domain (FDTD) method is used to calculate the induced current density in a realistic inhomogeneous 1 cm resolution human body model with appropriate tissue parameters. The magnitude of the external magnetic field equals the reference value for occupational exposure in the current guideline of the International Commission on Nonionizing Radiation Protection (ICNIRP). It was found that the calculated maximum current densities inside the body may exceed the basic restrictions of the ICNIRP guideline at least up to a factor of two. Finally, the suitability of the human body model for dosimetric investigations is discussed in view of fine-resolution models presented in the literature