Some numerical methods for dosimetry: Extremely low frequencies to microwave frequencies


  • Om P. Gandhi


This paper describes some of the numerical methods that have been developed for calculations of induced electric fields, current densities, and specific absorption rates for anatomically based heterogeneous models of the human body with increasingly finer resolutions. These methods, namely, the impedance method and the finite difference time domain (FDTD) method, have been used for dosimetric calculations for a number of bioelectromagnetic problems for whole-body or partial-body exposures, for far-field or near-field sources, and for CW or transient fields. The paper gives detailed calculations for some recent applications such as currents induced in the user's body by the electromagnetic fields (emfs) of electric blankets using the impedance method, coupling of an ultrawideband pulse using the frequency-dependent FDTD method incorporating dispersive properties of the various tissues, and specific absorption rate distributions in the head for emfs of cellular telephones. Because of accurate modeling of tissue heterogeneities and shapes, these methods are likely to play an increasing role in emerging technologies with bioelectromagnetic concerns.