COMPUTATION OF THREE-DIMENSIONAL ELECTROMAGNETIC-FIELD DISTRIBUTIONS IN A HUMAN BODY USING THE WEAK FORM OF THE CGFFT METHOD

Abstract

The problem of the computation of electromagnetic-field distributions in a strongly inhomogeneous human body is formulated in terms of an integral equation over the body. A weak form of the integral equation is discussed, in which the spatial derivatives occurring in this equation are integrated analytically. The resulting equation can then be solved very efficiently using the advantageous combination of a conjugate-gradient iterative method and a fast Fourier technique (CGFFT). Numerical calculations have been carried out for a strongly inhomogeneous, lossy radially layered sphere. A comparison with the Mie-series solution shows that the present weak form of the CGFFT method yields accurate results. The absorbed power density inside a CAT-scan generated model of the body of one of the authors is computed. It demonstrates that the present method can be considered as a comparatively simple and efficient tool for solving electromagnetic wave- field problems in strongly inhomogeneous media. [Vol. 7, No. 2, pp. 26-42 (1992), Special lssue on Bioelectromagnetic Computations]