Modelling the electrical properties of tissue as a porous medium.
Models of the electrical properties of biological tissue have been the subject of many studies. These models have sought to explain aspects of the dielectric dispersion of tissue. This paper develops a mathematical model of the complex permittivity of tissue as a function of frequency f, in the range 10(4) < f < 10(7) Hz, which is derived from a formulation used to describe the complex permittivity of porous media. The model introduces two parameters, porosity and percolation probability, to the description of the electrical properties of any tissue which comprises a random arrangement of cells. The complex permittivity for a plausible porosity and percolation probability distribution is calculated and compared with the published measured electrical properties of liver tissue. Broad agreement with the experimental data is noted. It is suggested that future detailed experimental measurements should be undertaken to validate the model. The model may be a more convenient method of parameterizing the electrical properties of biological tissue and subsequent measurement of these parameters in a range of tissues may yield information of biological and clinical significance.
Smye
S W
SW
Department of Medical Physics and Engineering, Leeds Teaching Hospitals, St James's University Hospital, Leeds LS9 7TF, UK. SWSmye@leeds.ac.uk <SWSmye@leeds.ac.uk>
Evans
C J
CJ
Robinson
M P
MP
Sleeman
B D
BD
D000818:Animals; D003198:Computer Simulation; D017097:Electric Impedance; D004574:Electromagnetic Fields; D006801:Humans; D008954:Models, Biological; D016062:Porosity