Complex Permittivity Differences Between Normal and Pathological Tissues: Mechanisms and Medical Significance

The complex permittivity dispersions of normal and pathological biological tissues are surveyed from audio to microwave frequencies. The mechanisms responsible for producing changes to biodlelectric properties are examined, and qualitative and quantitative predictions are made about these changes following the transformation of normal to malignant tissue. For the transformation of rat liver to hepatoma tissue, we predict a peak increase of 73% at 2 MHz for the permittivity, with elevations in conductivity relatively constant at 40-46% between 3 MHz-lGHz. Several features of the predictions are in accord with experimental measurements previously published. Transformed biodielectrlc properties are of potential significance for tissue characterization, medical imaging, diagnosis and therapy.