The clinical applications of ‘in-vivo’ measurements of dielectric properties of human tissue

Schwan¹ in his review of the electrical properties of tissue and cell suspensions, noted the wide frequency spectrum over which dispersion regions can be expected. The values of the dielectric constant at low frequencies were likely to be very high. Fricke and Morse² found that the capacitance of excised breast tumour tissue was very different from that of excised normal breast tissue. These two observations have provided the rationale for the production of a piece of equipment to make rapid measurements of dielectric properties over a wide frequency spectrum and to investigate its possible clinical value in the field of breast cancer. There has been much work on various forms of in-vivo dielectric measurement, although they have usually been made in terms of electrical impendance, this work has been reviewed by Nyboer³ and by Markovich.⁴