Surface transmission probe for noninvasive measurements of dielectric properties of organ tissues at frequencies between 1 MHz and 300 MHz.

A probe is described for determining the dielectric permittivity and dielectric loss of organ tissues at very high frequencies (VHF) in a non-violating manner. Instead of the usual reflection coefficient measurement, with this probe the electromagnetic wave transmission coefficient is measured between two coplanar electrodes on the organ surface which are capacitively coupled by the electric fringing fields extending into the organ. An appropriately constructed transmission probe can sense the dielectric behaviour of tissue into deeper organ regions than a reflection probe of corresponding size. Results are reported of transmission probe measurements on various liquids with known dielectric properties for the purpose of probe testing and on a pig liver during ischemia.