Measurement of Electrical Impedance and Eddy Currents in Tissue Phantoms

Measurement of the electromagnetic (EM) properties of tissue such as electrical conductivity, permittivity, and eddy current characteristics can be used in clinical medicine for characterizing and distinguishing soft tissue morphology. Such measurements can yield complementary information to what can be obtained using analysis with an optical microscope. An example is the assessment of margins during the surgical resection of occult tumors. In current practice, the surgeon relies on pre-operative imaging modalities, sight and palpation to locate and attempt to fully resect the tumor(s). Frozen section pathological assessment offers the only other resource available to the surgeon for margin analysis, but it is incomplete because only a small fraction of the resected tissue is examined and it is often not feasible to wait for the results of the frozen section analysis before completing the surgery. This paper describes a characterization and imaging method based on variations in electromagnetic tissue properties to assess the surgical margins of resected tissues. This is noteworthy because accurate margin assessment has been shown to significantly improve long term patient outcomes[1].