Electrical conductivity measurement in thiel-embalmed tissue model: relevance to radiofrequency ablation

Thiel-embalmed human cadaveric specimens are used widely for biomedical scientific investigation. This Letter reports electrical impedance measurements of Thiel-embalming solutions from 1 Hz to 32 MHz. Compared with other solutions studied, Thiel solution has the lowest impedance throughout the test spectrum. The electrical conductivity of a Thiel-embalmed liver sample exhibited a relatively flat frequency response from 100 to 500 kHz, which is the frequency range used for electro-surgery and radiofrequency tumour ablation (RFA). It measured 5 Sm^-1 compared with 0.22 Sm^-1 obtained from ex-vivo fresh pig liver. Using finite element modelling and experimental evaluation, the ablation zone obtained from the Thiel-embalmed liver sample was extremely small due to its much higher conductivity. Hence, it is concluded that Thiel-embalmed tissue cannot be used as a reliable model for RFA evaluation.