Thermal ablation in biological tissue using tubular electrode

Saline‐enhanced RF ablation on a cholangiocarcinoma: a numerical simulation

“…The material properties required for solving the models considered in this work were obtained from the literature Antunes et al (2010c), Tziafalia et al (2006), Saline-enhanced RF ablation Haemmerich et al (2001) and Haemmerich et al (2003b) and are summarized in Tables I and II. For the electrical conductivity of the outer sections of the tumor it was considered a value of 0.269 S/m Haemmerich et al (2003b).…”

“…In the present work it was considered ks varying from 1 (no saline solution) to 5. Finally, the electrical conductivity of liver tissue is 0.13 S/m Antunes et al (2010c). The electrical conductivities of the healthy and tumor tissues were considered temperaturedependent, increasing 2 percent per degree celcius, dropping to 0.01 S/m above 1008C, allowing this way to simulate the electrical insulation veried when gas forms at this temperature value Haemmerich et al (2003a).…”

“…As nitinol stents can be used to reduce stricture problems of the bile duct, these can be also considered as potential electrodes for hyperthermia treatments. Previous works Antunes et al (2010a), Antunes et al (2010b) and Antunes et al (2010c) show that nitinol stents can be considered as a feasible solution for delivering radiofrequency (RF) energy in a tumor located in a hollow organ. However, the tissue lesion induced using this kind of electrode is not completely uniform due to the convective heat transfer associated to the blood perfusion in the portal vein and hepatic artery.…”

Using a tubular electrode for radiofrequency ablation

“…The numerical simulation of the models consists of the analysis of a thermoelectrical coupled field problem. The temperature at each point of the tissue can be expressed by a simplified bioheat equation (Antunes et al , 2010a, b): Equation 1 where ρ is the density (kg/m 3 ), c is the specific heat (J/kg · K), T is the temperature (K), k is thermal conductivity (W/m · K), J is the current density (A/m) and E is the electric field intensity (V/m). The right most term of equation (1) corresponds to the electrode energy.…”

“…On the other hand, these kind of electrodes are hard to apply in tumors that are located in hollow organs, like the esophagus, colon or bile duct. For these cases, previous work showed that, besides a SEMS can be used not only as a part of mechanical palliative procedure, it can be used as an electrode itself (Antunes et al , 2010a, b).…”