# Simulation Study of Microwave Ablation of Porous Lung Tissue
## 3 Results
### Model Verification  
[PERSON] et al. [26] performed microwave ablation experiments on living pigs. The ablation power was set at 60 W, and the ablation was guided by a single-needle microwave antenna for 15 min. To verify the accuracy of the porous heat transfer model, we keep the simulation conditions consistent with those studied by [PERSON] et al.: an ablation power of 60 W, ablation time of 15 min, and tumor radius of 1 cm.  
The tissue temperatures obtained in the simulation for the porous model and the biological heat transfer model were compared with those obtained from in vivo experiments by [PERSON] et al. Table 3 demonstrates the tissue temperatures for the three cases at a distance of 20 mm from the microwave antenna. The tissue temperatures of the porous heat transfer model were 86.8 \({}^{\circ}\)C, 95.3 \({}^{\circ}\)C, 98.6 \({}^{\circ}\)C, and 103.8 \({}^{\circ}\)C for microwave ablation times of 8 min, 10 min, 11 min, and 12 min, respectively, and the tissue temperatures of the Pennes biological heat transfer model were 90.2 \({}^{\circ}\)C, 98.4 \({}^{\circ}\)C, 103.0 \({}^{\circ}\)C, and 108.4 \({}^{\circ}\)C, respectively. The tissue temperature in the porous heat transfer model is slightly lower than that in the Pennes heat transfer model. The possible reason is that there are pores in the porous model, and the pores are filled with blood flow; the blood flow will take away some heat. It can be seen from Table 4 that the error between the calculated tissue temperature by the porous heat transfer model and the experimental one is less, which verifies the correctness of the simulation model.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Properties**} & \multicolumn{3}{c}{**Value**} \\ \cline{2-4}  & **Lung Tissue (0)** & **Blood (b)** & **Tumor (0)** \\ \hline Relative permittivity; \(\varepsilon\), (\(\cdot\)) & 33 & 58.3 & 48.16 \\ Electric conductivity; \(\sigma\) (S/m) & 0.4 & 2.54 & 2.096 \\ Density; \(\rho\) (kg/m)\({}^{2}\) & 480 & 1058 & 1040 \\ Specific heat capacity; \(\sigma\) (\(\log\)/kg\({}^{\circ}\)C) & 2967 & 3960 & 3960 \\ Thermal conductivity; \(K\) (W/m\({}^{-}\)C) & 0.40 & 0.45 & 0.57 \\ \hline \hline \end{tabular}
\end{table}
Table 1: The dielectric and thermal properties of tissue, blood and tumor [21; 24].  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Applications**} & \multicolumn{3}{c}{**Value**} \\ \cline{2-4}  & **Dielectric** & **Catheter** & **Slot** \\ \hline Relative permittivity \(\varepsilon_{c}\)(\(\cdot\)) & 2.03 & 2.1 & 1 \\ Electric conductivity \(\sigma\)(S/m) & 0 & 0 & 0 \\ Relative permeability \(\mu\),(\(\cdot\)) & 1 & 1 & 1 \\ \hline \hline \end{tabular}
\end{table}
Table 2: The dielectric properties of a single-slot MW antenna [24].  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Applications**} & \multicolumn{3}{c}{**Maximum Temperature Reached by Lung Tissue (\({}^{\circ}\)C)**} \\ \cline{2-4}  & **Experimental Data [26]** & **Porous Model** & **Pennes Model** \\ \hline
8 min & 80.5 & 86.8 & 90.2 \\
10 min & 90.2 & 95.3 & 96.4 \\
11 min & 94.4 & 98.6 & 103.0 \\
12 min & 101.0 & 103.8 & 108.4 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Maximum temperature of lung tissue under different conditions.