Ex vivo validation of microwave thermal ablation simulation using different flow coefficients in the porcine liver.

The purpose of the study was to validate the simulation model for a microwave thermal ablation in ex vivo liver tissue. The study aims to show that heat transfer due to the flow of tissue water during ablation in ex vivo tissue is not negligible. Ablation experiments were performed in ex vivo porcine liver with microwave powers of 60 W to 100 W. During the procedure, the temperature was recorded in the liver sample at different distances to the applicator using a fiber-optic thermometer. The position of the probes was identified by CT imaging and transferred to the simulation. The simulation of the heat distribution in the liver tissue was carried out with the software CST Studio Suite. The results of the simulation with different flow coefficients were compared with the results of the ablation experiments using the Bland-Altman analysis. The analysis showed that the flow coefficient of 90,000 W/(K*m3) can be considered as the most suitable value for clinically used powers. The presented simulation model can be used to calculate the temperature distribution for microwave ablation in ex vivo liver tissue.