Comparative experiments on phantom and ex vivo liver tissue in microwave ablation

Abstract

Purpose: The aim of this study is to investigate the thermal field distribution of phantom and ex vivo liver tissue in microwave ablation. We intent to verify if the phantom can be used in future studies in lieu of actual tissue. Methods: This experiment was divided into two groups of phantom and ex vivo porcine liver tissue. 2450 MHz is set. The tests last up to 240 s in 60 W. The velocity of the circulating water pumps were adjusted to 40 rounds/min. Twenty-five copper-constantan thermocouples (TCs) were inserted at the specified position to record temperature data. Result: For the cooling water, the temperature field was non-symmetric distribution at the gap before (z > z < 0 mm) of two groups of experiments. At the part without cooling water (z > 0 mm), effective ablation areas were larger; near the microwave antenna, the temperature curves showed good consistency for both materials. Far away from the microwave antenna, the value difference increased between phantom and liver tissue. Moreover, the effect of cooling water in phantom is more obvious than it in liver tissue. The shapes of ablation areas from two groups are not same. Conclusion: The result of the present work implied that heating patterns of liver tissue and phantom are comparable. But the difference of temperature field between two kinds of materials cannot be ignored. In cases of using phantom to verify temperature field in lieu of actual tissue, the researchers should pay full attention to these difference points.