Theoretical Evaluation of the Effectiveness of Radiofrequency and Microwave Ablation Methods for Liver Neoplasms

The main advantages of radiofrequency ablation are its availability, reproducibility and low complication rate. However, physical peculiarities of this method, namely a significant drop in the conductivity of tissue heated to a hundred degrees, do not allow its use for tumors larger than 3-4 centimeters, so other methods are used for areas of larger diameter, the most commonly used and close in mechanism of action of which is microwave ablation. The development of new methods of temperature control based on the measurement of radiofrequency signals can expand the field of application of radiofrequency ablation. In this work we have developed several models simulating the effect of radiofrequency and microwave currents on liver tumor tissues. To quantitatively assess the effectiveness of ablation methods for liver neoplasms, we used a mathematical model based on the joint solution of the heat conduction equations, taking into account the processes of blood flow, Poisson and Arrhenius. The results obtained allow us to state that increasing the area of electrode-tissue contact for the case of radiofrequency ablation theoretically allows to achieve comparable volumes of heated and destroyed tissue with microwave ablation. Increasing the frequency of the applied signal, although it allows increasing the volume of damaged and heated tissue, also increases the maximum temperature of its heating, which forces to reduce the voltage at the input electrode to avoid tissue drying.