Numerical Study of the Influence of Water Evaporation on Radiofrequency Ablation

Radiofrequency (RF) ablation is one of the promising technologies of tumor therapy due to its minimal invasiveness and other advantages. The high frequency alternating electrical current makes movement of the intracellular ions, results in frictional heat inside the tumor tissue and local temperature rising. Temperature of the tissue near the RF electrode increases much faster than the distant part. When it reaches the vapor (boiling) point, excessive evaporation takes place and increases electrical impedance between the electrode and the targeted tissue. This has been a major obstacle for its application. Coolants such as water circulating in the electrodes has been proposed, but as the coolants are only effective on the electrode wall, quick evaporation and correspondent carbonization still exists.