Radiofrequency ablation (RFA) has been used successfully in the treatment of liver tumors. However, current RFA procedures are less effective against tumors that are large. The purpose of this study was to investigate internally cooled multiple-electrode technique with radio-frequency ablation (RFA) which technique could provide larger thermal lesion by using computer simulation and to determine optimal RF electrode spacing based on coagulation necrosis zone volume. Multiple electrically independent electrodes have been powering up by switching to the next electrode at a predetermined time interval of certain time period. As to computer models, the mathematical equations use Laplace equation of electric field calculation, and Bio-heat transfer equation of calculation temperature field. Numerical methods will consider Gauss-Seidel iteration to obtain 3-D finite difference solutions of a set of partial differential equations for a simple three-dimensional cubic geometry model. Maximum tissue temperature (T_(max)) is used as a critical index for reaching thermal lesion formation during RFA and threshold temperature (T_(thresh)) is used to estimate coagulation zone volume. Cylindrical RF cool-tip electrode is internally cooled at constant water temperature. Results showed several clover-shaped resultant coagulation necrosis and enlarged thermal lesions which were consistent with experimental results.
淡江理工學刊=Journal of Applied Science and Engineering, 18(3), pp.275-288