Morphologic Characterization of RFA Lesions

By means of finite element analysis, the mechanism of on-demand conformal RFA is further investigated. Since the morphologic appearance of RFA lesion mainly contains size (or ablated volume) and shape, these two aspects are considered in our performance evaluation. As illustrated in Figure 10A, the heat will accumulate in the surrounding tissues and thus cause overheat of tissues, which prevent further enlargement of RFA lesion. As further revealed in Figure 10B, rapid impedance increase occurs with the slowdown of the increasing rate of ablated volume. The ablated area starts from the tip of the electrode and finally forms a shape that is similar to the shape of electrode (insets in Figure 10B and Figure 11). Owing to such an effect, we are able to adjust the expanded length of the electrode to adapt diverse shapes of RFA lesion and achieve different volumes of RFA lesion, Figure 10C.