According to our simulation investigation, there still exists some RFA lesions that are unachievable by single ablation. In principle, for all RFA devices, the higher degree of freedom (DOF), the better conformality. However, higher DOF also means higher operation/control complexity and hence higher expense. Thus, a trade-off between conformality and operation complexity finally results in current design that is capable of conformally ablating various target tissues through simple operations. Furthermore, several supplementary strategies can be adopted for improving conformality between the target tissues and RFA lesions. For instance, sequential combinations of axial, radial and circumferential morphing (motions of cannula, stylet and rotation of electrode respectively) can be used to conform to target tissues (e.g., after the first ablation and withdrawal of sub-electrode, the main electrode can rotate and the sub-electrodes can be expanded for another ablation. Cylindrical coordinate system of our electrode refers to Figure 13). Last but not least, appropriate preoperative planning by either computers or physicians is also important to minimize the unnecessarily excessive ablations.\cite{Patriciu_2005,Koethe_2013,Abdullah_2014,Abdullah_2013}