An RF ablation system (10) includes an electrode element (12) of elongate form and a cathode pad (14). A control unit (40) includes a processing unit (42), a power unit (44) and, optionally, a temperature sensor (46) and/or an impedance sensor (48). The control unit (40) in one embodiment carries out RF ablation in at least two phases, the first phase at a higher energy level and a second phase, after at least partial retraction of the anode element (12), at a second lower phase in order to close any remaining lumen within a blood clot formed within the vessel (18) during the first phase. Other embodiments provide for sensing retraction of the anode terminal (12) and effecting RF ablation during and/or after the retraction process in order to create a more effective occlusion barrier.
