Abstract: The subject matter described relates to a coaxial ablation probe and method and system for real time monitoring of ablation progress for percutaneous ablation. The probe includes an anode. The probe further includes a size and shape adjustable cathode cage surrounding the anode, the cathode cage includes a plurality of struts. The anode extends coaxially with respect to the struts that form the cathode cage. The cathode cage defines the treatment volume. Probe insertion and ablation progress will be monitored by a magnetic resonance imaging system.