A method and apparatus are disclosed for treating tissue, including an intra-operative mapping of a probe ablation zone. The method uses a system that maps the proximal and distal margins of the probe ablation zone using tools that are used to access the ablation target. In some embodiments, the tools comprise an introducer assembly, including a cannula and a stylet, and a bone drill. The tools have features or markings that cooperate to indicate which probe to use to achieve the desired ablation. The method further facilitates planning probe placement for delivering energy to treat (ablate) a desired ablation volume of a target tissue by using a system that maps both the target tissue and possible probe ablation zones.
