A method for implementing a microwave ablation waveguide, that includes selecting a lumen adapted to convey a fluid and formed from living biological tissue, introducing an elongate inner conductor into the lumen, positioning at least a portion of the elongate inner conductor within the lumen such that a longitudinal axis of the elongate inner conductor is positioned substantially parallel to and at a desired distance from a longitudinal axis of the lumen and proximate an anatomical feature of interest, and transferring microwave energy along the elongate inner conductor such that the lumen shields the inner conductor and allows a pre-determined amount of microwave energy to propagate through the anatomical feature of interest.
