An energy delivery system for performing tissue ablation at the distal end of an Electromagnetic Navigation Bronchoscopy (ENB) instrument. The system is insertable through an instrument channel of a steerable instrument cord in an ENB instrument, and comprise a coaxial cable with a radiating tip portion. The tip portion comprises a first conductive element electrically connected to the coaxial cable's inner conductor and a second conductive element electrically isolated from the inner conductor. The conductive elements are arranged to act as: an active electrode and a return electrode for delivering the RF energy into tissue surrounding the radiating tip portion, and an antenna for radiating the microwave energy as a localized microwave field. The system may be arranged to delivery energy according to a predetermined profile comprising interleaving periods of RF and microwave energy or a combination thereof, or a dynamic profile based on detected tissue impedance.
