Microwave device for vascular ablation

A method for ablation of a varicose vein, comprising the steps of:

• positioning a triaxial microwave catheter comprising an antenna within a varicose vein to be treated, said triaxial microwave catheter comprising i) a first conductor, ii) a tubular second conductor coaxially around the first conductor but insulated therefrom, iii) a tubular third conductor coaxially around the first and second conductors, and iv) a tuning mechanism having a locked state fixedly holding the third conductor against axial movement with respect to the first and second conductors and having a unlocked state allowing axial movement between the third conductor and the first and second conductors;
• wherein the first conductor extends beyond the second conductor into tissue, when a distal end of the probe is inserted into a body for microwave ablation, to promote microwave frequency current flow between the first and second conductors through the tissue;
• and wherein the second conductor may be adjusted by the tuning mechanism to extend beyond the third conductor into tissue when an end of the probe is inserted into the body for microwave ablation to provide improved tuning of the probe limiting power dissipated in the probe outside of exposed portions of the first and second conductors;
• delivering ablative power to the varicose vein.

A probe for ablation comprising:

• a first conductor;
• a second conductor coaxially around the first conductor but insulated therefrom;
• a third conductor coaxially around the first and second conductors;
• wherein the first conductor extends beyond the second conductor by a distance L2 and the second conductor extends beyond the third conductor by a distance L1 wherein L1 and L2 are odd multiples of a quarter wavelength of a microwave frequency received by the probe within tissue.