Air-core microwave ablation antennas

Abstract

A method and device delivers microwave power to an antenna through a coaxial cable utilizing air or other gases as its dielectric core. The cable includes supports made of low-loss materials to keep the inner conductor centered in the cable, and defining spaces therebetween for the air or gas. Channels in the supports allow the air or gas to circulate in the cable. The gas may be chilled or cooled to provide an addition level of heat dissipation. The device enables delivery of large amounts of power to tissue without undue heating of the feed cable or peripheral tissues, and without increasing the diameter of the feeding cable or antenna, keeping the antenna safe for percutaneous use.

1 . A device for delivery of microwave power to an antenna, comprising:
 a coaxial cable having air or other gas as the dielectric core; and   discrete supports integrated into the cable.   
     
     
         2 . The device of  claim 1 , further comprising flow channels in each support. 
     
     
         3 . A device for combined delivery of microwave power to an antenna and cooling of the device, comprising:
 a co-axial cable having air or other gas as the dielectric core; and   discrete supports integrated into the cable.   
     
     
         4 . The device of  claim 3 , further comprising flow channels in supports. 
     
     
         5 . The device of  claim 3 , further comprising a hollow tube center conductor. 
     
     
         6 . A method for delivery of microwave power to an antenna, comprising the steps of:
 defining spaces in a co-axial cable attached to the antenna;   circulating gas between the spaces in the co-axial cable; and   supplying power to the co-axial cable.   
     
     
         7 . The method of  claim 6  wherein the co-axial cable has a hollow tube center conductor.