Microwave ablation probe

Abstract

A microwave ablation probe is disclosed. The microwave ablation probe includes an applicator arranged to apply microwave radiation to heat surrounding tissue; a feeding cable arranged to supply electromagnetic energy to the applicator; an antenna portion of an inner conductor of the feeding cable, the antenna portion extending distally from a distal end of an outer conductor of the feeding cable; and an overlapping portion of the inner conductor at least partly overlapping the antenna portion along the length of the antenna portion of the inner conductor and extending along a helical path around the antenna portion of the inner conductor.

1 . A microwave ablation probe, comprising:
 an applicator arranged to apply microwave radiation to heat surrounding tissue; and   a feeding cable arranged to supply electromagnetic energy to the applicator, wherein the feeding cable is formed from an inner conductor and an outer conductor, and wherein the applicator comprises:
 an antenna portion of the inner conductor, the antenna portion extending distally from a distal end of the outer conductor; and 
 an overlapping portion of the inner conductor at least partly overlapping the antenna portion along a length of the antenna portion of the inner conductor and extending along a helical path around the antenna portion of the inner conductor. 
   
     
     
         2 . The microwave ablation probe according to  claim 1 , wherein the applicator further comprises a dielectric insulator, at least part of the dielectric insulator being disposed between the antenna portion of the inner conductor and the overlapping portion of the inner conductor, the overlapping portion of the inner conductor extending around the dielectric insulator. 
     
     
         3 . The microwave ablation probe according to  claim 2 , wherein the dielectric insulator further comprises a hole through which the inner conductor passes to form a connection between the antenna portion of the inner conductor and the overlapping portion of the inner conductor extending around the dielectric insulator. 
     
     
         4 . The microwave ablation probe according to  claim 2 , wherein the dielectric insulator further comprises an outer surface having a recessed portion, the recessed portion arranged to receive the overlapping portion of the inner conductor. 
     
     
         5 . The microwave ablation probe according to  claim 1 , wherein a pitch of a helix formed by the overlapping portion of the inner conductor is greater than 0.05% of a wavelength of the microwave radiation emitted by the applicator measured in air. 
     
     
         6 . The microwave ablation probe according to  claim 1 , wherein the antenna portion of the inner conductor extends distally beyond the distal end of the outer conductor a distance of between 0.3% and 10% of a wavelength of the microwave radiation emitted by the applicator measured in air. 
     
     
         7 . The microwave ablation probe according to  claim 1 , wherein the overlapping portion of the inner conductor extends along the length of the antenna portion of the inner conductor a distance of between 0.3% and 20% of a wavelength of the microwave radiation emitted by the applicator measured in air. 
     
     
         8 . The microwave ablation probe according to  claim 1 , wherein the overlapping portion of the inner conductor is cooled by coolant flowing in a coolant flow path of the ablation probe. 
     
     
         9 . The microwave ablation probe according to  claim 1 , wherein the applicator further comprises a sleeve member, the sleeve member arranged to surround an overlapping antenna portion of the inner conductor to restrict the transfer of heat from the overlapping antenna portion of the inner conductor. 
     
     
         10 . The microwave ablation probe according to  claim 9 , wherein the applicator comprises a dielectric insulator, and wherein the sleeve member is spaced apart from part of an outer surface of the dielectric insulator to form a coolant channel therebetween. 
     
     
         11 . The microwave ablation probe according to  claim 9 , wherein the applicator comprises a dielectric insulator, the dielectric insulator having one or more channels in a surface of the dielectric insulator arranged to form a coolant flow path. 
     
     
         12 . The microwave ablation probe according to  claim 2 , wherein the inner conductor, the outer conductor, and a dielectric material of the feeding cable extend into a body of dielectric insulator such that the dielectric insulator surrounds a distal portion of the feeding cable.