US 6,230,060 B1Granted

Single integrated structural unit for catheter incorporating a microwave antenna

OwnerDaniel D. Mawhinneyinventor

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Abstract

The catheter constitutes a single integrated structural unit comprising a first tubular balloon-supporting structure having a given outer diameter and a second structure inserted therein comprising an antenna and a coaxial cable for energizing the antenna. This permits both the antenna and the longitudinal cable to be wider, without any increase in the given outer diameter, than would be the case if the catheter were a prior-art non-integrated structure in which the tubular first structure and the second structure are separate detached units and, therefore, require clearance therebetween to permit insertion. In both basic and preferred embodiments, the single integrated structural is achieved by an electrically conductive shield attached by spacers to an outer conductor of the coaxial cable. In the basic embodiment, the shield is spaced from both the outer cable conductor and first structure to form inner and outer channels for exiting and entering the circulating balloon-inflating liquid. In the preferred embodiment, the shield is bonded to the inner surface of the first structure to form the entering channel, while the exiting channel is formed by the interior of a tubular inner cable conductor which may also house a thin tube for air inflating a Foley balloon. The inner channels of both embodiments include a ¼ wavelength choke structure at the distal end of the coaxial cable. A modification divides the circumference of the channels into separate angular sectors for independently circulating inflating liquid to any of a plural number of differently-sized balloons.

In a urethral balloon catheter incorporating an antenna suitable for use in therapeutically heating a diseased prostate of a male patient with energy radiated from said antenna, wherein said urethral catheter comprises (1) a tubular catheter first structure longitudinally extending from a proximate end thereof to a distal end thereof that includes an attached inflatable balloon situated near the distal end thereof together with input and output channels for use in circulating a balloon-inflating fluid, said tubular catheter first structure having a given outer diameter sufficiently small to permit it to be inserted inside of the urethra of said male patient with said balloon in its deflated state, and (2) a second structure inserted within said tubular catheter first structure that comprises said antenna situated toward said distal end of said tubular catheter first structure and a longitudinal coaxial cable comprising an inner conductor having a first given diameter, an outer conductor having a second given diameter and a dielectric having a given dielectric constant situated between said inner and outer conductors, said coaxial cable extending from the proximate end of said tubular catheter first structure to said antenna for use in energizing said antenna;

the improvement wherein:
said tubular catheter first structure and said second structure of said urethral balloon catheter are constructed to comprise a single integrated structural unit that includes interface structure comprising a longitudinal electrically conductive shield physically attached to both said outer conductor and an inner surface of said tubular catheter first structure;
whereby both said antenna and said longitudinal cable may be wider, without any increase in said given outer diameter, than would be the case if said urethral balloon catheter were a non-integrated structure in which said tubular catheter first structure and said second structure constitute separate units that are detached from one another and, therefore, would require clearance between the second structure and the tubular catheter first structure sufficient for a non-permanent insertion of the second structure within the tubular catheter first structure.

Abstract

Claims18