Microwave apparatus for controlled tissue ablation

• US 20070219548A1
• Filed: 03/16/2006
• Published: 09/20/2007
• Est. Priority Date: 03/16/2006
• Status: Active Grant

• Current Assignee: Coral Sand Beach, LLC
• Original Assignee: Meridian Medical Systems LLC
• Inventors: Carr, Kenneth
• Granted Patent: US 7,699,841 B2
• Time in Patent Office: Days
• US Class Current: 606/33
• CPC Class Codes: A61B 18/18 by applying electromagnetic radiation, e.g. microwaves radiation therapy A61N5/00
• CPC Class Codes: A61B 18/1815 using microwaves
• CPC Class Codes: A61B 2018/00351 Heart
• CPC Class Codes: A61B 2018/183 characterised by the type of antenna

Abstract

Apparatus for controlled tissue ablation includes an elongated relatively flexible antenna with a first, strip-like, conductor having opposite faces and proximal and distal ends, a dielectric spacer covering one face of the first conductor, and a second, serpentine, conductor composed of a series of similar segments positioned flush against the spacer and being coextensive lengthwise with the first conductor. The second conductor has a distal end connected to the distal end of the first conductor and a proximal end. An electrically insulating enclosure surrounds the conductors. The proximal ends of the first and second conductors may be connected via a coaxial cable to a remote microwave transmitter/receiver unit.

Claims

1. Apparatus for tissue ablation, said apparatus comprising

an elongated relatively flexible antenna catheter having opposite faces and including

a first, strip-like, conductor having opposite faces and proximal and distal ends,

an electrically insulating spacer covering one face of the first conductor, and

a second, serpentine, conductor composed of a series of similar segments positioned flush against said spacer and being coextensive lengthwise with the first conductor, said second conductor having a distal end connected to the distal end of the first conductor and a proximal end, and

an electrically insulating enclosure surrounding the conductors.

2. The apparatus defined in claim 1 wherein the first and second conductors each comprise an etched or printed conductor.

3. The apparatus defined in claim 1 wherein

the first conductor is a rectangular strip having opposite sides, and

said segments of the second conductor overhang the opposite sides of the first conductor.

4. The apparatus defined in claim 1 wherein the spacer is of a low dielectric material.

5. The apparatus defined in claim 1 and further including a coaxial cable having a grounded inner conductor connected to the proximal end of the first conductor, and an outer conductor connected to the proximal end of the second conductor.

6. The apparatus defined in claim 1 wherein the enclosure comprises a flexible envelope.

7. The apparatus defined in claim 1 wherein the enclosure comprises a body of low dielectric material adjacent one face of the catheter which directs an antenna pattern of the catheter away from the other face of the catheter.

8. The apparatus defined in claim 7 wherein the enclosure comprises

a housing of a low dielectric material and defining a recess shaped and arranged to receive the conductors so that the second conductor faces an entrance into the recess, and

a low dielectric cover covering said entrance.

9. The apparatus defined in claim 8 wherein the housing is of silicone or aerated PTFE.

10. The apparatus defined in claim 1 and further including

a microwave transmitter/receiver unit, and

a coaxial cable including an inner conductor having one end connected to the proximal end of the first conductor and an opposite end connected to said unit and an outer conductor having one end connected to the proximal end of the second conductor and an opposite end connected to said unit.

11. The apparatus defined in claim 1 wherein said antenna catheter has an antenna length in the range of 4 to 6 centimeters.

12. The apparatus defined in claim 1 and further including

a microwave transmitter, and

a coaxial cable connected between said transmitter and said antenna catheter.

13. The apparatus defined in claim 12 wherein

said transmitter transmits at a selected frequency in the range of 915 to 2450 MHz, and

the antenna catheter is substantially matched to said selected frequency.

14. The apparatus defined in claim 1 and further including a microwave receiver having a center frequency, and

a coaxial cable connected between the receiver and the antenna catheter.

15. The apparatus defined in claim 14 wherein the antenna catheter is substantially matched to said center frequency.

16. The apparatus defined in claim 1 and further including

a microwave transmitter which transmits at a first frequency;

a microwave receiver which has a selected center frequency substantially greater than said first frequency, and

a coaxial cable connecting the antenna catheter to the transmitter and receiver, said antenna catheter providing a good impedance match at both the first frequency and the center frequency.

17. Apparatus for tissue ablation, said apparatus comprising

an elongated relatively flexible antenna catheter, said antenna catheter having opposite faces and including

a serpentine conductor composed of a series of substantially similar sinuous segments and having proximal and distal ends and a longitudinal axis extending between said ends;

a substantially straight conductor having opposite first and second ends and a longitudinal axis extending therebetween, said conductors being spaced opposite one another with their axes in parallelism so as to provide an insulating gap between said of the conductors, and

a electrical connection between the distal ends of the conductors, and

a cable including a first conductive path connected to the proximal end of the serpentine conductor and a second conductive path connected to the proximal and of the straight conductor.

18. The apparatus defined in claim 17 and further including a dielectric spacer filling the gap between the serpentine and straight conductors.

19. The apparatus defined in claim 17 wherein said conductors each comprises an etched or printed conductor.

20. The apparatus defined in claim 19 wherein

the straight conductor is a substantially rectangular strip having opposite sides, and

said segments of the serpentine conductor overhang the opposites sides of the said strip.

21. The apparatus defined in claim 17 and further including a dielectric cover member insulating said conductors from the outside.