High-strength microwave antenna assemblies

• US 6,878,147 B2
• Filed: 11/02/2001
• Issued: 04/12/2005
• Est. Priority Date: 11/02/2001
• Status: Expired due to Term

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Vivant Medical, Inc. (Johnson Controls International plc)
• Inventors: Prakash, Mani, Kim, Steven, Rossetto, Francesca, Su, Ted, Lee, Anthony, Glassman, Jonathan
• Primary Examiner(s): Flanagan, Beverly M.
• Assistant Examiner(s): Vrettakos, Peter J
• Application Number:
  US10/052,848
• Publication Number:
  US 20030088242A1
• Time in Patent Office: 1,257 Days
• Field of Search: 606/1, 606 27- 50, 607/101, 607/156
• 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 2018/00077 high, i.e. electrically conducting
• CPC Class Codes: A61B 2018/00083 low, i.e. electrically insulating
• CPC Class Codes: A61B 2018/00136 with polymer
• CPC Class Codes: A61B 2018/00142 lubricating
• CPC Class Codes: A61B 2018/00178 Electrical connectors
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/1823 Generators therefor
• CPC Class Codes: A61B 2018/1838 Dipole antennas
• CPC Class Codes: A61B 2018/1853 Monopole antennas
• CPC Class Codes: A61B 2018/1869 with an instrument interstitially inserted into the body, e.g. needles
• CPC Class Codes: A61B 2018/1892 Details of electrical isolations of the antenna
• CPC Class Codes: Y10T 29/49005 Acoustic transducer
• CPC Class Codes: Y10T 29/49007 Indicating transducer
• CPC Class Codes: Y10T 29/49016 Antenna or wave energy "plumbing" making
• CPC Class Codes: Y10T 29/49018 with other electrical component

Abstract

Various high-strength microwave antenna assemblies are described herein. The microwave antenna has a radiating portion connected by a feedline to a power generating source, e.g., a generator. The antenna is a dipole antenna with the distal end of the radiating portion being tapered and terminating at a tip to allow for direct insertion into tissue. Antenna rigidity comes from placing distal and proximal radiating portions in a pre-stressed state, assembling them via threaded or overlapping joints, or fixedly attaching an inner conductor to the distal portion. The inner conductor is affixed to the distal portion by, e.g., welding, brazing, soldering, or by adhesives. A junction member made from a hard dielectric material, e.g., ceramic, can be placed between the two portions and can have uniform or non-uniform shapes to accommodate varying antenna designs. Electrical chokes may also be used to contain returning currents to the distal end of the antenna.

Claims

1. A microwave antenna assembly for applying microwave energy therapy comprising:

a proximal portion having an inner conductor and an outer conductor, each extending therethrough, the inner conductor disposed within the outer conductor; and

a distal portion attached to the proximal portion such that this inner conductor extends at least partially therein,

wherein the proximal and distal portions are configured to mate together such that the proximal and distal portions are fixedly positioned relative to one another by a mechanically engaging joint adapted to electrically insulate between the distal portion and the proximal portion while coupling the distal portion to the proximal portion such that the mechanically engaging joint is adapted to be in a pro-stressed condition, and wherein both the proximal and distal portions are further adapted to be penetrated directly into tissue.

2. The microwave antenna assembly of claim 1 further comprising a junction member disposed between the proximal and distal portions.

3. The microwave antenna assembly of claim 2 wherein the junction member comprises a dielectric material.

4. The microwave antenna assembly of claim 1 wherein the distal portion has a tapered distal end.

5. The microwave antenna assembly of claim 1 wherein the proximal and distal portions are adapted to radiate upon transmission of radiation trough the antenna assembly.

6. The microwave antenna assembly of claim 5 wherein the proximal and distal portions have a length which is proportional to an effective wavelength of the radiation transmitted by the antenna assembly.

7. The microwave antenna assembly of claim 1 wherein the distal portion compilses a metal or dielectric material.

8. The microwave antenna assembly of claim 1 wherein to distal portion is attached tote inner conductor by a method selected from the group consisting of welding, brazing, soldering, and adhesives.

9. The microwave antenna assembly of claim 1 further comprising a dielectric coating disposed at least partially over the antenna assembly.

10. The microwave antenna assembly of claim 9 wherein the dielectric coating comprises a ceramic.

11. The microwave antenna assembly of claim 1 further comprising a sealant coating disposed at least partially over the antenna assembly.

12. The microwave antenna assembly of claim 1 further comprising a conductive layer which is located proximally of the distal portion and is in electrical communication with the outer conductor.

13. The microwave antenna assembly of claim 1 further comprising a dielectric material disposed between the proximal and distal portions.

14. The microwave antenna assembly of claim 1 wherein the distal portion comprises at least a first section which interfits with a second suction in a mated joint such that the first and the second section forms an integral distal portion.

15. The microwave antenna assembly of claim 1 wherein the mechanically engaging joint comprises a threaded interface.

16. The microwave antenna assembly of claim 15 wherein the threaded interface comprises a junction member having a threaded distal and proximal section.

17. The microwave antenna assembly of claim 1 wherein the mechanically engaging joint comprises an interference-fit between each of the portions.

18. The microWave antenna assembly of claim 1 wherein the mechanically engaging joint comprises a plurality of pins extending between the portions.

19. The microwave antenna assembly of claim 1 wherein the mechanically engaging joint comprises a plurality of projections radially disposed about the proximal or distal portion.

20. A kit for applying microwave energy therapy comprising:

a microwave antenna assembly as described in claim 1; and

a power source for supplying power to the microwave antenna assembly.

21. The kit of claim 20 wherein the power source comprises a generator.

47. The microwave antenna assembly of claim 1 wherein the mechanically engaging joint comprises an overlapping joint between each of the portions.

48. The microwave antenna assembly of claim 47 wherein the overlapping joint comprises a plurality of pins extending between the proximal and distal portions, each of the proximal and distal portions defining a plurality of corresponding holes for respectively receiving the plurality of pins.

49. The microwave antenna assembly of claim 47 wherein the distal portion comprises a plurality of projections radially disposed on an outer surface of the distal portion, and wherein the proximal portion comprises a plurality of depressions radially defined in an inner surface of the proximal portion, the plurality of projections being configured to intimately mate with the plurality of depressions such that the distal portion is held fixed relative to the proximal portion.

50. The microwave antenna assembly of claim 49 wherein the plurality of projections are configured to retract at least partially into the outer surface during insertion of the distal portion into the proximal portion.

51. The microwave antenna assembly of claim 49 wherein the proximal portion further defines a plurality of channels extending radially from the plurality of depressions defined in the inner surface to an outer surface of the proximal portion.

22. A microwave antenna assembly for applying microwave energy therapy comprising:

a proximal portion having an inner conductor and an outer conductor, each extending therethrough, the inner conductor disposed within the outer oonductor;

a junction member having a longitudinal thickness and disposed distally of the proximal portion such tat the inner conductor extends therethrough;

a distal portion disposed distally of the junction member such tat the inner conductor extends at least partially therein, and

wherein the distal portion and proximal portion are adapted to be penetrated directly into tissue and apply a compressive force on at least a portion of the junction member, which is further adapted to electrically insulate between the distal portion and the proximal portion.

23. The microwave antenna assembly of claim 22 wherein the proximal portion has a length corresponding to a distance of one-quarter wavelength of radiation transmittable through the antenna assembly.

24. The microwave antenna assembly of claim 22 wherein the proximal portion is adapted to radiate along the length upon transmission of the radiation.

25. The microwave antenna assembly of claim 22 wherein the junction member comprises a dielectric material.

26. The microwave antenna assembly of claim 22 wherein the junction member has a radial thickness which is uniform about a longitudinal axis as defined by the junction member.

27. The microwave antenna assembly of claim 22 wherein the junction member has a radial thickness which is non-uniform about a longitudinal axis as defined by the junction member.

28. The microwave antenna assembly of claim 27 wherein the junction member is stepped such that the member comprises at least two different radial thicknesses.

29. The microwave antenna assembly of claim 22 wherein the distal portion has a tapered distal end.

30. The microwave antenna assembly of claim 22 wherein the distal portion has an actual length defined along an outer surface of the distal portion such that a cumulative distance of the actual length and the thickness of the juitetion member corresponds to a distance of one-quarter wavelength of radiation transmittable through the antenna assembly.

31. The microwave antenna assembly of claim 22 wherein the distal portion comprises a metal.

32. The microwave antenna assembly of claim 22 wherein the inner conductor extends through the distal portion.

33. The microwave antenna assembly of claim 22 wherein the distal portion defines a channel extending from the inner conductor disposed within the distal portion to an outer surface of the distal portion.

34. The microwave antenna assembly of claim 22 wherein the distal portion is attached to the inner conductor by a method selected from the group consisting of welding, brazing, soldering, and adhesives.

35. The microwave antenna assembly of claim 22 wherein when the antenna is under a state of zero external stress, the inner conductor is in a state of tension and is attached to the distal portion such that the distal portion applies the compressive force against the junction member.

36. The microwave antenna assembly of claim 22 further comprising a dielectric coating disposed at least partially over the antenna assembly.

37. The microwave antenna assembly of claim 22 further comprising a sealant coating disposed at least partially over the antenna assembly.

38. The microwave antenna assembly of claim 37 wherein the sealant coating comprises a thermoplastic polymer.

39. The microwave antenna assembly of claim 22 further comprising a conductive layer which is located proximally of the distal portion and is in electrical communication with the outer conductor.

40. The microwave antenna assembly of claim 39 wherein the conductive layer is selected from the group consisting of conductive coatings, nietaflic foil, and metal tubing.

41. The microwave antenna assembly of claim 39 further comprising a first dielectric layer disposed at least partially between the conducttve layer and the proximal portion.

42. The microwave antenna assembly of claim 41 further comprising a second dielectric layer disposed at least partially about the conductive layer.

43. The microwave antenna assembly of claim 39 wherein the conductive layer is disposed at least partially about a coaxial feedline connecting the antenna assembly to a generator.

44. The microwave antenna assembly of claim 43 further comprising a dielectric layer disposed between the conductive layer and the proximal portion.

45. The microwave antenna assembly of claim 22 wherein the distal portion has an actual length defined along an outer surface of the distal portion such that the actual length corresponds to a distance of one-half wavelength of radiation transmittable through the antenna assembly.

46. The microwave antenna assembly of claim 45 wherein the inner conductor is in a state of tension and is attached to the distal portion such that the distal portion applies the compressive foive against the junction member.