METHODS AND DEVICES FOR FLUID ENHANCED MICROWAVE ABLATION THERAPY

• US 20140276743A1
• Filed: 03/15/2013
• Published: 09/18/2014
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Thermedical, Inc.
• Original Assignee: Thermedical, Inc.
• Inventors: Curley, Michael G.
• Granted Patent: US 9,033,972 B2
• Time in Patent Office: Days
• US Class Current: 606/33
• CPC Class Codes: A61B 18/1815 using microwaves
• CPC Class Codes: A61B 2018/00011 with fluids
• CPC Class Codes: A61B 2018/00017 with gas
• CPC Class Codes: A61B 2018/00029 open
• CPC Class Codes: A61B 2018/00351 Heart
• CPC Class Codes: A61B 2018/00529 Liver
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00642 with feedback, i.e. closed loop control
• CPC Class Codes: A61B 2018/0066 without feedback, i.e. open loop control
• CPC Class Codes: A61B 2018/00702 Power or energy
• CPC Class Codes: A61B 2018/00714 Temperature
• CPC Class Codes: A61B 2018/00821 measured by a thermocouple
• CPC Class Codes: A61B 2018/00898 Alarms or notifications created in response to an abnormal condition
• CPC Class Codes: A61B 2018/00994 combining two or more different kinds of non-mechanical energy or combining one or more non-mechanical energies with ultrasound
• CPC Class Codes: A61B 2018/044 the surgical action being effected by a circulating hot fluid

Abstract

Devices and methods for fluid enhanced ablation therapy using microwave antennas are described herein that provide improved heat transfer into a target volume of tissue and improved antenna cooling compared to prior art designs. In one embodiment, fluid can be introduced into a target volume of tissue along with the delivery of therapeutic energy from a microwave antenna positioned within the target volume of tissue. The fluid can become heated by cooling the microwave antenna and, if additional heating of the fluid is desired, a heating element disposed within the microwave antenna can supplementally heat the fluid prior to introduction into the target volume of tissue.

Claims

1. A microwave ablation device, comprising:

an elongate body having

an inner conducting element surrounded by a dielectric insulator,

an outer conducting element coaxially disposed around the dielectric insulator and defining an outer wall, and

a plurality of separate fluid channels extending through the dielectric insulator parallel to a longitudinal axis of the microwave antenna, each fluid channel including at least one opening to allow fluid to flow into tissue surrounding the elongate body;

wherein the inner and outer conducting elements are configured to deliver microwave energy to tissue surrounding the elongate body and wherein the at least one opening extends through the dielectric insulator and the outer conducting element.

2. The device of claim 1, wherein the at least one opening is positioned at a location proximal to a distal end of the inner conductive element.

3. The device of claim 1, wherein the at least one opening comprises a plurality of openings spaced along a longitudinal axis of each of the plurality of fluid channels.

4. The device of claim 1, wherein the at least one opening comprises a plurality of openings spaced circumferentially around a longitudinal axis of each of the plurality of fluid channels.

6. The device of claim 1, wherein the microwave antenna has a cylindrical shape, and wherein the inner conducting element, dielectric insulator, and outer conducting element are coaxially aligned.

7. The device of claim 1, wherein each of the plurality of fluid channels, includes a heating element disposed therein, the heating element being positioned proximal to the at least one opening and configured to heat fluid flowing through the channel.

8. The device of claim 1, further comprising a shield disposed around and coaxially aligned with the outer conducting element.

5. (canceled)

9. (canceled)

10. (canceled)

11. (canceled)

12. (canceled)

13. An ablation device, comprising:

a microwave antenna having

a hollow outer conducting element,

a coaxial inner conducting element extending through the outer conducting element,

a fluid channel positioned between the outer and inner conducting elements,

an inner lumen extending through the inner conducting element,

a return channel in fluid communication with the inner lumen and isolated from the fluid channel, and

at least one outlet port formed in the outer conducting element at a distal end of the antenna and in fluid communication with the fluid channel, the at least one outlet port being configured to deliver fluid flowing through the fluid channel into tissue surrounding the microwave antenna; and

wherein the inner lumen is configured to receive a cryogenic gas and vent the cryogenic gas into the return channel such that the cryogenic gas does not enter the fluid channel.

14. The device of claim 13, further comprising at least one heating element disposed in the fluid channel and configured to heat fluid flowing through the channel.

21. The device of claim 13, wherein the return channel has an annular shape.

15-20. -20. (canceled)