Thermal ablation system

• US 6,328,735 B1
• Filed: 10/30/1998
• Issued: 12/11/2001
• Est. Priority Date: 10/30/1998
• Status: Expired due to Term

• Current Assignee: Thermedical, Inc.
• Original Assignee: E.P. Ltd.
• Inventors: Hamilton, Patrick S., Curley, Michael G.
• Primary Examiner(s): COHEN, LEE S
• Application Number:
  US09/183,461
• Time in Patent Office: 1,138 Days
• Field of Search: 606/41, 606/14, 606/15, 607/99, 607/105, 607/113
• US Class Current: 606/41
• CPC Class Codes: A61B 18/04 by heating by applying electromagnetic radiation A61B18/18; hyperthermia using electric or magnetic fields, radiation or ultrasound A61N
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 18/18 by applying electromagnetic radiation, e.g. microwaves radiation therapy A61N5/00
• CPC Class Codes: A61B 2018/046 in liquid form
• CPC Class Codes: A61B 2218/002 Irrigation

Abstract

A method and system for therapeutically treating a selected volume of tissue with a heated liquid. A therapeutic device, such as a catheter, is coupled to a source of liquid is heated to therapeutic temperatures by a heating mechanism. The device imparts thermal energy into the tissue while simultaneously injecting the heated liquid into the tissue. In a preferred embodiment, the device includes at least one electrode for conducting a radio-frequency current through the tissue in conjunction with the infusion of heated saline solution to selectively destroy the tissue.

Claims

1. A system for the therapeutic treatment of a volume of tissue, said system comprising

an energy source;

an emitter for contacting the tissue and thereby imparting energy from the source to the tissue to raise the temperature of the tissue;

a source of liquid which can be raised to a therapeutic temperature;

a chamber forming a passage fluidly coupled to the source of liquid and the emitter, the passage having a proximal end and a distal end proximate the emitter;

means for moving the liquid from the proximal end to the distal end;

means for heating the liquid within the passage from a first temperature below the therapeutic temperature to a second temperature at least as high as the therapeutic temperature such that the liquid does not reach the therapeutic temperature prior to being proximate the distal end; and

means for injecting the heated liquid into the tissue proximate to the emitter whereby the temperature of the volume of tissue is raised to a therapeutic level.

2. The system of claim 1 wherein

the energy source is a radio frequency generator; and

the emitter is an electrode connected to the source.

3. The system of claim 2 including a second emitter for contacting the tissue, said second emitter being a second electrode connected to the source whereby a current from the generator flows through the tissue between the electrodes.

4. The system of claim 3 wherein the emitters are metal salt electrodes.

5. The system of claim 3 wherein the emitters are silver/silver chloride electrodes.

6. The system of claim 1 wherein the energy source is lightwave generator and the emitter emits lightwave electromagnetic energy.

7. The system of claim 1 wherein the means for heating the liquid includes an electrically resistive element to conduct heat into the liquid.

8. The system of claim 1 wherein the means for heating the liquid includes means for conducting a radio frequency current through the liquid.

9. The system of claim 8, wherein the chamber has an axis and the heating means includes a pair of spaced apart electrodes disposed in the chamber at substantially the same axial position.

10. A system for the therapeutic treatment of a volume of tissue, said system comprising

an energy source;

a source of liquid which can be raised to a therapeutic temperature;

an elongated catheter having distal and proximal ends, the catheter including

an emitter coupled to the energy source and disposed at the distal end for contacting the tissue and thereby imparting energy from the source to the tissue to raise the temperature of the tissue,

a body forming a channel fluidly coupled to the source of liquid and the emitter, the channel having a proximal end and a distal end proximate the emitter,

means for transporting heated liquid in a substantially continuous flow through the channel from the proximal to the distal end and into the tissue proximate to the emitter whereby the temperature of the volume of tissue is raised to a therapeutic level, and

means for heating the liquid within the channel from a first temperature below the therapeutic temperature to a second temperature at least as high as the therapeutic temperature such that the liquid does not reach the therapeutic temperature prior to being proximate the distal end.

11. The system of claim 10, wherein the heating means are disposed proximate the distal end.

15. The method of claim 10 wherein the radio frequency current is conducted into the tissue through electrodes.

16. The method of claim 11 wherein the electrodes are formed from a metal salt.

17. The method of claim 11 wherein the electrodes are formed from silver/silver chloride.

12. A system for the therapeutic treatment of a volume of tissue, said system comprising

an energy source;

an emitter for contacting the tissue and thereby imparting energy from the source to the tissue to raise the temperature of the tissue;

a source of liquid which can be raised to a therapeutic temperature;

a chamber forming a passage fluidly coupled to the source of liquid and the emitter, the passage having a proximal end and a distal end proximate the emitter;

means for transporting the liquid from the proximal end to the distal end;

means for heating the liquid substantially only at the distal end of the passage from a first temperature below the therapeutic temperature to a second temperature at least as high as the therapeutic temperature; and

means for injecting the heated liquid into the tissue proximate to the emitter whereby the temperature of the volume of tissue is raised to a therapeutic level.

13. A method for the therapeutic treatment of a volume of tissue, comprising the steps of

imparting energy from an emitter to the tissue to raise the temperature of the tissue;

providing a source of liquid which can be raised to a therapeutic temperature;

providing a chamber forming a passage fluidly coupled to the source of liquid and the emitter, the passage having a proximal end and a distal end proximate the emitter;

transporting the liquid from the proximal end to the distal end;

heating the liquid substantially only at the distal end of the passage from a first temperature below the therapeutic temperature to a second temperature at least as high as the therapeutic temperature; and

injecting the heated liquid into the tissue proximate to the emitter whereby the temperature of the volume of tissue is raised to a therapeutic level.

14. The method of claim 13 wherein the energy is imparted by conducting a radio frequency current through the tissue.

18. The method of claim 13 wherein the energy is imparted by radiating lightwave energy into the tissue.

19. The method of claim 13 wherein the liquid is heated by conducting heat produced by a resistive element into the liquid.

20. The method of claim 13 wherein the liquid is heated by conducting a radio frequency current through the liquid.