Method and apparatus for tissue ablation

Patent metadata

Field	Value
Publication number	US-9561068-B2
Application number	US-201514594444-A
Country	US
Kind code	B2
Filing date	Jan 12, 2015
Priority date	Oct 6, 2008
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

Ablation catheters and systems include multiple inline chambers for containing and heating an ablative agent. The heating chamber includes one or more channels to increase the contact surface area of the ablative agent with the walls of the heating chamber to provide more efficient heating. Induction heating is used to heat a chamber and vaporize a fluid within by wrapping a coil about a ferromagnetic chamber and providing an alternating current to the coil. A magnetic field is created in the area surrounding the chamber which induces electric current flow in the chamber, heating the chamber and vaporizing the fluid inside. Positioning elements help maintain the device in the proper position with respect to the target tissue and also prevent the passage of ablative agent to normal tissues.

First claim

We claim:

1. A steam-based ablation system comprising:
a sterile, single use disposable fluid circuit comprising:
a water reservoir containing water, wherein the water reservoir is a pliable plastic bag or a syringe;
a water heating chamber having a length, wherein the water heating chamber comprises a non-ferromagnetic material having a lumen extending therethrough and a ferromagnetic material positioned within said lumen and wherein the ferromagnetic material is separated from the non-ferromagnetic material, across the length of the water heating chamber, by a space;
a catheter comprising a proximal end and a distal end, wherein the distal end comprises one or more ports; and
a contiguous fluid channel connecting said water reservoir, said water heating chamber, and the proximal end of said catheter, wherein the disposable fluid circuit does not comprise any ports or openings, other than the one or more ports in the catheter, for expelling water out from the disposable fluid circuit or for receiving water from an external source, wherein, prior to use, a portion of the contiguous fluid channel positioned between the water reservoir and the water heating chamber is blocked by a fracture diaphragm, thereby blocking the water from passively flowing from the water reservoir to the water heating chamber and wherein, during use, said fracture diaphragm is adapted to be ruptured by an increase in water pressure to permit the water to flow from the water reservoir to the water heating chamber;

an induction chamber adapted to receive said water heating chamber, wherein said induction chamber comprises a plurality of coils for receiving an electrical current and for generating a magnetic field;
an induction circuit for delivering said electrical current to said induction chamber; and
a pump or motor for applying a force to said water in the water reservoir in order to move the water from the water reservoir and into the water heating chamber.

2. The steam-based ablation system of claim 1 , wherein the induction circuit is adapted to generate a sinusoidal wave form and comprises a switching circuit having a resonant tank circuit.

3. The steam-based ablation system of claim 1 , wherein the non-ferromagnetic material is electrically insulating.

4. The steam-based ablation system of claim 3 , wherein, during operation, a lumen surface of the non-ferromagnetic material is configured to be heated to a temperature greater than 100 degrees Celsius.

5. The steam-based ablation system of claim 4 , wherein, during operation, an external surface of the non-ferromagnetic material is configured to be heated to a temperature no greater than 100 degrees Celsius.

6. The steam-based ablation system of claim 1 , wherein the induction chamber comprises a substantially cylindrical volume around which said plurality of coils are positioned and a lumen positioned within said substantially cylindrical volume adapted to receive said water heating chamber.

7. The steam-based ablation system of claim 1 , wherein said water is at least one of ionized water, non-ionized water, sterile water, and a solution of metal salt and water.

8. The steam-based ablation system of claim 1 , further comprising a circuit to generate to said electrical current, wherein the electrical current has a frequency of between 100 Hz and 100 kHz.

9. The steam-based ablation system of claim 1 , wherein, during operation, the water heating chamber and the induction chamber are magnetically coupled and wherein a conversion of magnetic energy into heat within the water heating chamber has an efficiency of greater than 60%.

10. The steam-based ablation system of claim 1 , wherein the non-ferromagnetic material is a cylinder and the ferromagnetic material is a metal rod.

11. The steam-based ablation system of claim 1 , wherein the ferromagnetic material comprises any one of, or alloys of, iron, nickel, stainless steel, manganese, silicon, carbon, copper, electrically conducting material, electrically insulating material or a Curie material having a Curie temperature between 60° C. and 500° C.

12. The steam-based ablation system of claim 1 , wherein the steam-based ablation system is configured such that a temperature of an external surface of said water heating chamber does not increase by more than 500 percent of its pre-operation external surface temperature during five minutes or less of continuous operation.

13. The steam-based ablation system of claim 1 , wherein the steam-based ablation system is configured such that, during operation, a temperature of an external surface of said water heating chamber does not exceed 120 degrees Celsius.

14. The steam-based ablation system of claim 1 , further comprising a thermocouple wherein said thermocouple is positioned within said heating chamber.

15. A steam-based ablation system comprising:
a disposable fluid circuit comprising:
a water reservoir containing water;
a water heating chamber having a length, wherein the water heating chamber comprises a volume of non-ferromagnetic material having a lumen extending therethrough and a ferromagnetic cylindrical rod, having a thermal capacity of 0.05 cal/K to 1 Mcal/K, positioned within said lumen;
a catheter comprising a proximal end and a distal end, wherein the distal end comprises one or more ports; and
a contiguous fluid channel connecting said water reservoir, said water heating chamber, and the proximal end of said catheter, wherein the disposable fluid circuit does not comprise any ports or openings, other than the one or more ports in the catheter, for expelling water out from the disposable fluid circuit or for receiving water from an external source, wherein, prior to use, a portion of the contiguous fluid channel positioned between the water reservoir and the water heating chamber is blocked by a fracture diaphragm, thereby blocking the water from passively flowing from the water reservoir to the water heating chamber and wherein, during use, said barrier is adapted to be ruptured by an increase in water pressure to permit the water to flow from the water reservoir to the water heating chamber;

an induction chamber adapted to receive said water heating chamber, wherein said induction chamber comprises a plurality of coils for receiving an electrical current and for generating a magnetic field; and
an induction circuit for delivering said electrical current to said induction chamber.

16. The steam-based ablation system of claim 15 , further comprising a pump for applying a force to said water in the water reservoir in order to rupture said fracture diaphragm and move the water from the water reservoir, through the water heating chamber, and into the catheter.

17. The steam-based ablation system of claim 15 , further comprising a motor for applying a force to said water in the water reservoir in order to rupture said fracture diaphragm and move the water from the water reservoir, through the water heating chamber, and into the catheter.

18. The steam-based ablation system of claim 15 , wherein the water reservoir is elevated relative to the water heating chamber and wherein the water in said water reservoir is gravity fed into the water heating chamber.

19. The steam-based ablation system of claim 15 , wherein the water reservoir comprises at least one of a pliable plastic bag, a syringe, and a bladder tank.

20. A steam-based ablation system comprising:
a disposable fluid circuit comprising:
a pliable plastic bag containing water;
a water heating chamber having a length, wher

Assignees

• Sharma Virender K
• Jabs Harry

Inventors

• Sharma Virender K
• Jabs Harry

Classifications

• A61B2018/00821

  measured by a thermocouple · CPC title

• A61B2018/00494

  Stomach, intestines or bowel · CPC title

• A61B2018/00791

  Temperature · CPC title

• A61M2205/3368

  Temperature · CPC title

• A61B2018/00285

  Balloons · CPC title