Gas-heated gas-cooled cryoprobe utilizing electrical heating and a single gas source

• US 20060122590A1
• Filed: 12/06/2004
• Published: 06/08/2006
• Est. Priority Date: 12/06/2004
• Status: Active Grant

• Current Assignee: Galil Medical Ltd. (Boston Scientific Corporation)
• Original Assignee: Galil Medical Ltd. (Boston Scientific Corporation)
• Inventors: Berzak, Nir, Amir, Uri, Bliweis, Mordechai, Leybin, Yura, Livneh, Shimon
• Granted Patent: US 7,846,154 B2
• Time in Patent Office: Days
• US Class Current: 606/24
• CPC Class Codes: A61B 18/02 by cooling, e.g. cryogenic techniques devices for cooling specific reflex points of the body within cell-life limits A61H39/06
• CPC Class Codes: A61B 18/082 Probes or electrodes therefor
• CPC Class Codes: A61B 2018/00041 Heating, e.g. defrosting
• CPC Class Codes: A61B 2018/046 in liquid form
• CPC Class Codes: A61B 2018/048 in gaseous form

Abstract

The present invention is of device, system, and method for cooling and heating an operating tip of a cryoprobe using a single source of compressed gas. Cooling of the operating tip is effected by Joule-Thomson expansion of a high-pressure cooling gas through a Joule-Thomson orifice into an expansion chamber. Heating of the operating tip is effected by electrical resistance heating. In preferred embodiments, heating of the operating tip is effected by electrical resistance heating of low-pressure gas flowing towards the operating tip. Preferably, gas from a single gas source is supplied to the probe during both cooling and heating phases, a cooling gas being supplied at high pressure when used for cooling and at low pressure when used for heating. Low-pressure gas supplied during the heating phase is heated as it flows towards the operating tip, preferably by electrical resistance heating within the body of the probe. A single gas input lumen is used during both cooling and heating phases to transport gas into the probe, and a single gas exhaust lumen is used during both cooling and heating phases to conduct gas out of the probe.

Claims

1. A cryoprobe useable to cryoablate tissue of a body, comprising:

(a) an operating tip operable to be cooled to cryoablation temperatures; and

(b) an electrical resistance heating element operable to heat said operating tip.

2. The cryoprobe of claim 1, wherein said electrical resistance heating element is positioned within said operating tip.

3. The cryoprobe of claim 1, wherein said electrical resistance heating element is positioned within said cryoprobe and external to said operating tip.

4. The cryoprobe of claim 1, wherein said operating tip is operable to be cooled by expansion of high-pressure cooling gas through an orifice.

5. The cryoprobe of claim 4, wherein said electrical resistance heating element is operable to heat a flow of gas directed through a gas lumen toward said operating tip.

6. The cryoprobe of claim 4, wherein said electrical resistance heating element is operable to heat a flow of gas directed through a gas input lumen to said orifice.

7. A cryoprobe useable to cryoablate tissue of a body, comprising an operating tip which includes a Joule-Thomson orifice, which operating tip is operable to be cooled by expansion of high-pressure cooling gas through said orifice, and wherein said operating tip further comprises an electrical resistance heating element.

8. A cryoprobe having an operating tip operable to be cooled by expansion of high-pressure cooling gas expanding through a Joule-Thomson orifice, and also operable to be heated by a flow of heated low-pressure cooling gas transiting said orifice.

9. A cryoprobe useable to cryoablate tissue of a body, comprising an operating tip which includes a Joule-Thomson orifice, which operating tip is operable to be cooled by expansion of high-pressure cooling gas through said orifice, and wherein said operating tip is further operable to be heated by flowing heated low-pressure gas directed to said operating tip.

10. The cryoprobe of claim 9, wherein a common gas input lumen is operable to deliver said high-pressure gas and said low-pressure gas to said operating tip.

11. The cryoprobe of claim 10, wherein a common gas input lumen is operable to deliver said high-pressure gas and said low-pressure gas to said orifice.

12. The cryoprobe of claim 9, wherein said heated low-pressure gas is directed to said orifice.

13. The cryoprobe of claim 9, further comprising a gas input lumen and an electrical resistance heating element proximate to a portion of said gas input lumen, wherein said electrical resistance heating element is operable to heat gas flowing within said gas input lumen.

14. The cryoprobe of claim 9, further comprising a thermal sensor.

15. The cryoprobe of claim 14, wherein said thermal sensor is a thermocouple.

16. The cryoprobe of claim 9, further comprising an electrical resistance heating element.

17. The cryoprobe of claim 16, wherein said electrical resistance heating element is operable to heat said flow of low-pressure gas.

18. The cryoprobe of claim 17, further comprising a heat-exchanging configuration which comprises an electrical resistance heating element.

19. The cryoprobe of claim 18, wherein said heat-exchanging configuration comprises a gas input lumen spirally wrapped around a central core.

20. The cryoprobe of claim 16, wherein said cryoprobe comprises a gas input lumen spirally wrapped around a central core, and said central core comprises said electrical resistance heating element.

21. The cryoprobe of claim 17, wherein said cryoprobe comprises a gas exhaust lumen containing an electrical resistance heating element and a portion of a gas input lumen.

22. The cryoprobe of claim 17, wherein said cryoprobe comprises a gas exhaust lumen, a gas input lumen at least a portion of which is contained within said gas exhaust lumen, and an electrical resistance heating element external to, and contiguous to, said gas exhaust lumen.

23. A cryoprobe comprising:

(a) a gas input lumen operable to direct high-pressure gas to a Joule-Thomson orifice; and

(b) an electrical resistance heating element operable to heat a low-pressure gas directed through said gas input lumen to said orifice.

24. A system for cryoablating tissue, comprising:

(a) A cryoprobe useable to cryoablate tissue of a body, which cryoprobe comprises an operating tip which includes a Joule-Thomson orifice, which operating tip is operable to be cooled by expansion of high-pressure cooling gas through said orifice, and wherein said operating tip is further operable to be heated by flowing heated low-pressure gas directed to said operating tip;

(b) a gas supply operable to supply high-pressure cooling gas to said cryoprobe and also operable to supply low-pressure cooling gas to said cryoprobe; and

(c) a power supply operable to supply electric power to a resistance element operable to heat a flow of low-pressure cooling gas.

25. The system of claim 24, wherein said resistance element is positioned within said cryoprobe.

26. The system of claim 24, wherein said resistance element is positioned within said operating tip.

27. The system of claim 24, wherein said resistance element is positioned within an expansion chamber contiguous to said orifice.

28. The system of claim 24, wherein said cryoprobe further comprises a heat exchanging configuration, and said heat exchanging configuration comprises said resistance element.

29. The system of claim 24, wherein said gas supply is further operable to supply high-pressure heating gas to said cryoprobe.

30. The system of claim 24, further comprising a control module operable to influence temperatures of said cryoprobe by regulating output of at least one of a group consisting of said power supply and said gas supply.

31. The system of claim 24, further comprising a control module operable to influence temperatures of said cryoprobe by regulating output of said power supply and by regulating output of said gas supply.

32. The system of claim 24, further comprising a current sensor and a power cut-off switch operable to cut power to said resistance element when current detected by said current sensor indicates that said resistance element has heated beyond a predetermined threshold.

33. The system of claim 24, further comprising a current sensor and a power cut-off switch operable to cut power to said resistance element when current detected by said current sensor falls below a predetermined threshold.

34. The system of claim 24, wherein said control system is operable to calculate an operational command for said power supply based on algorithmic analysis of data obtained from a thermal sensor.

35. The system of claim 34, wherein thermal sensor is a thermocouple.

36. The system of claim 24, wherein said control system is operable to calculate an operational command for said power supply based on algorithmic analysis of data obtained from a pressure sensor.

37. The system of claim 24, wherein said control system is operable to calculate an operational command for said power supply based on algorithmic analysis of data obtained from a current sensor.

38. The system of claim 24, wherein said control system is operable to calculate an operational command for said power supply based on algorithmic analysis of data obtained from a gas flow sensor.

39. The system of claim 38, wherein said gas flow sensor comprises an electrical resistance heating element whose resistance varies as a function of its temperature, and a current sensor operable to measure current flowing through said electrical resistance heating element.

40. The system of claim 24, wherein said cryoprobe is constructed of MRI-compatible material.

41. The system of claim 40, wherein said MRI-compatible material is selected from a group consisting of titanium and inconel.

42. The system of claim 40, wherein electrical components within and proximate to said cryoprobe are shielded with Mu-metal.

43. A method for using a cryoprobe to cryoablate tissues at a cryoablation target site within a body and for subsequently disengaging said cryoprobe from said cryoablation site, comprising:

(a) positioning an operating tip of said cryoprobe in a vicinity of a cryoablation target site;

(b) cooling said operating tip to cryoablation temperatures, thereby cryoablating tissues at said cryoablation target site; and

(c) utilizing an electrical resistance heating element within said cryoprobe to heat said operating tip, thereby thawing tissues contiguous to said operating tip;

thereby cryoablating tissue at said cryoablation target site and subsequently disengaging said cryoprobe from said cryoablation target site.

44. The method of claim 43, further including utilizing said electrical resistance heating element to heat a flow of gas directed through a gas input lumen to said operating tip.

45. The method of claim 43, further including utilizing said electrical resistance heating element to heat a flow of gas directed through a gas input lumen to a Joule-Thomson orifice in said operating tip.

46. A power cutoff system for a cryoprobe, comprising:

(a) an electrical resistance heating element for heating an operating tip of a cryoprobe;

(b) a current detector operable to report a measure of current passing through said electrical resistance heating element when said electrical resistance heating element is used to heat said operating tip;

(c) a power supply operable to supply power to said electrical resistance heating element; and

(d) a power cutoff switch operable to cut off power flow from said power supply to said electrical resistance element when said current detector detects a current inferior to a predetermined value.