Hyperthermia treatment and probe therefor

• US 20060287647A1
• Filed: 08/25/2006
• Published: 12/21/2006
• Est. Priority Date: 06/15/2001
• Status: Active Grant

• Current Assignee: Monteris Medical Incorporated (Monteris Medical US, Inc.)
• Original Assignee: Monteris Medical Incorporated (Monteris Medical US, Inc.)
• Inventors: Tyc, Richard, Torchia, Mark G., Pacak, John S.
• Granted Patent: US 7,691,100 B2
• Time in Patent Office: Days
• US Class Current: 606/10
• CPC Class Codes: A61B 18/1815 using microwaves
• CPC Class Codes: A61B 18/22 the beam being directed along or through a flexible conduit, e.g. an optical fibre; Couplings or hand-pieces therefor
• CPC Class Codes: A61B 18/24 with a catheter A61B18/26, A61B18/28 take precedence
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61B 2018/00011 with fluids
• CPC Class Codes: A61B 2018/00023 closed, i.e. without wound contact by the fluid
• CPC Class Codes: A61B 2018/2272 with reflective or refractive surfaces for deflecting the beam A61B2018/2261, A61B2018/2266 take precedence
• CPC Class Codes: A61B 2090/374 NMR or MRI

Abstract

An MRI guided surgical apparatus includes a heat source formed by a laser and an optical fiber carrying the heat energy into a part to be coagulated by hyperthermia with an end reflector to direct the energy in a beam to one side of the fiber end. A reinforcing sleeve for the fiber is mounted in a shielded, Piezo-electric motor which causes movement of the fiber longitudinally and angularly within a rigid elongate cannula. A magnetic resonance imaging system is arranged to generate a series of output signals over a period of time representative of temperature in the part as the temperature of the part changes during that time. The heat source is controlled in heat energy applied and location and orientation of the beam to stop heating when the temperature at the boundary of a tumor reaches the required hyperthermic temperature. Cooling of the tip portion of the probe is effected by expansion of a supplied cooling fluid in gaseous form through a restrictive orifice into an expansion zone at the probe end. The fiber is thus encased in a stiff tubular titanium probe with a relatively small fluid supply duct along the inside of the probe with the interior of the probe acting as a return duct for the expanded gas. Thus the fiber end is contained in gas rather than liquid and the temperature of the probe end can be monitored by a sensor in the probe end and controlled by controlling the pressure in the supplied cooling fluid. The probe is driven in the longitudinal and rotational directions to move the fiber tip.

Claims

1. A probe for use in effecting treatment in a patient comprising:

a heat source for applying heat to a volume within the patient;

a probe body mounting the heat source thereon for allowing invasive insertion of an end of the probe into the patient;

a supply duct on the probe body for a cooling fluid extending from a supply to the end of the probe;

the probe body being arranged to provide an expansion zone of reduced pressure at the end of the probe body so as to cause the cooling fluid to expand as a gas thus generating a cooling effect; and

,

a return duct on the probe body for return of the expanded gas from the end of the probe.

2. The probe according to claim 1 wherein the temperature of the probe is cooled to a temperature in the range of about zero to about minus 20 degrees Celsius.

3. The probe according to claim 1 wherein the return duct is of larger cross-sectional area than the supply duct.

4. The probe according to claim 3 wherein the return duct is of the order of 200 to 250 times larger than the supply duct.

5. The probe according to claim 1 wherein the probe body comprises an outer tube, wherein the supply duct is arranged inside the outer tube and wherein the return duct is defined by an inside surface of the outer tube.

6. The probe according to claim 5 wherein the supply duct is attached to an inside surface of the outer tube.

7. The probe according to claim 5 wherein the outer tube includes a heat energy supply conduit for transporting the heat energy from a supply to the end of the probe and wherein the heat energy supply conduit is attached to the inside surface of the outer tube.

8. The probe according to claim 1 wherein the cooling fluid is a gas which is expanded through a restricting orifice.

9. The probe according to claim 8 wherein the supply duct comprises a supply tube and the restricting orifice is formed by a reduced necking of the supply tube at an end thereof at the expansion zone.

10. The probe according to claim 1 wherein the probe body comprises an outer tube and the supply duct is mounted within the outer tube with the end thereof including the necking extending beyond an end of the outer tube.

11. The probe according to claim 1 wherein the heat source comprises a laser, an optical fiber for communicating light from the laser, and a light directing element at an end of the fiber, wherein the light directing element comprises a chamfered end of the fiber and wherein the chamfered end is located in the gas in the expansion zone.

12. The probe according to claim 11 wherein the chamfered end is arranged at 45 degrees.

13. The probe according to claim 11 wherein the chamfered end carries a coating arranged to reflect light at two different wavelengths.

14. The probe according to claim 11 wherein there is provided a temperature sensor at the end of the probe.

15. The probe according to claim 1 wherein the probe body comprises an outer tube and there is provided a temperature sensor mounted on the inside surface of the outer tube at the end of the probe.

16. The probe according to claim 1 wherein the temperature at the end of the probe is controlled by varying the pressure in the cooling fluid as supplied through the supply duct.

17. The probe according to claim 1 wherein the heat source comprises a laser and an optical fiber for communicating light from the laser to the end of the probe, and wherein the probe includes an outer tube and a transparent capsule enclosing an end of the outer tube with the fiber extending to a position beyond the end of the outer tube into the capsule.