System for Treatment of Diseased Tissue Using Controlled Ultrasonic Heating

• US 20110034833A1
• Filed: 07/06/2010
• Published: 02/10/2011
• Est. Priority Date: 03/09/2005
• Status: Active Grant

• Current Assignee: Sunnybrook Health Sciences Centre
• Original Assignee: Sunnybrook Health Sciences Centre
• Inventors: CHOPRA, Rajiv, BURTNYK, Mathieu, BRONSKILL, Michael
• Granted Patent: US 8,989,838 B2
• Time in Patent Office: Days
• US Class Current: 601/3
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61B 2018/00023 closed, i.e. without wound contact by the fluid
• CPC Class Codes: A61B 2090/374 NMR or MRI
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61N 2007/025 interstitial
• CPC Class Codes: A61N 7/02 Localised ultrasound hyperthermia hyperthermia in general A61F7/00

Abstract

The present invention provides a method and apparatus for delivering and controlling thermal therapy to a volume of diseased tissue. Specifically, the invention includes using thermal imaging and other inputs to determine an acoustic (ultrasonic) treatment regime employing interstitial ultrasound applicators to deliver a required therapeutic temperature or thermal dose to the affected region in a body or organ. Various aspects of the treatment that can be controlled include individual transducer element operating power and frequency, as well as the rate of cooling and rotation of the entire applicator.

Claims

31. A system for delivering thermal treatment to diseased tissue in a treatment volume, comprising:

an ultrasonic thermal applicator including at least one transducer element that is driven by a transducer driving signal having a driving frequency and a driving amplitude, said at least one transducer providing a nominally directional ultrasonic beam into the treatment volume;

an imaging apparatus adapted for acquiring thermal data from the treatment volume;

a treatment controller having an input from the imaging apparatus and an output to control said transducer driving signal, said transducer driving signal being at least partially dependent on said input from the imaging apparatus; and

a thermal applicator motion controller that can rotate said ultrasonic thermal applicator, and consequently said nominally directional ultrasonic beam, in an angular motion about an axial dimension of the ultrasonic thermal applicator.

32. The system of claim 31, wherein the ultrasonic thermal applicator comprises a multi-element transducer having at least two ultrasonic elements.

33. The system of claim 31, wherein the ultrasonic thermal applicator comprises an elongated member adapted for insertion into an interstitial space within the diseased tissue.

34. The system of claim 33, wherein the elongated member of the ultrasonic thermal applicator substantially defines an axis corresponding to a length of the applicator.

35. The system of claim 34, wherein the nominally directional ultrasonic beam comprises an ultrasound field projected from the ultrasonic thermal applicator into the treatment volume substantially along a plane parallel to said axis.

36. The system of claim 31, wherein said thermal applicator motion controller comprises a motor adapted for operation within a magnetic resonance imaging (MRI) chamber, and designed and arranged to apply a torque to rotate the thermal applicator about an axis of rotation.

37. The system of claim 31, wherein said thermal applicator motion controller comprises a bearing adapted for operation within a magnetic resonance imaging (MRI) chamber, and designed and arranged to provide a rotational degree of freedom to rotate the thermal applicator about an axis of rotation.

38. The system of claim 31, further comprising a fluid flow apparatus including a fluid flow channel proximal to the thermal applicator that provides temperature control to regions of space proximal to the fluid flow channel.

39. The system of claim 31, wherein the treatment controller is in communication with the motion controller to control a rate of rotation of the thermal applicator.

40. The system of claim 31, wherein the treatment controller comprises hardware and software for carrying out a pre-planned treatment regimen based on a set of initial conditions and information.

41. The system of claim 31, wherein the treatment controller comprises hardware and software for dynamically determining a treatment regimen based on conditions and information collected during the progress of a treatment.

42. The system of claim 31, wherein said motion controller provides a sequence of pulses that control a motor to rotate the thermal applicator about its axis, said sequence of pulses designed to minimize electromagnetic interference put out by the motion controller during use.

43. A method for controlling a thermal treatment of diseased tissue in a treatment volume, comprising:

measuring a spatial thermal distribution in at least a portion of the treatment volume;

determining whether a thermal treatment objective has been met within at least a portion of the treatment volume;

calculating a set of control parameters that control the heating of the diseased tissue in at least the portion of the treatment volume;

delivering a driving signal to a thermal applicator according to the calculated set of control parameters.

44. The method of claim 43, wherein the set of control parameters includes an operating frequency of the thermal applicator.

45. The method of claim 43, wherein the set of control parameters includes an operating power of the thermal applicator.

46. The method of claim 43, wherein the set of control parameters includes an angular rotation rate of the thermal applicator.

47. The method of claim 43, further comprising limiting a peak temperature in the treatment volume to some maximum temperature.

48. The method of claim 43, wherein measuring the spatial thermal distribution comprises measuring a spatial temperature distribution.

49. The method of claim 43, wherein measuring the spatial thermal distribution comprises measuring a thermal dose in at least a portion of the treatment volume.

50. The method of claim 43, further comprising comparing a thermal result from the thermal treatment with a computed result based on a bio-heat computation.