Therapeutic endo-rectal probe and apparatus constituting an application thereof for destroying cancer tissue, in particular of the prostate, and preferably in combination with an imaging endo-cavitary-probe

• US 5,474,071 A
• Filed: 02/22/1994
• Issued: 12/12/1995
• Est. Priority Date: 03/05/1991
• Status: Expired due to Term

• Current Assignee: Technomed Medical Systems
• Original Assignee: Institut National De La Sante Et De La Recherche Medicale (Inserm) (Allianz Global Investors GmbH), Technomed Medical Systems
• Inventors: Chapelon, Jean Y., Cathignol, Dominique, Blanc, Emmanuel, Gelet, Albert
• Primary Examiner(s): Manuel, George
• Assistant Examiner(s): Casler, Brian L.
• Application Number:
  US08/200,877
• Time in Patent Office: 658 Days
• Field of Search: 128/653.1, 128/660.03, 128/660.01, 128/660.02, 128/662.03, 128/662.06, 604/22, 606/128, 607/2, 607/4, 607/105, 607/97, 601/3
• US Class Current: 600/439
• CPC Class Codes: A61B 17/22004 using mechanical vibrations, e.g. ultrasonic shock waves A61B17/225 takes precedence
• CPC Class Codes: A61B 17/22012 in direct contact with, or very close to, the obstruction or concrement for removing obstructions in blood vessels by laser A61B18/245
• CPC Class Codes: A61B 17/2202 the ultrasound transducer being inside patient's body at the distal end of the catheter
• CPC Class Codes: A61B 2017/00274 Prostate operation, e.g. prostatectomy, turp, bhp treatment
• CPC Class Codes: A61B 2017/22021 electric leads passing through the catheter
• CPC Class Codes: A61B 2017/22025 applying a shock wave A61B2017/22091 takes precedence
• CPC Class Codes: A61B 2017/22028 arrays, e.g. phased arrays
• CPC Class Codes: A61B 2018/00547 Prostate
• CPC Class Codes: A61N 7/02 Localised ultrasound hyperthermia hyperthermia in general A61F7/00
• CPC Class Codes: A61N 7/022 intracavitary
• CPC Class Codes: B06B 1/06 operating with piezoelectric effect or with electrostriction piezoelectric or electrostrictive devices per se H10N30/00

Abstract

A therapeutic endo-rectal probe comprises a piezoelectric transducer element mounted in a support member itself connected to a rigid guide means enabling endo-rectal insertion of the probe, the outside shape of the support member preferably being that of a disk having an outline that is for the most part substantially circular or substantially elliptical, thereby facilitating endo-rectal insertion.

Claims

1. A probe for insertion in a body cavity, comprising:

at least one piezoelectric transducer element for effecting therapeutic treatment and having a predetermined maximum cross-sectional perimeter, said piezoelectric transducer element having a front face defining a surface area for emitting ultrasound waves focused at a focus for effecting said therapeutic treatment, and a rear face;

a probe support member having a proximal end and a distal end and defining a longitudinal axis, said piezoelectric transducer element being mounted on said probe support member at the distal end thereof, said distal end of said probe support member having a maximum cross-sectional perimeter conforming closely to said maximum cross-sectional perimeter of said piezoelectric transducer element for facilitating insertion of said probe in said body cavity and maximizing the surface area of said front face of said piezoelectric transducer element; and

a flexible membrane mounted to said probe support member and surrounding said distal end of said probe support member and said transducer element for providing a fluid seal thereabout, and means extending from the proximal end of said probe support member to said membrane for communicating fluid from said proximal end of said probe support member to said membrane for expanding same, whereby, the efficiency of said ultrasound waves for therapeutic treatment is maximized.

2. The probe according to claim 1, wherein said front face of said transducer element has a shape selected from the group consisting of substantially circular, substantially circular with truncated longitudinally extending side portions, and substantially elliptical.

3. The probe according to claim 2, wherein said probe support member has a front face defining an opening for receiving said transducer element, said front face of said transducer element confronting said front face of said support member when said transducer element is received in said opening.

4. The probe according to claim 3, wherein said maximum cross-sectional perimeter of said probe support member is less than about 16 cm.

5. The probe according to claim 4, further comprising a flexible membrane mounted to said probe support member and surrounding said distal end of said probe support member and said transducer element for providing a fluid seal thereabout, and means extending from the proximal end of said probe support member to said membrane for communicating fluid from said proximal end of said probe support member to said membrane for expanding same.

6. The probe according to claim 5, further comprising means for sealing said transducer element to said probe support member for preventing fluid at said front face of said transducer element from reaching said rear face thereof.

7. The probe according to claim 5, wherein the ratio of a diameter d of said front face of said transducer element to the focal length F of said transducer element is 0.5 to about 1.5.

8. The probe according to claim 7, wherein the shape of said front face of said transducer element is substantially circular with truncated longitudinally extending side portions, and wherein the ratio of the diameter of said front face of said transducer element in the longitudinal direction divided by the diameter in a direction perpendicular thereto is in the range of 1 to 2.

9. The probe according to claim 8, further comprising an imaging endo-cavitary probe for generating an image of said focus for monitoring said therapeutic treatment.

10. The probe according to claim 8, wherein said imaging endo-cavitary probe is secured to said probe support member.

11. The probe according to claim 1, wherein said probe support member has a front face defining an opening for receiving said transducer element, said front face of said transducer element confronting said front face of said probe support member when said transducer element is received in said opening.

12. The probe according to claim 11, wherein said front face of said transducer element is concave.

13. The probe according to claim 11, further comprising a backing layer disposed between said rear face of said transducer element and said probe support member for improving the performance of said transducer element.

14. The probe according to claim 1, wherein said maximum cross-sectional perimeter of said probe support member is about 16 cm.

15. The probe according to claim 1, further comprising electrical conducting means extending from the proximal end of said probe support member to the distal end thereof and connected at said distal end to the rear face of said transducer element.

16. The probe according to claim 1, further comprising means for sealing said transducer element to said probe support member for preventing fluid at said front face of said transducer element from reaching said rear face thereof.

17. The probe according to claim 1, wherein said membrane comprises radial deformation means for enhancing radial expansion of said membrane relative to longitudinal deformation.

18. The probe according to claim 1, wherein said membrane is mounted to said probe support member for longitudinal movement of said probe support member relative to said membrane.

19. The probe according to claim 1, wherein said piezoelectric transducer element is constructed from a material selected from the group consisting of piezoelectric ceramics and composite piezoelectric ceramics.

20. The probe according to claim 1, wherein said piezoelectric transducer element is selected from the group consisting of a monolithic design and a mosaic design comprising a plurality of transducer elements.

21. The probe according to claim 20, wherein said transducer element comprises a spherical cap for focusing the ultrasound waves generated thereby.

22. The probe according to claim 20, wherein said piezoelectric transducer element is a mosaic design comprising a plurality of transducer elements, and further comprising electronic means connected to said transducer elements for focusing at said focus the ultrasound waves emitted thereby.

23. The probe according to claim 1, wherein the ratio of a diameter d of said front face of said transducer element to the focal length F of said transducer element is 0.5 to about 1.5.

24. The probe according to claim 23, wherein said ratio is about 0.8 to about 1.2.

25. The probe according to claim 24, wherein said ratio is about 1.0.

26. The probe according to claim 1, further comprising an imaging endo-cavitary probe for generating an image of said focus for monitoring said therapeutic treatment.

27. The probe according to claim 26, wherein said imaging endo-cavitary probe is secured to said probe support member.

28. A probe for insertion in a body cavity, comprising:

at least one piezoelectric transducer element for effecting therapeutic treatment and having a predetermined maximum cross-sectional perimeter, said piezoelectric transducer element having a front face defining a surface area for emitting ultrasound waves focused at a focus for effecting said therapeutic treatment, and a rear face; and

a probe support member having a proximal end and a distal end and defining a longitudinal axis, said piezoelectric transducer element being mounted on said probe support member at the distal end thereof, said distal end of said probe support member having a maximum cross-sectional perimeter conforming closely to said maximum cross-sectional perimeter of said piezoelectric transducer element for facilitating insertion of said probe in said body cavity and maximizing the surface area of said front face of said piezoelectric transducer element, the shape of said front face of said transducer element is substantially circular with truncated longitudinally extending side portions, and wherein the ratio of the diameter of said front face of said transducer element in the longitudinal direction divided by the diameter in a direction perpendicular thereto is in the range of 1 to 2.

29. A probe for insertion in a body cavity, comprising:

at least one piezoelectric transducer element for effecting therapeutic treatment and having a predetermined maximum cross-sectional perimeter, said piezoelectric transducer element having a front face defining a surface area for emitting ultrasound waves focused at a focus for effecting said therapeutic treatment, and a rear face;

a probe support member having a proximal end and a distal end and defining a longitudinal axis, said piezoelectric transducer element being mounted on said probe support member at the distal end thereof, said distal end of said probe support member having a maximum cross-sectional perimeter conforming closely to said maximum cross-sectional perimeter of said piezoelectric transducer element for facilitating insertion of said probe in said body cavity and maximizing the surface area of said front face of said piezoelectric transducer element; and

,

an imaging endo-cavitary probe for generating an image of said focus for monitoring said therapeutic treatment, the proximal end of said probe support member comprises a rigid guide member, and wherein said imaging endo-cavitary probe is secured to said rigid guide member for axial movement relative thereto.

30. A probe for insertion in a body cavity, comprising:

at least one piezoelectric transducer element for effecting therapeutic treatment and having a predetermined maximum cross-sectional perimeter, said piezoelectric transducer element having a front face defining a surface area for emitting ultrasound waves focused at a focus for effecting said therapeutic treatment, and a rear face;

a probe support member having a proximal end and a distal end and defining a longitudinal axis, said piezoelectric transducer element being mounted on said probe support member at the distal end thereof, said distal end of said probe support member having a maximum cross-sectional perimeter conforming closely to said maximum cross-sectional perimeter of said piezoelectric transducer element for facilitating insertion of said probe in said body cavity and maximizing the surface area of said front face of said piezoelectric transducer element; and

an imaging endo-cavitary probe for generating an image of said focus for monitoring said therapeutic treatment, said piezoelectric transducer element having an acoustic window therein, and said imaging endo-cavitary probe being positioned beneath said acoustic window.

31. A method for treating a tumor volume, comprising:

providing an endo-rectal therapeutic probe having a longitudinal axis and incorporating emitting means for emitting ultrasound waves focused at a focus;

providing an imaging endo-cavitary probe having a longitudinal axis for imaging an image plane;

inserting the endo-rectal probe into the rectum until said emitting means confronts the tumor volume to be treated;

inserting the imaging endo-cavitary probe into a non-rectal cavity until the image plane of the endo-cavitary probe includes said focus for observing the focus of the ultrasound waves emitted by said endo-rectal probe; and

simultaneously displacing in translation the endo-rectal probe and the endo-cavitary probe for treating the entire volume of the tumor while observing the focus of the endo-rectal probe.

32. The method according to claim 31, further comprising the step of rotating at least one of said probes about their respective longitudinal axes.

33. The method according to claim 31, further comprising the step of adjusting the relative positions of said endo-rectal and endo-cavitary probes for establishing said focus in said image plane whereby said focus remains in said image plane for imaging by said imaging endo-cavitary probe during said step of simultaneously displacing said probes in translation.

34. The method of claim 31, wherein said step of providing an imaging endo-cavitary probe comprises providing an imaging endo-urethral probe, and wherein said step of treating the entire volume of the tumor comprises treating the entire volume of a tumor in the prostate.

35. Apparatus for treating a tumor volume, comprising:

an endo-rectal therapeutic probe having a longitudinal axis and incorporating emitting means for emitting ultrasound waves focused at a focus, said endo-rectal probe being insertable into the rectum until said emitting means confronts the tumor volume to be treated;

an imaging endo-cavitary probe having a longitudinal axis for imaging an image plane, said imaging endo-cavitary probe being insertable into a non-rectal cavity until the image plane of the endo-cavitary probe includes said focus for observing the focus of the ultrasound waves emitted by said endo-rectal probe; and

means for simultaneously displacing in translation the endo-rectal probe and the endo-cavitary probe for treating the entire volume of the tumor while observing the focus of the endo-rectal probe.

36. The apparatus according to claim 35, further comprising means for rotating at least one of said probes about their respective longitudinal axes.

37. The apparatus according to claim 35, further comprising means for adjusting the relative positions of said endo-rectal and endo-cavitary probes for establishing said focus in said image plane whereby said focus remains in said image plane for imaging by said imaging endo-cavitary probe during treatment of said tumor volume.

38. The apparatus according to claim 37, wherein said means for adjusting the relative positions of said endo-rectal and endo-cavitary probes comprises a common support and means for coupling said endo-rectal and endo-cavitary probes to said common support for independent movement relative thereto.

39. The apparatus according to claim 35, wherein said imaging endo-cavitary probe comprises an imaging endo-urethral probe.

40. A probe for insertion in a body cavity, comprising:

a probe support member having a proximal end and a distal end and defining a longitudinal axis;

at least one piezoelectric transducer element operative to emit ultrasound waves at a focus and effective for therapeutic treatment of body tissue and having a predetermined maximum cross-sectional perimeter, said piezoelectric transducer element being mounted on said probe support member at the distal end thereof, said piezoelectric transducer element being of a substantially disk shape, having a rear face and front face, said front face defining a surface area also of substantially disk shape and disposed substantially parallel to said longitudinal axis for emitting said ultrasound waves in a direction transversely to said longitudinal axis and focused at a focus for effecting said therapeutic treatment at said focus;

said distal end of said probe support member having a maximum cross-sectional perimeter conforming closely to said maximum cross-sectional perimeter of said piezoelectric transducer element of substantially disk shape for facilitating insertion of said probe in said body cavity and for maximizing the emitting surface area of said piezoelectric transducer element, whereby the efficiency of said transducer element in delivering said ultrasound waves at said focus is maximized;

a flexible membrane mounted to said probe support member and surrounding said distal end of said probe support member and said transducer element for providing a fluid seal thereabout; and

means extending from the proximal end of said probe support member to said membrane for communicating fluid from said proximal end of said probe support member to said membrane for expanding said membrane.

41. The probe according to claim 40, further comprising means for sealing said transducer element to said probe support member for preventing fluid at said front face of said transducer element from reaching said rear face thereof.

42. The probe according to claim 40, wherein said membrane comprises radial deformation means for enhancing radial expansion of said membrane.

43. The probe according to claim 40, wherein said membrane is mounted to said probe support member for longitudinal movement of said probe support member relative to said membrane.

44. The probe according to claim 40, wherein said piezoelectric transducer element is constructed from material selected from the group consisting of piezoelectric ceramics and composite piezoelectric ceramics.

45. The probe according to claim 40, wherein said piezoelectric transducer element is a mosaic design comprising a plurality of transducer elements, and further comprising electronic means connected to said transducer elements for focusing at said focus the ultrasound waves emitted thereby.

46. The probe according to claim 40, wherein the ratio of a diameter d of said front face of said transducer element to the focal length F of said transducer element is 0.5 to about 1.5.

47. The probe according to claim 46, wherein said ratio is about 0.8 to about 1.2.

48. The probe according to claim 47, wherein said ratio is about 1.0.

49. A probe for insertion in a body cavity, comprising:

a probe support member having a proximal end and a distal end and defining a longitudinal axis;

at least one piezoelectric transducer element operative to emit ultrasound waves at a focus and effective for therapeutic treatment of body tissue and having a predetermined maximum cross-sectional perimeter, said piezoelectric transducer element being mounted on said probe support member at the distal end thereof, said piezoelectric transducer element being of substantially disk shape, having a rear face and a front face, said front face defining a surface area having substantially circular shape with truncated longitudinally extending side portions, said front face being dimensioned so that the ratio of the diameter of said front face of said transducer element in the longitudinal direction divided by the diameter in a direction perpendicular thereto is in the range of 1 to 2;

said front face being disposed substantially parallel to said longitudinal axis for emitting said ultrasound waves transversely to said longitudinal axis and focused at a focus for effecting said therapeutic treatment at said focus; and

said distal end of said probe support member having a maximum cross-sectional perimeter conforming closely to said maximum cross-sectional perimeter of said piezoelectric transducer element of substantially disk shape for facilitating insertion of said probe in said body cavity and maximizing the emitting surface area of said piezoelectric transducer element, whereby the efficiency of said transducer element in delivering said ultrasound waves at said focus is maximized.

50. A probe for insertion in a body cavity, comprising:

a probe support member having a proximal end and a distal end and defining a longitudinal axis, said proximal end comprising a rigid guide member;

at least one piezoelectric transducer element operative to emit ultrasound waves at a focus and effective for therapeutic treatment of body tissue and having a predetermined maximum cross-sectional perimeter, said piezoelectric transducer element being mounted on said probe support member at the distal end thereof, said piezoelectric transducer element being of substantially disk shape, having a rear face and a front face;

said front face being disposed substantially parallel to said longitudinal axis for emitting said ultrasound waves transversely to said longitudinal axis and focused at a focus for effecting said therapeutic treatment at said focus;

an imaging endo-cavitary probe for generating an image of said focus for monitoring said therapeutic treatment, said endo-cavitary probe being secured to said rigid guide member for axial movement relative to said rigid guide member;

said distal end of said probe support member having a maximum cross-sectional perimeter conforming closely to said maximum cross-sectional perimeter of said piezoelectric transducer element of substantially disk shape for facilitating insertion of said probe in said body cavity and maximizing the emitting surface area of said piezoelectric transducer element, whereby the efficiency of said transducer element in delivering said ultrasound waves at said focus is maximized.

51. A probe for insertion in a body cavity, comprising:

a probe support member having a proximal end and a distal end and defining a longitudinal axis;

at least one piezoelectric transducer element having an acoustic window therein and operative to emit ultrasound waves at a focus and effective for therapeutic treatment of body tissue and having a predetermined maximum cross-sectional perimeter, said piezoelectric transducer element being mounted on said probe support member at the distal end thereof, said piezoelectric transducer element being of substantially disk shape, having a rear face and a front face;

said front face being disposed substantially parallel to said longitudinal axis for emitting said ultrasound waves transversely to said longitudinal axis and focused at a focus for effecting said therapeutic treatment at said focus;

an imaging endo-cavitary probe for generating an image of said focus for monitoring said therapeutic treatment, said endo-cavitary probe being positioned beneath said acoustic window;

said distal end of said probe support member having a maximum cross-sectional perimeter conforming closely to said maximum cross-sectional perimeter of said piezoelectric transducer element of substantially disk shape for facilitating insertion of said probe in said body cavity and maximizing the emitting surface area of said piezoelectric transducer element, whereby the efficiency of said transducer element in delivering said ultrasound waves at said focus is maximized.

52. A probe for insertion in a body cavity, comprising:

a probe support member having a proximal end and a distal end having a front face defining an opening therein, said support member defining a longitudinal axis;

at least one piezoelectric transducer element operative to emit ultrasound waves at a focus effective for therapeutic treatment of body tissue and having a predetermined maximum cross-sectional perimeter, said piezoelectric transducer element being of a substantially disk shape having a rear face and a front face, and being mounted in said opening with the front face of said transducer element confronting the front face of said support member;

said front face defining a surface area also of substantially disk shape which is disposed substantially parallel to said longitudinal axis for emitting said ultrasound waves transversely to said longitudinal axis and focused at a focus for effecting said therapeutic treatment at said focus;

said distal end of said probe support member having a maximum cross-sectional perimeter conforming closely to said maximum cross-sectional perimeter of said piezoelectric transducer element of substantially disk shape for facilitating insertion of said probe in said body cavity and maximizing the emitting surface area of said piezoelectric transducer element, whereby the efficiency of said transducer in delivering said ultrasound waves at said focus is maximized.

53. A method for treating a body zone located inside the body of a patient, comprising the steps of:

providing a probe for insertion in a body cavity near said body zone of said patient, said probe including at least one piezoelectric transducer element operative to emit ultrasound waves at a focus effective for therapeutic treatment of the body tissue and having a predetermined maximum cross-sectional perimeter, said piezoelectric transducer element having a front face defining a surface area for emitting ultrasound waves focused at a focus for effecting said therapeutic treatment, and a rear face, and further including a probe support member having a proximal end and a distal end and defining a longitudinal axis, said piezoelectric transducer element being mounted on said probe support member at the distal end thereof, said distal end of said probe support member having a maximum cross-sectional perimeter conforming closely to said maximum cross-sectional perimeter of said piezoelectric transducer element for facilitating insertion of said probe in said body cavity and maximizing the surface area of said front face of said piezoelectric transducer element;

providing a flexible membrane mounted to said probe support member and surrounding said distal end of said probe support member and said transducer element for providing a fluid seal thereabout and defining a chamber between said membrane and said probe support member;

inserting said probe into said body cavity near said body zone to be treated, with said front face of said piezoelectric transducer element in front of said body zone to be treated, said focus being located in said body zone;

providing means extending from the proximal end of said probe support member to said membrane for communicating fluid from said proximal end of said probe support member to said membrane for expanding same;

inflating said membrane after said probe is inserted into said body cavity near said body zone to be treated for moving said membrane into contact with the inside wall of the body cavity; and

causing said piezoelectric transducer element to emit ultrasound waves effective for said therapeutic treatment at said focus in said body zone.

54. The method of claim 53, wherein said body zone is a tumor located inside the body of a patient.

55. The method of claim 53, wherein said body zone is a prostate tumor.

56. The method of claim 55, including:

providing said probe, comprising said at least one piezoelectric transducer element and said probe support member, as an endorectal therapeutic probe having a longitudinal axis;

inserting said endorectal probe into the rectum until said front face confronts the prostate tumor volume to be treated;

causing said piezoelectric transducer element to emit ultrasound waves effective for said therapeutic treatment at said focus; and

displacing said endorectal probe for treating the entire volume of the tumor.

57. The method of claim 53, wherein said causing step includes causing said piezoelectric transducer element to emit ultrasound waves pulsed at a frequency in the range from 1 MHz to 4 MHz with pulses of short duration ranging between 50 milliseconds and 5 seconds.

58. The method of claim 53, including delivering an intensity at the focus in the range from 1,000 W/cm² to 10,000 W/cm².

59. The method of claim 57, wherein the pulses have a short duration ranging between 200 milliseconds and 2 seconds.

60. The method of claim 53, including selecting the shape of the front face of said transducer element from the group consisting of substantially circular, substantially circular with truncated longitudinally extending side portions, and substantially elliptical.

61. The method of claim 53, wherein said providing step comprises providing a probe having a probe support member including a front face defining an opening for receiving said transducer element, said rear face of said transducer element confronting said front face of said probe support member when said transducer element is received in said opening.

62. The method of claim 53, wherein said maximum cross-sectional perimeter of said probe support member is about 16 cm.

63. The method of claim 53, including providing said membrane with radial deformation means for enhancing radial expansion of said membrane relative to longitudinal deformation.

64. The method of claim 53, further providing a piezoelectric transducer element having the ratio of a diameter d of said front face of said transducer element to the focal length F of said transducer element ranging between about 0.5 and about 1.5.

65. The method of claim 64, wherein said ratio is ranging between about 0.8 and about 1.2.

66. The method claim 53, further comprising providing an imaging endocavitary probe for generating an image of said focus for monitoring said therapeutic treatment.

67. The method of claim 66, further comprising securing said imaging endocavitary probe to said probe support member.

68. A method for treating a body zone located inside the body of a patient, comprising the steps of:

providing a probe for insertion in a body cavity near said body zone of said patient, said probe including a probe support member having a proximal end and a distal end and defining a longitudinal axis;

at least one piezoelectric transducer element mounted on said probe support member at the distal end thereof, said piezoelectric transducer element being operative to emit ultrasound waves at a focus effective for therapeutic treatment of body tissue and having a predetermined maximum cross-sectional perimeter, said piezoelectric transducer element having a rear face and a front face, said front face having a substantially circular shape and truncated longitudinally extending side portions, wherein the ratio of the diameter of said front face of said transducer element in the longitudinal direction divided by the diameter in a direction perpendicular thereto is in the range of 1 to 2, said front face defining a surface area for emitting ultrasound waves focused at a focus for effecting said therapeutic treatment;

said distal end of said probe support member having a maximum cross-sectional perimeter conforming closely to said maximum cross-sectional perimeter of said piezoelectric transducer element for facilitating insertion of said probe in said body cavity and maximizing the surface area of said front face of said piezoelectric transducer element;

inserting said probe into said body cavity near said body zone to be treated with said front face of said piezoelectric transducer element in front of said body zone to be treated, said focus being located in said body zone; and

causing said piezoelectric transducer element to emit ultrasound waves effective for said therapeutic treatment at said focus in said body zone.

69. A method for treating a body zone located inside the body of a patient, comprising the steps of:

providing a probe for insertion in a body cavity near said body zone of said patient, said probe including at least one piezoelectric transducer element operative to emit ultrasound waves at a focus effective for therapeutic treatment of body tissue and having a predetermined maximum cross-sectional perimeter, said piezoelectric transducer element having a rear face and a front face, said front face defining a surface area for emitting ultrasound waves focused at a focus for effecting said therapeutic treatment, and further including a probe support member having a proximal end and a distal end and defining a longitudinal axis, said piezoelectric transducer element having an acoustic window therein and being mounted on said probe support member at the distal end thereof, said distal end of said probe support member having a maximum cross-sectional perimeter conforming closely to said maximum cross-sectional perimeter of said piezoelectric transducer element for facilitating insertion of said probe in said body cavity and maximizing the surface area of said front face of said piezoelectric transducer element;

providing an imaging endo-cavitary probe secured to said probe support member and positioning said endo-cavitary probe beneath said acoustic window for generating an image of said focus for monitoring said therapeutic treatment;

inserting said probe into said body cavity near said body zone to be treated with said front face of said piezoelectric transducer element in front of said body zone to be treated, said focus being located in said body zone; and

causing said piezoelectric transducer element to emit ultrasound waves effective for said therapeutic treatment at said focus in said body zone.