Method and apparatus for photothermal treatment of tissue at depth

• US 20040093042A1
• Filed: 06/19/2003
• Published: 05/13/2004
• Est. Priority Date: 06/19/2002
• Status: Active Grant

• Current Assignee: Palomar Medical Technologies Incorporated (Hologic Incorporated), The General Hospital Corporation (Mass General Brigham, Inc.)
• Original Assignee: Palomar Medical Technologies Incorporated (Hologic Incorporated), The General Hospital Corporation (Mass General Brigham, Inc.)
• Inventors: Manstein, Dieter, Altshuler, Gregory B., Zenzie, Henry H., Anderson, R. Rox, Smirnov, Michael Z., Burke, James III, Erofeev, Andrei V., Radl, Andrew
• Granted Patent: US 7,351,252 B2
• Time in Patent Office: Days
• US Class Current: 607/88
• CPC Class Codes: A61B 18/14 Probes or electrodes therefor
• CPC Class Codes: A61B 18/203 applying laser energy to the outside of the body
• CPC Class Codes: A61B 2018/00005 Cooling or heating of the probe or tissue immediately surrounding the probe
• CPC Class Codes: A61B 2018/00011 with fluids
• CPC Class Codes: A61B 2018/00452 Skin
• CPC Class Codes: A61B 2018/00458 Deeper parts of the skin, e.g. treatment of vascular disorders or port wine stains
• CPC Class Codes: A61B 2018/00476 Hair follicles
• CPC Class Codes: A61N 1/32 alternating or intermittent currents applying electric fields by inductive or capacitive coupling A61N1/40; microwave apparatus A61N5/02
• CPC Class Codes: A61N 2007/0008 Destruction of fat cells
• CPC Class Codes: A61N 5/0613 Apparatus adapted for a specific treatment
• CPC Class Codes: A61N 7/00 Ultrasound therapy lithotripsy A61B17/22, A61B17/225; massage using supersonic vibration A61H23/00 ; using ultrasound for introducing media into the body A61M37/0092

Abstract

The present invention provides method and apparatus for treating tissue in a region at depth by applying optical radiation thereto of a wavelength able to reach the depth of the region and of a selected relatively low power for a duration sufficient for the radiation to effect the desired treatment while concurrently cooling tissue above the selected region to protect such tissue. Treatment may be enhanced by applying mechanical, acoustic or electrical stimulation to the region.

Claims

1. Apparatus for treating at least a selected region at depth of a patient while protecting tissue above the selected region, comprising:

an optical radiation source for delivering optical radiation at a power of between 0.2-50 W/cm² to the patient'"'"'s skin, said power varying at least in part as a function of the depth of said selected region, said optical radiation being applied to said selected region for at least approximately 2 seconds; and

a cooling mechanism for cooling tissue above said selected region to a temperature below that of said selected region.

2. Apparatus as claimed in claim 1 wherein said power is 0.5-20 W/cm2.

3. Apparatus as claimed in claim 1 wherein said power is 0.5-5 W/cm2.

4. Apparatus as claimed in claim 1 wherein said source includes a broadband optical radiation source, and a filter through which radiation from said broadband source is passed.

5. Apparatus as claimed in claim 4 wherein said filter includes a water filter to at least attenuate wavelengths from said broadband source which are selectively absorbed by water.

6. Apparatus as claimed in claim 5 wherein said water filter includes chilled water flowing between said broadband source and the patient'"'"'s body, said flowing chilled water also functioning as part of said mechanism for cooling.

7. Apparatus as claimed in claim 4 wherein said cooling mechanism also cools said filter.

8. Apparatus as claimed in claim 4 including a mechanism for removing heat from said filter.

9. Apparatus as claimed in claim 1 wherein said source includes optics for shaping radiation to be delivered to said selected region.

10. Apparatus as claimed in claim 1 wherein said source is at least primarily at one or more wavelengths between about 600 nm and about 1850 nm.

11. Apparatus as claimed in claim 10 wherein said source is at least primarily at one or more wavelengths between about 800 nm and about 1350 nm.

12. Apparatus as claimed in claim 10 wherein said source is at least primarily at one or more wavelengths between about 1050 nm and about 1250 nm.

13. Apparatus as claimed in claim 1 wherein said optical radiation source and said mechanism are concurrently operated for a period of at least two seconds.

14. Apparatus as claimed in claim 13 wherein said optical radiation source and said mechanism are concurrently operated for a period of at least five seconds.

15. Apparatus as claimed in claim 1 wherein said optical radiation source and said mechanism are concurrently operated for a period of between about two seconds and two hours.

16. Apparatus as claimed in claim 13 including a precooling mechanism which cools tissue above said selected region prior to the concurrent operation of said source and said cooling mechanism.

17. Apparatus as claimed in claim 16 wherein said cooling mechanism and said precooling mechanism are the same mechanism.

18. Apparatus as claimed in claim 16 wherein said optical radiation power and said period of concurrent operation vary dependent on whether said precooling mechanism is operated.

19. Apparatus as claimed in claim 1 wherein parameters for said optical radiation source and for said cooling mechanism are selected to achieve a selected temperature as indicated by equation 10 at a selected depth z max determined by equation 11.

20. Apparatus as claimed in claim 19 wherein the minimum treatment time for the apparatus is determined in accordance with equation 12.

21. Apparatus as claimed in claim 1 wherein said apparatus is an apparatus for fat reduction, said radiation heating subdermal fat tissue.

22. Apparatus as claimed in claim 1 including a mechanism for stimulating tissue in said selected region.

23. Apparatus as claimed in claim 22 wherein said mechanism for providing stimulation is at least one of a mechanical stimulator, acoustic stimulator and an electrical stimulator.

24. Apparatus as claimed in claim 1 wherein said selected region contains at least one hair bulb, and wherein parameters for said apparatus, including said source, are selected to slowly damage said bulb.

25. A method for treating at least a selected region at depth of a patient'"'"'s body while protecting tissue above the selected region, comprising:

(a) selectively delivering optical radiation at a power between approximately 0.2 and 50 W/cm2 to the patient'"'"'s body above said selected region, said power varying at least in part as a function of the depth of said selected region, said optical radiation being applied to said selected region for at least approximately 2 seconds; and

(b) concurrently cooling patient tissue above said selected region to a temperature below that of the selected region.

26. A method as claimed in claim 25 wherein said power is 0.5-20 W/cm2.

27. A method as claimed in claim 25 wherein said power is 0.5-5 W/cm2.

28. A method as claimed in claim 25 wherein step (a) includes generating broad band optical radiation, and filtering said broad band radiation before delivering it to said patient'"'"'s body.

29. A method as claimed in claim 25 wherein said method is a method for fat reduction, said radiation heating subdermal fat tissue.

30. A method as claimed in claim 25 wherein said method is a method for performing therapy on at least one of subdermal muscle, ligament and bone, said radiation causing heating of such muscle/ligament/bone and of tissue in the area thereof to at least increase blood flow in such area.

31. A method as claimed in claim 25 wherein said method is a method for treating a selected unwanted growth, said radiation heating said growth sufficiently to cause the destruction thereof.

32. The method of claim 25, wherein the electromagnetic energy is at least primarily at one or more wavelengths between about 600 nm and about 1850 nm.

33. The method of claim 32, wherein the electromagnetic energy is at least primarily at one or more wavelengths between about 800 nm and about 13500 nm.

34. The method of claim 32 wherein the electromagnetic energy is at least primarily at one or more wavelengths between about 1050 nm and about 1250 nm.

35. The method of claim 25 wherein step (a) and step (b) are performed concurrently for a period of at least two seconds.

36. The method of claim 35 wherein step (a) and step (b) are performed concurrently for a period of at least five seconds.

37. The method of claim 25 wherein step (a) and step (b) are performed concurrently for a period of between about two seconds and about two hours.

38. The method of claim 25 including the step of precooling tissue above said selected region.

39. The method of claim 38 wherein said optical radiation power and said period of concurrent operation vary dependent on whether said precooling step is performed.

40. The method of claim 25 wherein said selected region is heated during step (a).

41. The method of claim 25 wherein parameters for said optical radiation and for said cooling are selected to achieve a selected temperature as indicated by equation 10 at a selected depth z max determined by equation 11.

42. The method of claim 41 wherein the minimum treatment time for the method is determined in accordance with equation 12.

43. The method of claim 25 wherein said method is a method for fat reduction, subdermal fat tissue being heated during step (a).

44. The method of claim 25 including the step of stimulating tissue in said selected region.

45. The method of claim 44 wherein said step of providing stimulation provides at least one of mechanical stimulation, acoustic stimulation and electrical stimulation.

46. The method of claim 25 wherein said selected region contains at least one hair bulb, and wherein parameters for said method, including said radiation, are selected to slowly damage said bulb.

47. Apparatus for treating at least a selected region at depth of a patient while protecting tissue above the selected region, comprising:

an optical radiation source for delivering radiation at a power of between 0.2-50 W/cm² to the patient'"'"'s skin for a duration between two seconds and two hours, both said power and said duration increasing with increased depth for said selected region; and

a cooling mechanism for cooling tissue above said selected region to a temperature below that of said selected region.

48. Apparatus for treating at least a selected region at depth of a patient while protecting tissue above the selected region, comprising:

an optical radiation source for delivering radiation of a wavelength between 600 nm and 1850 nm and at a power of between 0.2-50 W/cm² to the patient'"'"'s skin, the wavelength and the power both varying as a function of the depth of the selected region; and

a cooling mechanism for cooling tissue above said selected region to a temperature below that of said selected region.

49. Apparatus for treating at least a selected region at depth of a patient while protecting tissue above the selected region, comprising:

an optical radiation source for delivering radiation of a wavelength between about 600 nm and about 18500 nm, at a power of between 0.2-50 W/cm² to the patient'"'"'s skin for a duration between two seconds and two hours, the wavelength, duration and power all varying as a function of the depth of the selected region; and

a cooling mechanism for cooling tissue above said selected region to a temperature below that of said selected region.

50. A method for treating at least a selected region at depth of a patient'"'"'s body while protecting tissue above the selected region, comprising:

(a) selectively delivering radiation at a power between approximately 0.2 and 50 W/cm2 to the patient'"'"'s body above said selected region for a duration of two seconds to two hours, both said power and said duration varying with the depth of said selected region; and

(b) concurrently cooling patient tissue above said selected region to a temperature below that of the selected region.

51. A method for treating at least a selected region at depth of a patient'"'"'s body while protecting tissue above the selected region, comprising:

(a) selectively delivering radiation of a wavelength between about 600 nm and about 1850 nm and at a power between approximately 0.2 and 50 W/cm2 to the patient'"'"'s body above said selected region, both said power and wavelength varying as a function of the depth of said selected region; and

(b) concurrently cooling patient tissue above said selected region to a temperature below that of the selected region.

52. A method for treating at least a selected region at depth of a patient'"'"'s body while protecting tissue above the selected region, comprising:

(a) selectively delivering radiation to the patient'"'"'s body above said selected region to heat the region;

(b) concurrently cooling patient tissue above said selected region to a temperature below that of the selected region; and

(c) applying at least one of mechanical, acoustic and electrical stimulation to said region.

53. A method for treating at least a selected region at depth of a patient'"'"'s body while protecting tissue above the selected region, comprising:

(a) selectively delivering radiation to the patient'"'"'s body above said selected region to heat the region, said radiation being selected so as not to be scattered or absorbed by tissue above said selected region sufficiently to prevent sufficient radiation from reaching the selected region to effect a desired treatment; and

(b) concurrently cooling patient tissue above said selected region to a temperature below that of the selected region.

54. A method as claimed in claim 53 wherein said selected region contains subdermal fat;

and

wherein said radiation at least includes at least one wavelength selectively absorbed by fat.

55. A method for hair management comprising:

(a) selectively delivering radiation to the patient'"'"'s body above a region of subdermal fat containing a bulb for a hair to be removed to heat the region and thus the hair bulb, resulting in damage thereto; and

(b) concurrently cooling patient tissue above said region to a temperature below that of the region.