Dynamic cooling of tissue for radiation treatment

• US 20010009997A1
• Filed: 01/18/2001
• Published: 07/26/2001
• Est. Priority Date: 01/29/1999
• Status: Active Grant

• Current Assignee: Candela Corporation
• Original Assignee: Candela Corporation
• Inventors: Durkin, Anthony J., Pope, Karl, Hsia, James C.
• Granted Patent: US 6,514,244 B2
• Time in Patent Office: Days
• US Class Current: 606/9
• CPC Class Codes: A61B 18/0218 with open-end cryogenic probe, e.g. for spraying fluid directly on tissue or via a tissue-contacting porous tip
• CPC Class Codes: A61B 18/203 applying laser energy to the outside of the body
• CPC Class Codes: A61B 2018/00017 with gas
• CPC Class Codes: A61B 2018/00023 closed, i.e. without wound contact by the fluid
• CPC Class Codes: A61B 2018/00029 open
• CPC Class Codes: A61B 2018/00452 Skin

Abstract

The present invention features various methods and systems for performing radiation treatment of skin in connection with dynamic cooling of tissue, while minimizing or preventing occurrence of light flash during the treatment.

Claims

1. A method for performing radiation treatment of skin having an epidermal tissue region adjacent a dermal tissue region, the method comprising:

a) cooling the epidermal tissue region by applying a cryogenic fluid to the epidermal tissue region;

b) directing a gas flow in general direction of the epidermal tissue region to remove at least a portion of the cryogenic fluid applied to the epidermal tissue region; and

c) irradiating the skin with a radiation beam to treat the dermal tissue region subsequent to removing at least a portion of the cryogenic fluid to prevent a light flash during the irradiation step.

2. The method of

claim 1

wherein step b) comprises directing a non-reactive gas flow in the general direction of the epidermal tissue region.

3. The method of

claim 2

wherein step b) comprises blowing air in the general direction of the epidermal tissue region.

4. The method of

claim 2

wherein the non-reactive gas comprises nitrogen.

5. The method of

claim 1

wherein step b) comprises directing a gas flow in the general direction of the epidermal tissue region prior to and during application of the cryogenic fluid.

6. The method of

claim 1

wherein step c) comprises irradiating the skin for between about 5 milliseconds and 500 milliseconds after applying the cryogenic fluid to the epidermal tissue region.

7. The method of

claim 1

wherein step a) comprises applying a first pulse of cryogenic fluid to the epidermal tissue region for a first time period and waiting a delay period of a predetermined time interval before applying a second pulse of cryogenic fluid to the epidermal tissue region for a second time period.

8. The method of

claim 7

wherein the delay period is in a range from about 10 milliseconds to about 500 milliseconds.

9. The method of

claim 7

wherein the first time period comprises from about 20 milliseconds to 100 milliseconds and the second time period comprises from about 5 milliseconds to 20 milliseconds.

10. The method of

claim 1

wherein step a) comprises applying a cryogenic liquid and step b) comprises removing a cryogenic vapor formed through evaporation of the cryogenic liquid.

11. The method of

claim 1

wherein step b) comprises removing a plurality of contaminants over an outer surface of the epidermal tissue region.

12. The method of

claim 1

wherein step b) comprises directing a gas flow at a rate of greater than about 10 liters per minute

13. The method of

claim 1

further comprising pre-cooling the gas flow to a temperature below about 20°

C.

14. The method of

claim 1

wherein step a) comprises applying of cryogen comprising a fluorocarbon compound wherein a ratio of fluorine to fluorine and hydrogen is equal to or greater than about 0.75.

15. The method of

claim 14

wherein the fluorocarbon compound is selected from a group consisting of:

tetrafluromethane;

hexafluoroethane;

octafluoropropane;

chlorotrifluromethane;

chloropentafluoroethane;

dichlorodifluoromethane;

1,2-dichlorotetrafluoroethane;

1,1,1,2,3,3,3,-heptafluoropropane;

pentafluoroethane;

2-chloro-1,1,1,2-tetrafluoroethane;

trifluoromethane;

1,1,1,2,3,3-hexafluoropropane; and

2,2-dichloro-1,1,1-trifluoroethane

16. The method of

claim 1

wherein step c) comprises irradiating the dermal tissue region to remove a hair.

17. The method of

claim 1

wherein step c) comprises irradiating with a laser light.

18. The method of

claim 1

further comprising d) postcooling the epidermal tissue region by applying a cryogenic fluid to the epidermal tissue region after the irradiation step.

19. A method of performing radiation treatment of skin having an epidermal tissue region adjacent a dermal tissue region, the method comprising:

a) applying a first pulse of cryogenic fluid to the epidermal tissue region for a first time period;

b) waiting a delay period of a predetermined time interval before applying a second pulse of cryogenic liquid to the epidermal tissue region for a second time period, the delay period being sufficient to allow the first pulse of cryogenic fluid to cool the epidermal tissue region to reach a desired temperature; and

c) irradiating the skin to treat the dermal tissue region during or immediately after application of the second pulse of cryogenic liquid, thereby preventing a light flash during the irradiation step.

20. The method of

claim 19

wherein step a) comprises spraying a cryogenic liquid to the epidermal tissue region for a time period in a range from about 10 milliseconds to 150 milliseconds.

21. The method of

claim 19

wherein step b) comprises spraying a cryogenic liquid to the epidermal tissue region for a time period in a range from about 5 milliseconds to about 20 milliseconds.

22. The method of

claim 19

wherein the delay period is in a range from about 10 milliseconds to about 500 milliseconds.

23. The method of

claim 19

wherein step c) comprising irradiating the skin within 5 milliseconds of applying the second pulse of cryogenic liquid.

24. The method of

claim 19

wherein step a) comprises applying a first pulse of cryogenic liquid comprising a fluorocarbon compound wherein a ratio of fluorine to fluorine and hydrogen is equal to or greater than about 0.75;

and step b) comprises applying a second pulse of cryogenic liquid comprising the fluorocarbon compound.

25. The method of

claim 24

wherein the fluorocarbon compound comprises a compound selected from a group consisting of:

tetrafluoromethane;

hexafluoroethane;

octafluoropropane;

chlorotrifluromethane;

chloropentafluoroethane;

dichlorodifluoromethane;

1,2-dichlorotetrafluoroethane;

1,1,1,2,3,3,3,-heptafluoropropane;

pentafluoroethane;

2-chloro-1,1,1,2-tetrafluoroethane;

trifluoromethane;

1,1,1,2,3,3-hexafluoropropane; and

2,2-dichloro-1,1,1-trifluoroethane.

26. The method of

claim 19

wherein step c) comprises irradiating the dermal tissue to remove hair.

27. The method of

claim 19

wherein step c) comprises irradiating with a laser light.

28. An apparatus having a laser source for performing a radiation treatment of skin having an epidermal tissue region adjacent a dermal tissue region, the apparatus comprising:

a) a first fluid delivery device for delivering a cryogen to the epidermal tissue region;

b) a device for delivering radiation to the skin to treat the dermal tissue region; and

c) a second fluid delivery device for delivering a gas flow in general direction of the epidermal tissue region to remove a portion of the cryogen delivered to the epidermal tissue region.

29. The apparatus of

claim 28

wherein the second fluid delivery device surrounds the optical device.

30. The apparatus of

claim 28

wherein the second fluid delivery device is substantially collinear with the first fluid delivery device.

31. The apparatus of

claim 28

wherein the second fluid delivery device surrounds the first fluid delivery device.

32. The apparatus of

claim 28

wherein the second fluid delivery device comprises a plurality of passageways substantially surrounding the optical device.

33. The apparatus of

claim 28

further comprising a body, and wherein the second fluid delivery device comprises an inlet for introducing the gas to the body and an outlet for removing the gas from the body, such that the gas entering the body through the inlet circulates within the body.

34. A handpiece attachable to a laser for performing laser treatment of skin having an epidermal tissue region adjacent a dermal tissue region, the handpiece comprising:

a body;

an optical device disposed inside the body for delivering a light beam from the laser to the skin to treat the dermal tissue region;

a valve disposed inside the body for delivering a cryogen to the epidermal tissue region; and

a fluid delivery device disposed inside the body for delivering a gas flow in general direction of the epidermal tissue region to remove at least a portion of the cryogen delivered to the epidermal tissue region.

35. The handpiece of

claim 34

wherein the fluid delivery device substantially surrounds the optical device.

36. The handpiece of

claim 34

wherein the fluid delivery device comprises a plurality of passageways substantially surrounding the optical device.

37. The handpiece of

claim 34

wherein the fluid delivery device comprises an inlet for introducing the gas to the body and an outlet for removing the gas from the body, such that the gas entering the body circulates within the body.