Picosecond laser apparatus and methods for treating target tissues with same
Apparatuses and methods are disclosed for applying laser energy having desired pulse characteristics, including a sufficiently short duration and/or a sufficiently high energy for the photomechanical treatment of skin pigmentations and pigmented lesions, both naturally-occurring (e.g., birthmarks), as well as artificial (e.g., tattoos). The laser energy may be generated with an apparatus having a resonator with the capability of switching between a modelocked pulse operating mode and an amplification operating mode. The operating modes are carried out through the application of a time-dependent bias voltage, having waveforms as described herein, to an electro-optical device positioned along the optical axis of the resonator.
1. A method of treating a target tissue comprising one or more scars, the method comprising:
generating, using a laser source, an output beam having a subnanosecond pulse duration;
modifying the output beam, using an optical system, to provide a photomechanically disruptive treatment beam;
directing the photomechanically disruptive treatment beam to the one or more scars, wherein the one or more scars is one or more atrophic scars;
photomechanically disrupting the one or more scars; and
decreasing visible appearance of the one or more scars in response to the treatment beam.
2. The method of claim 1 wherein decreasing visible appearance of the one or more scars comprises decreasing scar tissue volume.
3. The method of claim 2 wherein decreasing scar tissue volume comprises suppressing fibroblast proliferation.
4. The method of claim 2 wherein decreasing scar tissue volume comprises suppressing collagen expression.
5. The method of claim 1 wherein the one or more scars are in a treatment region, further comprising applying a corticosteroid to the treatment region.
6. The method of claim 1 wherein the one or more scars are in a treatment region, further comprising applying a cytotoxic agent to the treatment region.
7. The method of claim 1 wherein the one or more scars are in a treatment region, wherein decreasing visible appearance of the one or more scars comprises evening out tissue depth in treatment region.
8. The method of claim 1 , wherein the treatment beam has a non-uniform profile.
9. The method of claim 8 , wherein the non-uniform profile comprises a first energy distribution and a second energy distribution.
10. The method of claim 8 , wherein the non-uniform profile comprises a plurality of regions of relatively high energy per unit area dispersed within a substantially uniform background region of relatively low energy per unit area.
11. The method of claim 9 further comprising increasing temperature of a first region of scar tissue to a first temperature T 1 and increasing or maintaining temperature of a second region of scar tissue to a second temperature T 2 using the non-uniform distribution of the treatment beam.
12. The method of claim 11 wherein T 1 ranges from about 45 degrees Celsius to about 50 degrees Celsius.
13. The method of claim 1 wherein the treatment beam has a non-uniform profile comprising a plurality of regions of relatively high energy per unit area dispersed within a substantially uniform background region of relatively low energy per unit area.
14. The method of claim 13 , wherein the target tissue comprising one or more scars comprises a dermal layer and an epidermal layer further comprising increasing temperature of at least one of the dermal layer and the epidermal of the one or more scars to a first temperature T 1 and increasing or maintaining temperature of a second region of scar tissue to a second temperature T 2 using the non-uniform distribution of the treatment beam.
15. The method of claim 14 wherein T 1 ranges from about 45 degrees Celsius to about 50 degrees Celsius.
16. The method of claim 14 wherein T 1 is approximately 70 degrees Celsius or greater.
17. A method of treating a target tissue comprising one or more scars, the method comprising:
generating, using a laser source, an output beam having a subnanosecond pulse duration;
modifying the output beam, using an optical system, to provide a photomechanically disruptive treatment beam;
directing the photomechanically disruptive treatment beam to the one or more scars, wherein the one or more scars is one or more hypertrophic scars;
photomechanically disrupting the one or more scars; and
decreasing visible appearance of the one or more scars in response to the treatment beam.
18. The method of claim 17 wherein decreasing visible appearance of the one or more scars comprises decreasing scar tissue volume.
19. The method of claim 18 wherein decreasing scar tissue volume comprises suppressing fibroblast proliferation.
20. The method of claim 18 wherein decreasing scar tissue volume comprises suppressing collagen expression.
21. The method of claim 17 wherein the one or more scars are in a treatment region, further comprising applying a corticosteroid to the treatment region.
22. The method of claim 17 wherein the one or more scars are in a treatment region, further comprising applying a cytotoxic agent to the treatment region.
23. The method of claim 17 wherein the one or more scars are in a treatment region, wherein decreasing visible appearance of the one or more scars comprises evening out tissue depth in treatment region.
24. The method of claim 17 , wherein the treatment beam has a non-uniform profile.
25. The method of claim 24 , wherein the non-uniform profile comprises a first energy distribution and a second energy distribution.
26. The method of claim 24 , wherein the non-uniform profile comprises a plurality of regions of relatively high energy per unit area dispersed within a substantially uniform background region of relatively low energy per unit area.
27. The method of claim 25 further comprising increasing temperature of a first region of scar tissue to a first temperature T 1 and increasing or maintaining temperature of a second region of scar tissue to a second temperature T 2 using the non-uniform distribution of the treatment beam.
28. The method of claim 27 wherein T 1 ranges from about 45 degrees Celsius to about 50 degrees Celsius.
29. The method of claim 17 wherein the treatment beam has a non-uniform profile comprising a plurality of regions of relatively high energy per unit area dispersed within a substantially uniform background region of relatively low energy per unit area.
30. The method of claim 29 , wherein the target tissue comprising one or more scars comprises a dermal layer and an epidermal layer further comprising increasing temperature of at least one of the dermal layer and the epidermal of the one or more scars to a first temperature T 1 and increasing or maintaining temperature of a second region of scar tissue to a second temperature T 2 using the non-uniform distribution of the treatment beam.
31. The method of claim 30 wherein T 1 ranges from about 45 degrees Celsius to about 50 degrees Celsius.
32. The method of claim 30 wherein T 1 is approximately 70 degrees Celsius or greater.