Hye-Jin Ahn
Kyung Hee University, Seoul, Korea
Title: Interaction of skin to fractional picosecond laser in Asian
Biography
Biography: Hye-Jin Ahn
Abstract
Picosecond laser accepted by FDA for tattoo removal and pigment at first. By aid of micro lens array(MLA), more focused laser beam irradiation could be irradiate on the skin. Therefore, the purpose of laser application is widen to scar, and rejuvenation. In this study, we evaluated the fractionated picosecond laser to skin interaction in subjects of Fitzpatrick skin type III and IV.
We used 1064-nm picosecond laser with MLA with a spot size of 4 mm, fluence of 2.2~2.8 J/cm2, and pulse width of 450 picoseconds in vivo. Total 3 subjects in skin type III and IV participated in the study. After treatment immediately, biopsies were performed. Hematoxylin and eosin and immunohistochemical stain for CD31, D2-40. Histology revealed the multiple microscopic cavities formed by coagulation necrosis of keratinocytes induced by thermal damage in epidermis. A few cavities in upper dermis were proved to be dilated venules and lymphatics, confirmed by CD31 and D2-40 immunohistochemical stain and no definite laser induced cavities were observed. Thermal denaturation of dermal collagen was not clearly demonstrated. Perivascular infiltration of inflammatory cells were not noted.
In Asian skin, after fractional picosecond laser, laser induced coagulation damage produced the vacuole in epidermis and dilatation of venules and lymphatics in upper dermis. Further research is needed on how these changes results in skin rejuvenation.