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COMPARATIVE STUDIES OF FEMTOSECOND TO MICROSECOND LASER PULSES ON SELECTIVE PIGMENTED CELL INJURY IN SKIN
Author(s) -
Watanabe Shinichi ,
Anderson R. Rox ,
Brorson Stuart ,
Dalickas Gail ,
Fujimoto James G.,
Flotte Thomas J.
Publication year - 1991
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1991.tb09889.x
Subject(s) - melanosome , microsecond , laser , femtosecond , pulse (music) , chemistry , optics , melanin , physics , biochemistry , detector
— —Threshold radiant exposures for grossly apparent immediate whitening and ultrastructural alterations of melanosomes in black guinea pig skin were determined for a series of red visible laser pulses ranging from 4 × 10 −4 to 6.5 × 10 −14 s. Threshold exposures for melanosomal injury were found to be independent of pulsewidth when the pulsewidths were below the estimated thermal relaxation time of melanosomes. Threshold radiant exposures for melanosomal injury were found to increase when the pulsewidths were approximately equal to or above the thermal relaxation time of melanosomes. At longer pulse durations, fracturing of melanosomes was not observed despite the longer exposures necessary for injury. Instead, perimelanosomal vacuoles were noted. These findings are consistent with the theory of selective photothermolysis and provide evidence for the thermal initiation of melanosomal disruption.