Selective photothermolysis of cutaneous pigmentation by Q-switched Nd: YAG laser pulses at 1064, 532, and 355 nm.

摘要: Exposure of skin to nanosecond-domain laser pulses affects the pigmentary system by a process called selective photothermolysis, in which melanosomes and pigmented cells are preferentially altered. Due broad absorption spectrum melanin, this effect may occur with wavelengths that penetrate vastly different depths within tissue, potentially producing biologic responses. The effects single near-ultraviolet (355 nm), visible (532 near infrared (1064 nm) 10-12 nsec duration were determined guinea pig using gross, histologic, electron microscopic observations. Threshold response was transient immediate ash-white discoloration, requiring 0.11, 0.20, 1.0 J/cm2, at 355, 532, 1064 nm, respectively. At each wavelength, ruptured keratinocytes melanocytes, cytoplasmic nuclear alterations. Delayed epidermal depigmentation occurred, followed gradual repigmentation. Deep follicular altered only 532 produced permanent leukotrichia. action for threshold consistent mechanisms implied photothermolysis. These data be useful consideration treatment cutaneous pigmentation abnormalities or unwanted pigmentation, both.