DYNAMIC EPIDERMAL COOLING IN CONJUNCTION WITH LASER-INDUCED PHOTOTHERMOLYSIS OF PORT-WINE STAIN BLOOD-VESSELS

When a cryogen spurt is applied to the shin surface for an appropriate ly short period of time (on the order of tens of milliseconds), the sp atial distribution of cooling remains localized in the normal overlyin g epidermis, while leaving the temperature of the deeper port wine sta in (PWS) blood vessels unchanged. Furthermore, cooling continues after pulsed laser exposure as cryogen remaining on the surface evaporates and removes heat deposited by light absorption in epidermal melanin. A n additional advantage of dynamic cooling is a reduction in the level of pain and discomfort associated with flashlamp-pumped pulsed dye las er therapy of PWS. Preliminary clinical studies and supporting theoret ical calculations demonstrate the feasibility of selective epidermal c ooling while achieving photothermolysis of blood vessels during pulsed laser treatment of PWS. (C) 1996 Wiley-Liss, Inc.