Comparative Histological Studies of the Tunable Dye (at 577 nm) Laser and Argon Laser: The Specific Vascular Effects of the Dye Laser

Tunable Pulsed Dye Laser for the Treatment of Benign Cutaneous Vascular Ectasia

“…The pulse width of 360 ps was preferred to the continuous-wave mode of the argon and CO, lasers, because pulses shorter than 2-3 ms confine heat inside vessels. Whereas ar gon and CO, lasers nonselectively destroy vessels in the superficial dermis and epider mis [6], the tunable dye laser selectively de stroys ectatic vessels up to 1 mm into the der mis. The selective effect on vascular struc tures minimizes damage to the surrounding normal dermis, which explains the absence of scars observed even after several consecu tive irradiations of the same area.…”

“…It has been theoretically predicted [5] and confirmed in normal human skin [6] that the destruction of blood vessels without in juring surrounding normal dermis can be achieved by carefully chosen wavelength (577 nm), pulse duration (360 ps) and dose (energy/area). This is called selective pho tothermolysis of blood vessels and has been used successfully in the treatment of port wine stain with the Candela tunable dye laser [7,8], In those studies, all patients had a beneficial response without scarring.…”

Principles of Light-Skin Interactions

“…At about 120°C, thrombosis of the blood vessels and necrotizing vasculitis have been demonstrated. [47][48][49] The Arrhenius model demonstrates that the rate of denaturation rises exponentially with temperature, thus the accumulation of denatured material also rises proportionally with time. 50 This accounts for the boundaries of dermal coagulation and laser-induced thermal injury.…”

Laser Treatment of Port Wine Stains

“…In the range of the argon laser, extinction in melanin is rela tively high, in hemoglobin relatively low, resulting in a relatively unspecific action of the argon laser. In contrast, at 577 nm extinction in melanin decreased and there is a peak in hemoglobin extinction, resulting in a much higher vessel specificity of the dye laser at 577 nm [19]. Selective coagulation of ectatic port wine stain vessels by dye laser irradiations could be demon strated [20].…”