Effect of dye laser pulse duration on selective cutaneous vascular injury

Journal Article · Sat Nov 01 00:00:00 EST 1986 · J. Invest. Dermatol.; (United States)

DOI:https://doi.org/10.1111/1523-1747.ep12456368· OSTI ID:6846364

Garden, J M; Tan, O T; Kerschmann, R; Boll, J; Furumoto, H; Anderson, R R; Parrish, J A

The pulsed dye laser at 577 nm, a wavelength well absorbed by oxyhemoglobin, causes highly selective thermal injury to cutaneous blood vessels. Confinement of thermal damage to microvessels is, in theory, related to the laser exposure time (pulsewidth) on selective vascular injury. This study investigates the effect of 577 nm dye laser pulsewidth on selective vascular injury. Nine Caucasian, normal volunteers received 577 nm dye laser exposures at pulsewidths of 1.5-350 microseconds to their skin. Clinical purpura threshold exposure doses were determined in each volunteer, and biopsies of threshold and suprathreshold doses were examined in each volunteer. The laser exposure dose required to produce purpura increased as pulsewidth increased in all 9 subjects (p less than 0.001). This finding corresponds to laser pulsewidths equal to or exceeding the thermal relaxation times for dermal blood vessels. Histologically, vessel damage was selectively, but qualitatively, different for short vs long pulsewidths. Pulsewidths shorter than 20 microseconds caused vessel wall fragmentation and hemorrhage, whereas longer pulsewidths caused no significant hemorrhage. The purpura noted clinically appears to be due to a coagulum of intralumenal denatured erythrocytes. At 24 h, there was marked vessel wall necrosis at all pulsewidths. The short pulsewidths may cause erythrocyte vaporization, rapid thermal expansion, and mechanical vessel rupture with hemorrhage. Long pulsewidths appear to cause thermal denaturation with less mechanical vessel damage. The selective, nonhemorrhagic, vascular necrosis caused by the long-pulsewidth dye laser may lead to a more desirable clinical outcome in the therapy of blood vessel disease processes.

• Research Organization: Northwestern Univ., Chicago, IL
• OSTI ID: 6846364
• Journal Information: J. Invest. Dermatol.; (United States), Vol. 5
• Country of Publication: United States
• Language: English

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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
DYE LASERS
BIOLOGICAL EFFECTS
VEINS
TEMPERATURE EFFECTS
COLLAGEN
EPIDERMIS
MAN
PURPURA
SKIN
ANIMAL TISSUES
ANIMALS
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LASERS
LIQUID LASERS
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TISSUES
VERTEBRATES
560400* - Other Environmental Pollutant Effects