Putative photoacoustic damage in skin induced by pulsed ArF excimer laser

Journal Article · Sun May 01 00:00:00 EDT 1988 · J. Invest. Dermatol.; (United States)

DOI:https://doi.org/10.1111/1523-1747.ep12560953· OSTI ID:7150472

Watanabe, S; Flotte, T J; McAuliffe, D J; Jacques, S L

Argon-fluoride excimer laser ablation of guinea pig stratum corneum causes deeper tissue damage than expected for thermal or photochemical mechanisms, suggesting that photoacoustic waves have a role in tissue damage. Laser irradiation (193 nm, 14-ns pulse) at two different radiant exposures, 62 and 156 mJ/cm2 per pulse, was used to ablate the 15-microns-thick stratum corneum of the skin. Light and electron microscopy of immediate biopsies demonstrated damage to fibroblasts as deep as 88 and 220 microns, respectively, below the ablation site. These depths are far in excess of the optical penetration depth of 193-nm light (1/e depth = 1.5 micron). The damage is unlikely to be due to a photochemical mechanism because (a) the photons will not penetrate to these depths, (b) it is a long distance for toxic photoproducts to diffuse, and (c) damage is proportional to laser pulse intensity and not the total dose that accumulates in the residual tissue; therefore, reciprocity does not hold. Damage due to a thermal mechanism is not expected because there is not sufficient energy deposited in the tissue to cause significant heating at such depths. The damage is most likely due to a photoacoustic mechanism because (a) photoacoustic waves can propagate deep into tissue, (b) the depth of damage increases with increasing laser pulse intensity rather than with increasing total residual energy, and (c) the effects are immediate. These effects should be considered in the evaluation of short pulse, high peak power laser-tissue interactions.

• Research Organization: Massachusetts General Hospital, Boston (USA)
• OSTI ID: 7150472
• Journal Information: J. Invest. Dermatol.; (United States), Vol. 90:5
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
LASER RADIATION
BIOLOGICAL EFFECTS
SKIN
INJURIES
ARGON
ELECTRON MICROSCOPY
FLUORIDES
GAS LASERS
BODY
ELECTROMAGNETIC RADIATION
ELEMENTS
FLUIDS
FLUORINE COMPOUNDS
GASES
HALIDES
HALOGEN COMPOUNDS
LASERS
MICROSCOPY
NONMETALS
ORGANS
RADIATIONS
RARE GASES
560400* - Other Environmental Pollutant Effects