Putative photoacoustic damage in skin induced by pulsed ArF excimer laser.
Putative photoacoustic damage in skin induced by pulsed ArF excimer laser.
复制标题
脉冲 ArF 准分子激光诱导皮肤的假定光声损伤。
DOI：
10.1111/1523-1747.ep12560953
复制
发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Jacques,SL
中科院分区：
文献类型：
--
作者：
Watanabe,S;Flotte,TJ;McAuliffe,DJ;Jacques,SL
氟化物准分子激光消融豚鼠角质层引起比热或光化学机制所预期的更深的组织损伤，这表明光声波在组织损伤中起作用。激光照射波长193 nm，脉冲14 ns，照射剂量分别为62和156mJ/cm2，消融15μm厚的皮肤角质层。即刻活检的光镜和电子显微镜显示成纤维细胞损伤深度分别为88和220μm，位于消融部位下方。这些深度远远超过了193nm光的光学穿透深度(1/e深度=1.5μm)。损伤不太可能是由于光化学机制造成的，因为(A)光子不会穿透到这些深度，(B)有毒光产物扩散的距离很长，(C)损伤与激光脉冲强度成正比，而不是残留组织中积累的总剂量；因此，互易性不成立。由于没有足够的能量沉积在组织中，在这样的深度引起显著的加热，因此不会预期由于热机制而造成的损害。损伤很可能是由于光声机制造成的，因为(A)光声波可以传播到组织的深处，(B)损伤的深度随着激光脉冲强度的增加而增加，而不是随着总剩余能量的增加而增加，以及(C)影响是即时的。在评估短脉冲、高峰值功率激光与组织的相互作用时，应考虑这些影响。
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/cm2per pulse, was used to ablate the 15-μm-thick stratum corneum of the skin. Light and electron microscopy of immediate biopsies demonstrated damage to fibroblasts as deep as 88 and 220 μm, 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 μm). 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.