Lasers in Surgery and Medicine · 1994 · 145 citations · 28 references
Water is the primary tissue chromophore in the midinfrared, and its absorption depends on temperature and pressure, which rise rapidly during an ablative laser pulse. The study introduces an ablation model that incorporates dynamic changes in water absorption based on Beer's Law. The model accounts for temperature and pressure‑induced variations in the absorption coefficient during high‑irradiance laser pulses. Dynamic absorption of water can change by up to two orders of magnitude during a pulse, causing the model to predict deeper Er:YAG cuts than Er:YSGG cuts, and in vitro skin ablation confirms that these dynamic optical properties must be considered for laser system design and regulation. © 1994 Wiley‑Liss, Inc.
Abstract Water is a primary tissue chromophore in the midinfrared. Absorption of midinfrared radiation by water is a function of temperature and pressure, both of which rise rapidly during an ablative laser pulse. Data show that the absorption coefficient of water changes, by as much as two orders of magnitude, during a high‐irradiance laser pulse. We present an ablation model that is fundamentally based upon Beer's Law but considers changes in the absorption coefficient. The model predicts that Er:YAG laser cuts will be deeper than Er:YSGG laser cuts; an opposite prediction would be made based upon the static, low‐intensity absorption coefficient of water. The results of in vitro ablation of skin confirm that the dynamic optical properties of tissue need to be considered in the understanding of laser ablation as well as the design, manufacture, use, and regulation of clinical laser systems. © 1994 Wiley‐Liss, Inc.
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Ablation of Polymers and Biological Tissue by Ultraviolet Lasers
R. Srinivasan · Science · 1986 · 560 citations