Multiple-pulse skin damage thresholds at 1070 NM Available to Purchase

As solid-state laser technology continues to mature, high-energy lasers operating in the near-infrared (NIR) band are increasingly being utilized in manufacturing, medical, and military applications. Guidelines for the safe use of these systems have been established as formulations of maximum permissible exposure (MPE) limits for a given set of laser parameters, based on past experimental studies of exposure thresholds causing injury to the skin and eyes. However, in the case of skin, these formulations do not take into account the pulse characteristics of the exposure and only utilize the total exposure duration when calculating the MPE. The purpose of this study was to characterize the skin response to multiple-pulsed high-energy laser exposure at the NIR wavelength of 1070 nm, at a constant beam diameter of 1 cm, and using anesthetized Yucatan mini-pig subjects. A constant total laser-on time was explored as single- and multiple-pulse sequences. Multiple-pulse exposures had identical individual pulse durations, and different duty cycles were employed in order to characterize the effect of variable thermal additivity. Skin damage was quantified by the minimally visible lesion (MVL) metric as judged by a plurality of three observers at the 24-hour interval post-exposure. Injury thresholds for all exposure conditions were calculated as the median effective dose (ED₅₀), based on varying laser power across subjects. The results of this study will provide a quantitative basis for the incorporation of multiple-pulsed laser exposure into existing standards and augment data contained in the existing ED₅₀ database.