Response of Pigmented Porcine Skin (Sus scrofa domestica) to Single 3.8 micron Laser Radiation Pulses

摘要

Background and purpose: The purpose of this study is to determine the impact of melanin on skin response to single 3.8 micron, eight microsecond laser pulses and the difference in lesion formation thresholds for input into laser safety standards. Williams et al., performed a study examining laser tissue interaction from 3.8-micron lasers in lightly pigmented Yorkshire pigs (Sus scrofa domestica). However, studies performed by Eggleston et al comparing pigmented and lightly pigmented skin with human skin found that the Yucatan mini-pig is a superior model for laser skin exposures. Methods: Five Yucatan mini-pigs under general anesthesia were exposed to 3.8 micron laser pulses ranging from 0.8 J/cm~2 to 93 J/cm~2. Gross examinations were done acutely and 24 hours after laser exposure. Skin biopsies were then collected at various times post exposure, and histologic examinations were conducted. Results: The 24 hour ED_(50) was determined to be 4.5 J/cm~2 with fiducial limits of 6.2 and 2.2 J/cm~2. As deposited energy was increased, the lesion presentation ranged from whitening of the epidermis (4 J/cm~2) to whitening with inflammatory centers (14 J/cm~2), and at the highest energy levels inflammatory areas were replaced with an epidermal ulcerated central area ( ≥ 21 J/cm~2). Conclusion: Preliminary findings suggest pigmentation or melanin may play a minor role in the mechanism of laser-tissue damage. The ED_(50) of Yorkshire pigs was 2.6 J/cm~2. The ED_(50) of the Yucatan mini-pig was found to be 3.6 J/cm~2, and although it was higher, it is still within the 95% fiducial limits.