ED50 Study of Femtosecond Terawatt Laser Pulses on Porcine Skin

摘要

We report on our measurements of the Minimum Visible Lesion (MVL) thresholds for porcine∗skin [Yucatan mini-pig (Sus scrofa domestica)] for laser exposures at 810 nm and sub-50femtosecond (fs) laser pulses. In this study we measured the ED50 skin thresholds from laserpulses that produced multiple self-focusing filaments while propagating from the laser to theskin. These high-powered (1-2 terawatt) filaments were focused on the flank of mini-pig andthree trained readers determined the number of lesions becoming visible at 1-hour and 24-hourpost-exposure. The observed damage patterns on the skin surface indicated the number offilaments in the laser pulse and these were photographed for future reference. Histologicalsections were obtained after both readings and the results will be reported later for sub-surfacedamage. The threshold using preliminary data at 1-hour was 9 mJ of energy and increased to 25mJ after 24 hours. This increase in threshold indicated that many of the laser pulses producedonly superficial damage (erthemia) that disappeared in 24 hours and that nearly 3 times the pulseenergy was required to cause subsurface or cellular damage.