Thermographic and Histological Evaluation of Laser Skin Resurfacing Scans

In general, ablative laser skin resurfacing procedures have shown good short-term efficacy. However, the mechanisms underlying laser skin resurfacing remain poorly understood. We performed a quantitative study to investigate the thermal response of skin to CO2 laser irradiation. Raster scans were performed on an in vivo rat model and radiometric surface temperatures measured using a thermal camera. Temperatures approaching 400 C were measured during the scans and remained above the initial skin temperature for durations longer than ten seconds. Analysis of histology sections showed that the epidermis remained partially intact after three passes. To explain the observed trends in the temperature response and histology, the dynamics of optical and thermal parameters were investigated. Water vaporization played a key role in governing the response of the skin to subsequent laser passes. Char formation and pulse stacking altered the thermal effects.