Simultaneous analysis of thermal and mechanical events during CW laser ablation of biological media

The purpose of this research was to gain better insight into the processes involved in ablation of biological media by continuous wave (CW) laser irradiation. In all experiments, a high-speed video camera and infrared camera were used simultaneously to observe and correlate the mechanical and thermal events associated with CW argon laser irradiation of various substances (porcine aortae, collagen fibers, and polyacrylamide control samples). Lateral temperature histories of rod specimens after ablation onset demonstrate the fact that the highest temperature achieved in each medium is located some distance along its axis rather than at the ablation front itself. Surface temperature recordings of tissue slabs describe the explosive nature of CW laser ablation of soft biological media, and threshold surface temperatures for argon CW laser ablation of various media were established. Fast video imaging reveals the dehydration, bubble formation, explosive events, subsequent boiling of remaining liquid, and eventual burning of the media corresponding to the thermal events recorded.