Figure 1

The figure illustrates the experimental setup and the parameters used for the finite element model. In A the laser beams spatial profile is seen in the infrared camera. The slight skewed look of the profile is most likely due to fact that the cameras line of sight was not perpendicular to the skin surface. But it could also be due to the poor spatial resolution of the infrared camera and an inaccuracy of the laser optics. However, a Gaussian fit of the laser beam showed that the laser beam fits a Gaussian profile with an r² of 0.984. In B the experimental setup is displayed. It consists of a 100 W CO₂ laser with a beam expander and scanner head. The latter directs the laser beam to the desired skin sites. In C the principle behind the finite element model is displayed including thermal constants, geometric sizes and simulation properties. The lower boundary is kept at a constant temperature (0°C). Note that the initial temperature in the model is 0°C. This mimics how the thermal energy deeper into the tissue which is the primary cooling effect during laser stimulation.