Investigation of skin damage by carbon dioxide laser and semi-automated evaluation of the degree of damage

This work deals with the extent of damage to the skin surface when electromagnetic radiation with a wavelength λ = 10.6 μm is applied. This investigation aims to determine a threshold value above which skin damage occurs. For this purpose, a semi-Automated evaluation routine was developed, tested and assessed. Skin damage was generated by applying a carbon dioxide laser in a line scan profile to pig skin which was selected to model human skin. Both, the laser power and the exposure time of the radiation were systematically varied. The samples were evaluated by VIS images on which a semi-Automated evaluation routine was performed. The damage classification was based on the visible change of the thermally damaged zone. To reduce influences of the test personnel, a region of interest was defined in the center of each damage. The length was kept constant to ensure comparability. Based on the calculated data, the relation of the induced surface energy and the damaged area could be displayed and analyzed. The progression follows a sigmoidal function, so that above a threshold value a sharp increase in damage can be observed in the exposed area.