Principle of laser treatment of pigmented lesions Laser treatment of pigmented lesions is based on the principle of selective photothermolysis, i.e. laser energy is absorbed by pigment particles (melanin vesicles, tattoo dyes) in the lesion in a very short time (10ns), generating a very high temperature (300°C), causing rapid expansion, forming micro-bursts, producing vaporization, crushing into very small particles, which are then phagocytosed, cleared by macrophages in the tissue and metabolized through the skin.