Fundamental and 2nd HarmonicNd: YAG Laser Shattering of Tattoo Dye Molecules
Susan Ibrahim Hassan
Abstract

Non-ablative laser removal of tattoo pigment is presented in this thesis. Q-switched Nd: YAG infrared laser and its second harmonic visible wavelengths were employed to shatter pigment clusters, deliberately injectedas tattoo spots - inside rabbit skin. These two wavelengths were selected in accordance with selective photothermolysis rule, where shattering of specific pigment is achieved, only when the laser wavelength matches the absorption spectrum of the pigment. The most important issue of this work is to vanish the pigment without causing any damage to the skin. The experimental work was carried out on domestic rabbits under licensing agreement and permission of animal care and use committee, Faculty of Veterinary Medicine, University Putra Malaysia. Quantitative and qualitative spectroscopic analyses of tattoo ink were calculated using black, brown, green, and red pigments as well as spectroscopic analysis achieved on rabbit skin. Tattoo laser treatment efficacy estimation was investigated by visible reflectance measurements and by histological analysis. Damage threshold of laser fluence was calculated for the two laser wavelengths to set up a fluence limit for safe tattoo removal. Responses to laser light were related to ink colors with greatest improvement noted with high fluence (16-20 J/cm2). Following a treatment with five laser sessions using 1064 nm wavelength, excellent tattoo clearance (≥95%) was seen for black ink and excellent (85–94%) for brown tattoos. With the use of 532 nm wavelength and after five sessions of treatment, a very good (75– 84%) result was achieved for red tattoo bars. Histological examination has demonstrated tattoo ink granules shattering effect without scarring..