Laser assisted tattoo removal - state of the art and new developments.

Decorative tattoos including permanent make-up are very popular world-wide. However, some people regret tattooing and seek tattoo removal. Tattooed skin contains numerous solid particles of tattoo pigments. A major mechanism of tattoo removal is laser assisted fragmentation of these particles, which are then transported away from the skin. For many years, Q-switched lasers with nanosecond pulse durations at high light intensities have been applied to cause such fragmentation via rapid heating up while sparing the adjacent tissue. Despite the long-lasting use of such laser treatment, the exact mechanisms of laser assisted fragmentation are hardly investigated. Due to short and intense laser pulses applied, non-linear effects of light (e.g. photoacoustic and optical breakdown) and nonlinear thermal properties in tattoo particles may play a crucial role. In the past few years, lasers with even shorter pulse duration in the sub-nanosecond range were launched for tattoo removal. Theoretical considerations assumed that pulse durations shorter than nanoseconds allow even more effective fragmentation of tattoo particles. A couple of initial studies affirm the effectiveness of picosecond pulses in tattoo treatment, especially in clearing black tattoos. Furthermore, treatment with picosecond lasers seems to be less painful. Consequently, picosecond technology may be a new strategy for more effective removal of tattoo pigments at a lower rate of side effects. But there is an urgent need for more well-designed and randomized controlled trials to compare this treatment modality to the traditional nanosecond technology regarding efficacy and adverse reactions.