Picosecond lasers for tattoo removal: a systematic review

Abstract

Given that the pigment particles in tattoos have a relaxation time of <10 ns, picosecond lasers would be expected to be more effective than nanosecond lasers in tattoo removal. To systematically review the evidence regarding the effectiveness and safety of picosecond lasers for tattoo removal, Pubmed, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov, and reference lists were searched for relevant trials. The primary outcome was >70 % clearance of tattoo pigment. Secondary outcomes were 90-100 % clearance of tattoo pigment, number of laser sessions required, and adverse effects. Eight trials were included, six with human participants (160 participants) and 2 with animal models. Seven of the eight trials explored the usage of either 755, 758, 795, 1064, or 1064/532-nm picosecond lasers for black and blue ink tattoos. In the human trials, 69-100 % of tattoos showed over 70 % clearance of pigment after 1-10 laser treatments. Reported side effects included pain, hyperpigmentation and hypopigmentation, blister formation and transient erythema, edema, and pinpoint bleeding. Included articles varied in type of laser investigated, mostly non-comparative studies and with a medium to high risk of bias. There is sparse evidence that picosecond lasers are more effective than their nanosecond counterparts for mainly black and blue ink tattoo removal, with minor side effects.

Visualization of laser tattoo removal treatment effects in a mouse model by two-photon microscopy

“…The commonly used pulse lasers for tattoo removal are Qswitched lasers producing nanosecond (ns) pulse durations of approximately 5 -100 ns at various wavelengths such as ruby (694 nm), alexandrite (755 nm), and Nd:YAG (532 nm and 1064 nm) lasers. Picosecond (ps) pulse lasers, which have shorter pulse durations of 350 -750 ps, have been developed recently [1][2][3][4][5]. The logic is that ns pulse duration might be too long for effective photothermolysis of small tattoo particles having thermal relaxation time (TRT) in ps ranges.…”

Laser tattoo removal: do we already have picosecond lasers?

“…Dies ist der Ansatzpunkt, da aus technischer Sicht die derzeitigen Geräte nicht im Pikosekundenbereich, sondern im Sub-Nanosekundenbereich arbeiten. Inzwischen hält diese Erkenntnis immer mehr Einzug in Patientenforen [6], aber auch unter Laserdermatologen [7]. Das Ergebnis unserer randomisierten kontrollierten Studie, in der wir einfarbige schwarze Tattoos behandelten, zeigte dies zu unserer eigenen Überraschung deutlich [5].…”

Picosecond laser applications in aesthetic dermatology

“…Since most tattoo particles' size are approximately 100 nm, corresponding to a thermal relaxation time of less than 10 ns, picosecond (PS) lasers could be more effective than QS lasers, theoretically. Clinical trials have reported the efficacy and safety of PS lasers in the treatment of multicolored and recalcitrant tattoos [3] .…”

“…The ability of PS lasers to remove multicolored tattoos was shown for green, yellow, red, and purple tattoos. However, the findings was not directly compared with the results of the traditional QS lasers [3] .…”