Optimal tattoo removal in a single laser session based on the method of repeated exposures

Background: Unwanted tattoos are treated with Q-switched lasers. Despite a series of treatments, efficacy is limited. Objective: We compared a single Q-switched laser treatment pass with 4 treatment passes separated by 20 minutes. Methods: Eighteen tattoos on 12 adults were divided in half and randomized. One half received a single treatment pass (the "conventional" method) with a Q-switched alexandrite laser (5.5 J/cm(2), 755 nm, 100-nanosecond pulse duration, 3-mm spot size), and the other half received 4 treatment passes with an interval of 20 minutes between passes (the "R20" method). Tattoo lightening was compared 3 months later, by blinded evaluation of photographs. Biopsy specimens obtained before and immediately after treatment on both halves were also compared in blinded fashion. Results: Immediate whitening reaction occurred on the first treatment pass, with little or no whitening on subsequent passes. Three months later, treatment with the R20 method was much more effective than conventional single-pass laser treatment (P <.01; all tattoos favored the R20 method). Despite greater epidermal injury with the R20 method, neither method caused adverse events or scarring. Light microscopy showed greater dispersion of tattoo ink with the R20 method. Limitations: This prospective study involved a small number of subjects. Conclusions: The R20 method is much more effective than conventional laser tattoo treatment, removing most tattoos in a single treatment session. New laser device technology is not required to practice this method. (J Am Acad Dermatol 2012;66:271-7.)