Fig 1.
Clinical photographs of removal of red, green, and black pigments over time.
The 532 nm lasers were the most effective in removing red colored tattoos by week 3. The 532 nm picosecond laser resulted in less epidermal damage post-treatment and rapid healing than the 532-nm nanosecond laser. The 755 nm picosecond laser was the most effective in removing green colored tattoos. Note: Pre: pre-treatment; Post: immediately after laser treatment; Week 3: 3 weeks after the laser treatment.
Table 1.
The mean scores of tattoo removal rate on clinical photographic assessment.
Fig 2.
(a) Colorimetric intensity was measured and compared before and 3 weeks after the treatment. The 532 nm picosecond laser exhibited > 50% change in pigment intensity in all colors except black. (b) The 755 nm picosecond laser was only effective in removing green and blue colors, and the changes in green and blue pigment intensities were the greatest. (c) The 1064 nm nanosecond laser had almost no effect in removing any color except black. However, the 1064-nm picosecond laser resulted in > 50% decrease in yellow, green, and blue pigments, while also effectively reducing red and orange colors.
Fig 3.
Ultrastructural analysis of colored tattoos using electron microscopy (EM).
The EM results following treatment with picosecond lasers in all colors revealed a typical rimming pattern along the peripheries of the lysosomal lobules. Unlike the picosecond laser, the nanosecond laser treatment resulted in tattoo particles that left the lysosomal structure and were scattered in cellular spaces, thereby disrupting the cell structures (inlet: a magnified photo of the rimming pattern; black arrowhead: rimming pattern of tattoo particles) (bar = 2 μm).
Table 2.
Summary of histopathologic findings on tissue damage.
Table 3.
Efficacy of tattoo removal and the effects on surrounding tissues of nanosecond and picosecond lasers according to wavelength.