To this end, we first characterized a variety of marketed tattoo inks by means of reflection measurements. Because modern tattoo needles place granules of ink in the mid dermis, which makes deep penetration of laser light into the skin necessary to achieve tattoo removal, we incorporated selected and well-characterized pigments into in vitro experimental models of skin made of gelatin and proceeded to irradiate the samples under controlled laser variables. Considering that the engulfment of the tattoo particles by macrophages or their incorporation into fibroblasts may change their optical properties, a volunteer was tattooed using 2 of the well-characterized inks, and the evolution of the in vivo tattoos and the skin reaction to laser irradiation was carefully controlled. In the present work, inks from different worldwide suppliers, including pigments of similar but not identical color, were first characterized and then used. This study’s conclusions might provide general guidance for optimizing lightening therapy.
The authors make it clear that this is an initial study which will require further exploration. This said, their study suggest:
The studies herein demonstrate that the selection of adequate laser variables guarantees the selective elimination of tattoo pigments in vivo, even using a density of energy significantly lower than those usually reported in the literature.We found that under the present conditions, fluences of 0.7 to 1.6 J/cm2 were effective in the removal of tattoos compared with fluences of 9.0 to 12.0 J/cm2 commonly reported in the literature.In addition, the tattoo removal process in the present case required shorter therapy sessions and spacing between sessions of 1 to 2 weeks compared with the 4 to 8 weeks needed in other laser treatments.
The authors also make a “plea” for improved laser technology which would involve use of only one laser, not multiple laser for patients with multi-colored tattoos:
An attractive alternative to the existing laser systems would be a solid-state dye laser. Such a laser could be built to be a compact, versatile, hazardless, and easy-to-handle system, allowing broad, rapid wavelength tuning over the entire visible spectral region. With this objective in mind, we have dedicated our recent systematic efforts to design and synthesize laser-efficient and photostable dye-doped optical materials to build an industrial prototype of a solid-state dye laser. As demonstrated herein, such a laser system will have immediate applications in tattoo removal processes. On the other hand, developments leading to new biodegradable tattoo inks, feedback systems to detect the absorbance characteristic of tattoo inks, dermal clearing agents, and perhaps even lasers with shorter pulse durations might also improve therapy results in the future.
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