Specific Laser Wavelengths Facilitate Tattoo Removal

A new study demonstrates that correlating distinct colors with appropriate laser wavelengths can selectively eliminate tattoo ink pigments.

Researchers at the Instituto de Química-Física "Rocasolano" (IQFR; Madrid, Spain) and the Instituto de Ciencia y Tecnología de Polímeros (Madrid, Spain) analyzed the absorption of tattoo inks related to their in vivo and in vitro behavior under laser irradiation, in an attempt to improve laser-assisted tattoo removal. The tattoo inks were first removed in vitro using pulsed laser radiation with different variables, and morphologic analysis of the irradiated areas was performed in a wavelength range from 300 to 800 nm, as characterized by reflection spectroscopy from samples consisting of inks mixed in gelatin. They then examined the absorption of 21 tattoo inks in a volunteer who was tattooed with two types of the inks tested in vitro, and then removed with lasers.

The results showed that reflection spectroscopy facilitated selection of the most adequate laser wavelengths for tattoo removal. Red, orange, and rose inks were successfully lightened at 532 nm with 0.6 J/cm²; brown at 1,064 nm with 0.3 J/cm²; yellow and green at 448 nm with 2.6 J/cm²; and blue at 600 nm with 0.9 J/cm². Similar colors in in-vitro and in vivo tattoos responded with the same efficiency to the laser variables. In addition, the tattoo removal process required shorter therapy sessions and spacing between sessions of 1-2 weeks, compared with the 4-8 weeks needed in other laser treatments. The study was published in the January 2010 issue of the Archives of Dermatology.

"High efficiency is reached in the removal of in vivo tattoos by using an irradiation wavelength at which the percentage of reflection from the pigment is minimal,” concluded lead author Clara Gómez, Ph.D., and colleagues. "Under this condition, laser pulses can be used with a low fluence, minimizing adverse effects and clinical time.”

Laser systems used for tattoo removal have provided fixed wavelengths. This often means different laser systems to treat multi-colored tattoos: pulsed-dye laser (510 nm) for removing yellow tattoos; YAG laser (1064 nm and 532 nm, fundamental and second harmonic wavelengths) for removing black and red tattoos, respectively; ruby laser (694 nm) for removing blue, black, and green tattoos; and alexandrite laser (755 nm) for removing blue and black tattoos. The fragmentation of the tattoo particles by the laser leads to small pigment particles, unknown decomposition products, and newly generated chemical compounds that may then be removed from the skin by means of the lymphatic system, leading to a noticeable lightening of a colored tattoo.

Related Links:
Instituto de Química-Física "Rocasolano"
Instituto de Ciencia y Tecnología de Polímeros