Laser tattoo removal often requires many repeated visits to remove even a small tattoo, and may result in permanent scarring. A brand of ink, InfinitInk, was developed to enable easier tattoo removal with a single laser treatment. The newer Q-switched lasers are said by the National Institute of Health to result in scarring only rarely, however, and are usually used only after a topical anesthetic has been applied. Areas with thin skin will be more likely to scar than thicker-skinned areas. There are several types of Q-switched lasers, and each is effective at removing a different range of the color spectrum. Lasers developed after 2006 provide multiple wavelengths and can successfully treat a much broader range of tattoo pigments than previous Q-switched lasers.
Experimental observations of the effects of short-pulsed lasers on tattoos were first reported in the late 1960s.[4] In 1979 an argon laser was used for tattoo removal in 28 patients, with limited success. In 1978 a carbon dioxide was also used, but generally caused scarring after treatments[5] It was not until the late 1980s that Q-switched lasers became commercially practical. One of the first published articles describing laser tattoo removal was authored by the group at Massachusetts General Hospital in 1990.[6]
Though not widely known by potential patients, the efficacy and safety of laser tattoo removal is well accepted in the dermatology community. Many reviews of laser tattoo removal methods, safety, and efficacy have been published in the dermatology literature.[7][8][9][10][11][12][13]
Tattoos consist of thousands of particles of tattoo pigment suspended in the skin.[14] While normal human growth and healing processes will remove small foreign particles from the skin, tattoo pigment particles are permanent because they are too big to be removed. Laser treatment causes tattoo pigment particles to heat up and fragment into smaller pieces. These smaller pieces are then removed by normal body processes.
Laser tattoo removal is a successful application of the theory of selective photothermolysis (SPTL).[15] For laser tattoo removal, SPTL for the selective destruction of tattoo pigments depends on four factors:
Q-switched lasers are the only commercially available devices that can meet these requirements.[16]
Several colors of laser light (measured as wavelengths of laser energy) are used for tattoo removal, from visible light to near-infrared radiation. Different lasers are better for different tattoo colors. Consequently, multi-color tattoo removal almost always requires the use of two or more laser wavelengths. Tattoo removal lasers are usually identified by the lasing medium used to create the wavelength (measured in nanometers (nm)):