Laser tattoo removal.

Tattooing has been a part of human culture since the earliest beginnings of modern civilization. What has changed over the millennia are the myriad of colors with which we can now express our thoughts, feelings, and desires through body art. What has not changed is human nature, and our propensity to change our minds about what it is we think, feel, and wish to express on the canvas of our skin. Our fickle nature results in the desire to change what has been placed as a permanent reminder of a friend, spouse, or as a work of art. The technology used to remove tattoos began with destructive methods of removal, which wreaked havoc not only on the tattoo but more prominently on the skin containing that tattoo. The discovery of selective photothermolysis, the ability to selectively remove target structures without disrupting the surrounding skin, made it at least possible to remove tattoos without destroying the surrounding skin and leaving a scar. Theory predicted that pulse durations in the nanosecond domain would be optimal for tattoo removal, and the Q-switched neodymium:yttrium-aluminum-garnet, alexandrite, and ruby lasers operate in this range and are the key tools for modern tattoo removal. Too often, the wrong devices operating in the millisecond range, such as intense pulsed light sources, or lasers that are nonselective, such as the carbon dioxide laser, are used to treat tattoos, resulting in significant scarring without complete removal of the tattoo. Although the Q-switched lasers are capable of removing tattoos without harming the skin, removal often takes numerous treatments and still can be incomplete, especially when attempting to remove multicolored tattoos. Developments leading to removable tattoo inks, feedback systems to detect the absorbance characteristics of tattoo inks, dermal clearing agents, and perhaps even shorter pulse-duration lasers should result in improvements in tattoo removal in the near future.