Tattoo Removal

Tattoo removal is most commonly performed using lasers that break down the ink particles in the tattoo into smaller particles. Dermal macrophages are part of the immune system, tasked with collecting and digesting cellular debris. In the case of tattoo pigments, macrophages collect ink pigments but have difficulty breaking them down. Instead, they store the ink pigments. If a macrophage is damaged, it releases its captive ink, which is taken up by other macrophages. Laser tattoo removal is considered to be the gold standard of tattoo removal treatment modality nowadays.
Laser tattoo removal is a successful application of the theory of selective photothermolysis. However, unlike treatments for blood vessels or hair the mechanism required to shatter tattoo particles uses the photomechanical effect. In this situation, the energy is absorbed by the ink particles in a very short time, typically nanoseconds. The surface temperature of the ink particles can rise to thousands of degrees but this energy profile rapidly collapses into a shock wave. This shock wave then propagates throughout the local tissue (the dermis) causing brittle structures to fragment. Hence tissues are largely unaffected since they simply vibrate as the shock wave passes. For laser tattoo removal the selective destruction of tattoo pigments depends on four factors:
The color of the light must penetrate sufficiently deep into the skin to reach the tattoo pigment. Pigments deeper in the skin are harder to remove than those near the surface.
The color of the laser light must be more highly absorbed by the tattoo pigment than the surrounding skin. Different tattoo pigments, therefore, require different laser colors. For example, red light is highly absorbed by green tattoo pigments, while yellow tends not to absorb light.
The time duration (pulse duration) of the laser energy must be very short so that the tattoo pigment is heated to fragmentation temperature before its heat can dissipate to the surrounding skin. Otherwise, heating of the surrounding tissue can cause burns or scars. For laser tattoo removal, this duration should be on the order of nanoseconds.
Sufficient energy must be delivered during each laser pulse to heat the pigment to fragmentation. If the energy is too low, the pigment will not fragment and no removal will take place.
Factors contributing to the success of laser tattoo removal:
There are a number of factors that determine how many treatments will be needed and the level of success one might experience. Age of tattoo, ink density, color, and even where the tattoo is located on the body, and whether the tattoo was professional, or not, all play an important role in how many treatments will be needed for complete removal. However, a rarely recognized factor of tattoo removal is the role of the client’s immune response. The normal process of tattoo removal is fragmentation followed by phagocytosis which is then drained away via the lymphatics. Consequently, it is the inflammation resulting from the actual laser treatment and the natural stimulation of the hosts’ immune response that ultimately results in the removal of tattoo ink; thus variations in results are enormous.