Laser‐tattoo removal—a study of the mechanism and the optimal treatment strategy via computer simulations

Abstract

Computer simulations confirm that the breakup of tattoo particles is photoacoustic. For the same amount of laser energy, a shorter pulse is more efficient. The optimal pulse length is approximately 10-100 picosecond to minimize the laser fluence and the collateral damage. It is more difficult to break up the smallest tattoo particles that have diameters smaller than 10 nm; however, smaller particles are less important because they are less visible. Tissue surrounding the tattoo particles can be damaged by cavitation bubbles. These bubbles could be the cause of the empty vacuoles in the ash-white lesions throughout the dermis seen after treatment. Steam-carbon reactions can be induced. Particles then become grossly transparent because of this reaction. Different laser intensity should be used for pigments at different depths in order to minimize the collateral damage to the dermis.

Treatment of resistant tattoos using a new generation Q‐switched Nd:YAG laser: Influence of beam profile and spot size on clearance success

“…Theoretical calculations support the argument that picosecond laser pulses should be more effective at clearing tattoo particles than nanosecond pulses. Clinical studies are limited and it is unknown whether resistant tattoos can be treated effectively by high-fluence picosecond pulses [11][12][13]. Unfortunately, high-energy picosecond pulses are difficult and expensive to generate, so that very small spot sizes (<0.5 mm) would be required to produce high enough fluences.…”

Can topically applied optical clearing agents increase the epidermal damage threshold and enhance therapeutic efficacy?

“…We used the freeware Monte-Carlo multilayered (MCML) code [6] to perform first order calculations of the heat source term (J/cm 3 ) in tattooed skin, assuming a slab geometry. Optical properties were derived from data presented in various sources [1,7,8]. Epidermal and superficial papillary dermal (upper 200-300 mm thickness) scattering coefficients were varied from 0.4 mm À1 (assumed to be native skin at 694 nm) to decreased values of 0.2 and 0.1 mm À1 after the application of clearing agents.…”

The Q-Switched Nd: YAG Laser in Tattoo Removal and the Effect of Lymphatic Elimination: An Experimental Study in Rabbits

“…Pigments in laser therapy groups are found to be placed as small fragments around the vacuoles, partially phagocytosed by the macrophages. Literature review reveals that these vacuoles are formed due to the gas released after the thermal effect leading to inflammation reaction due to the photothermal affect [4]. These vacuoles are also hold responsible for the sudden paleness of the tissues right after the administration of the tattoo pigment.…”

“…However each method presents with its own advantages and disadvantages. "Selective photothermolysis" theory mentioned by Anderson and Parrish summarize that lasers only effect the pigment that are charged with wavelength specific chromophores [3][4][5].…”