Therapeutic Update: Using Lasers for Tattoo Removal

February 2014 | Volume 13 | Issue 2 | Features | 108 | Copyright © February 2014

Deborah S. Sarnoff MD

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An estimated 10% of the US population has at least one tattoo, with up to one fourth in those younger than 30 years of age. Yet more than half of all people with tattoos eventually regret having them and many want them removed.1
Tattoos are made up of small particles of pigment located in the dermis. The discovery of selective photothermolysis has facilitated the targeted destruction of tattoo pigment with only minimal damage to surrounding skin.2
There are three conditions that must be met for successful tattoo removal. First, the ink molecules must absorb the beam to convert a sufficient amount of light energy to heat. Transient skin whitening serves as an indicator of proper light absorption by the tattoo pigments. Second, the radiant exposure of the applied laser pulses must be high enough to generate a sufficiently high temperature increase in the ink particle. Third, the pulse duration must be very short (in the range of nanoseconds or picoseconds) due to the small size of the ink particles.3

Q-Switched Lasers

A special technique, known as “Q-switching” provides high intensity, ultra short pulse durations. Use of a quality-switched (QS) laser for tattoo removal (694 nm ruby) was first reported in 1965 by Leon Goldman.4 But it was not until the theory of selective phototherymalysis was introduced in 1983 that QS lasers became the gold standard for modern day tattoo removal. 5 A Q-switched laser is necessary to achieve selective photothermalysis, as the exposure time in the nanosecond (10-9) domain is less than half the thermal relaxation time of the target pigment.
A QS laser ensures that the thermal damage is confined to the target chromophore, resulting in photoacoustic destruction and minimizing damage to the surrounding skin from thermal diffusion. The four QS laser wavelengths are in the visible and infared spectrum, and include the 694 nm ruby, the 755 nm alexandrite, the 1064 nm Nd:YAG and the 532 nm KTP. If a tattoo is comprised of different colors, several wavelengths must be used to target the tattoo pigments, which have different absorption characteristics (see chart).6 The lighter one’s skin the more successful the procedure will be because the melanin in darker skin competes with the laser’s beam of light, thus making the light less likely to reach the deeper level of pigment. The QS Nd: YAG is usually recommended when treating tattoos on Fitzpatrick type IV to VI patients, as the 1064 nm wavelength penetrates deeper and is minimally absorbed by epidermal melanin.
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Immediately upon treatment, there is a photoacoustic effect, which creates a very superficial wound. It is not unusual for some of the tattoo pigment to come off with dressing changes. But the main fading of the tattoo color occurs as a delayed phenomenon weeks after treatment. It is the result of cellular mechanisms ie, phagocytosis by macrophages, which transport and dispose of the ink particles via the lymphatic system. Laser treatments are usually spaced 1 to 2 months apart. However, it may take up to three months for the full effect of a single treatment to be realized. The difficulty with tattoo removal is that it can take up to 10 to 15 treatment sessions to remove the unwanted pigment. A recent retrospective review of 238 patients who underwent an average of 3.57 treatments (ranging between 1 to 18 sessions) found that only 1.26% achieved total clearance of the tattoo defined as complete absence of pigment.7 Many patients get discouraged and discontinue treatment due to the expense and/or prolonged treatment regimen. Even after a series of numerous treatments, in some cases, complete removal is still not possible.

The “R20” Protocol and “RO” Protocol

Laser tattoo removal is typically frustrating for patient and doctor alike since it can take numerous treatments at 1-2 month intervals. The limiting factor when treating a tattoo has been that