The Use of Lasers for Decorative Tattoo Removal

K. Mariwalla, MD1; J. S. Dover, MD, FRCPC1 ^1-3

1. Department of Dermatology, Yale University School of Medicine, New Haven, USA
2. SkinCare Physicians, Chestnut Hill, USA
3 Department of Medicine (Dermatology), Dartmouth Medical School, Hanover, USA

ABSTRACT

As the incidence of tattoo placement continues to increase, so does the demand for tattoo removal, with more than 10 million people in the US alone with a tattoo. Used in an appropriate clinical setting, Q-switched lasers provide relatively efficacious clearance of decorative tattoo pigment with minimal side-effects. We present our clinical experience along with literature findings on decorative tattoo removal and the important issues practitioners should consider in the management of tattoos.

Key Words:
tattoo, laser

In the United States, an estimated 7–20 million people carry at least one tattoo.¹ Recently, Laumann and Farmer conducted a random survey of 500 men and women and found a prevalence of tattooing in 26% of males and 22% of females. Of those with tattoos, 17% considered tattoo removal.² The top reasons for tattoo removal are to improve self-esteem, to remove a disliked design, and to increase credibility with friends.³

Prior to laser technology, tattoos were removed via techniques with a high likelihood of scarring, such as surgical excision and cryosurgery. Unfortunately, no one laser system can remove all available tattoo inks. This review provides our clinical experience and recommendations for decorative tattoo removal.

The Tattoo

Essentially, tattoos are exogenously placed chromophores. Amateur tattoos are less dense, placed at variable depths, and composed of carbon-based ink. Professional tattoos contain a variety of densely packed, colored pigments at a uniform depth. Once implanted, the ink particles are phagocytosed by resident dermal fibroblasts, where they permanently remain in the superficial dermis.⁴

Laser Removal

In order to selectively remove tattoo pigments placed in the dermis, pulsed lasers must meet the following criteria:

a) The laser wavelength must be well absorbed by the targeted ink.
b) The heat generated should be spatially confined to the target.
c) The energy delivered must be sufficient to cause the desired effects.⁵

Quality-switched (Q-switched) lasers (lasers with ultrashort energy pulses in the nsec domain) with wavelengths in the visible-to-near infrared range (532–1064nm), enable the deposit of energy very quickly, producing a “photoacoustic” effect. The intense heat transients cause some particles to shatter and kill the cells in which the pigment resides. The rupture of pigment-containing cells eventually triggers phagocytosis and the packaging of tattoo fragments for lymphatic drainage.⁶

Several issues are important when evaluating a tattoo for removal (Table 1).⁷ Amateur tattoos generally require fewer treatment sessions than professional tattoos. Distally located tattoos are more difficult to remove, and older tattoos may or may not be easier to remove than newer ones.⁸ Lastly, bright-colored inks may necessitate more treatment sessions.

Q-switched Laser Systems

The use of Q-switching laser pulses was first explored with the Q-switched ruby laser (QSRL) (694nm), and expanded to include the Q-switched neodymium: yttrium-aluminum-garnet (Nd:YAG) laser (532nm and 1064nm) and the Q-switched alexandrite laser (755nm).

The absorption spectrum of tattoos is unknown, with some colors responding better than others. As a result, a combination of laser systems may be used in stages for a single tattoo (Table 2).

Q-switched Ruby Laser (694nm)

The QSRL is effective for the removal of black, blue, and green inks. The laser penetrates to a depth of approximately 1mm and has spot sizes up to 6.5mm. Because this wavelength is well absorbed by melanin, caution should be used, as injury to melanocytes can lead to transient hypopigmentation and even depigmentation as well as textural change. The goal of treatment should be immediate tissue whitening (corresponding to water vapor in the skin) with minimal or no bleeding, and as with all laser treatments, no more than 10%–20% spot overlap should be employed. When compared to the other Q-switched lasers, the QSRL was shown to have the highest clearing rate after four and six treatments of blue-black tattoos. However >95% clearance was only obtained in 38% of the tattoos.⁹ For amateur tattoos, it has been reported that a mean of 4.92 treatments are needed to achieve clearance of > 90% of pigment.¹⁰ Other studies suggest only 11%–28% of professional tattoos achieve >75% clearance after more than six treatments.^11,12

Q-switched Nd:YAG Lasers (532nm and 1064nm)

The Q-switched Nd:YAG laser system overcomes the obstacle of excessive melanin absorption and is used to remove blue and black ink and tattoos in darker skin types (1064nm), or red pigment (532nm). The clinical endpoint following laser treatment is whitening of the skin with occasional mild pinpoint bleeding. Current models offer a spot size range of 1.5–8mm, which may be more appropriate for eyeliner tattoos.

532nm

The 532nm wavelength (green light) is absorbed by hemoglobin, and as a result, purpura lasting 1 week to 10 days frequently occurs after treatment. This wavelength is also effective for red, orange, and occasionally yellow ink. In 63% of red tattoos, > 75% clearance was achieved after one to five treatments at 2.5 J/cm2. In this same study, only two of eight yellow tattoos faded.¹³

Some reports have detailed the paradoxical darkening of red tattoo pigment as well as other skin-toned, yellow, and pink tattoos.^14,15 This occurs as the laser pulse reduces ink from rust-colored ferric oxide (Fe2O3) to jet black ferrous oxide (FeO).¹⁶ Similarly, bright colors may contain white ink made up of titanium dioxide (TiO2, T4+) that is reduced to TiO2 or blue Ti3+ upon laser treatment.

1064nm

The long 1064nm wavelength has the deepest penetration and carries the least risk of hypopigmentation; however, it is also the least effective in removing brightly colored pigments. Of all the laser systems, it is the one we recommend for use in darker skin types. This wavelength may also be useful when residual, more deeply placed ink particles are all that remain, as well as in the treatment of eyeliner tattoos, because it is less likely to damage the hair follicle.

Ferguson and August found that 79% of amateur black tattoos were >75% clear after one to five treatments at 1064nm, and 74% of professional tattoos achieved similar clearance but required up to 11 treatments (average 6.3).¹³

Q-switched Alexandrite Laser (755nm)

Although this laser system has the least amount of tissue splatter owing to its slightly longer pulse duration of approximately 50nsec (compared to 5– 15nsec for the Nd:YAG and 15–40nsec for the ruby laser) it is not as successful as the other models. Similar to the QSRL, the alexandrite is most effective for removing black, blue, and green inks. As with the other lasers, the clinical endpoint is tissue whitening. In a study by Stafford, et al., an average of 11.6 treatments was required to completely remove professional blue-black tattoos, compared with 10.3 treatments for the same results in subjects with amateur tattoos. Hypopigmentation occurred in 80% of treated subjects, which resolved within 3–4 months of treatment.¹⁷

Further Research

As noted, the data available for solid colors have been mixed and may not be adequate for patient satisfaction. As a result, picosecond lasers such as the titanium:sapphire (795nm) laser are being compared to current Q-switched technology. It is theorized that by confining thermal and photomechanical damage to the target particle more effectively, these lasers may optimize tattoo removal either by increased phagocytosis or through transepidermal elimination. Initial animal studies¹⁸ have been promising, as was a study in human subjects that showed a higher success rate of tattoo clearing with fewer laser treatments.¹⁹ To date, however, only prototypes of this laser are available.

Conclusion

While no single laser system holds the answer for tattoo removal, Q-switched lasers can successfully fade most tattoos with minimal adverse effects. In understanding the capabilities and limits of current laser technology, practitioners can set realistic goals
with their patients. Complete clearance of all treated tattoos is rare. At best, depending on the color, practitioners can expect 75% clearance in half the cases they treat. As the demand for tattoo placement increases, research continues to perfect tattoo removal with the development of picosecond and femtosecond laser systems.

References

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