The Use of Lasers for Decorative Tattoo Removal

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 ).

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]

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.

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/cm.^[2] 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.

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]

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]

Skin Therapy Letter. 2006;11(5):8-11. © 2006 SkinCareGuide.com

Cite this: The Use of Lasers for Decorative Tattoo Removal - Medscape - Jun 01, 2006.