Benefits of the Use of Q-Switched Lasers for Tattoo Removal

It is well established that the Q-switched lasers are the gold standard in lasers to remove tattoos. Four wavelenghts are now available with Q-switching: frequency-doubled Nd:YAG at 532 nm (5-10 ns), ruby at 694 nm (25-40 ns), alexandrite: at 755 11m (50-100 ns), and Nd:YAG at 1,064 nm (5-10 ns). Comparative studies of the four Q-switched lasers have been reported. Though ruby, alexandrite, and Nd:YAG at 1,064 nm are all effective in dark tattoos, the ruby and the alexandrite have been reported to be somewhat more efficient than Nd:YAG. It is generally thought that Nd:YAG at 1,064 nm may be preferable in darker skin types due to its lower absorption by melanin and its greater tissue penetration. However, a study of Q-switched ruby and Nd:YAG lasers used in treating carbon based tattoos in Fitzpatrick V-VI patients showed mild transient hyperpigmentation with both lasers and mild texture changes with the Q-switched Nd:YAG laser. The alexandrite is most effective in treating blue and green tattoos and the frequency-doubled Nd:YAG may be effective in red tattoos, though the removal of red tattoos in general is challenging due to lack of appropriately selective wavelengths that are not absorbed by endogenous chromophores.

Before (a) and after (b) 5 laser treatments with QS-YAG 1,064 nm.

	Tattoo colors	Pulse duration (ns)	Wavelength (nm)	Q-switched lasers
	Red	510	532	Nd:YAG
	Black, blue, green	25-40	694	ruby
	Black, blue, green	50-100	755	alexandrite
	Black, blue	510	1064	frequency-doubled Nd:YAG

Blue-black carbon-based amateur tattoos respond best, requiring on the order of 5 sessions of Q-switched ruby, alexandrite, or Nd:YAG at 1,064 nm. In contrast, professional tattoos containing greater pigment density could require 10-15 sessions. Traumatic tattoos, such as gravel particles can also be treated, though their response is less predictable due to the heterogeneous nature of the impacted particles. Caution must be taken with traumatic tattoos induced by gunpowder or fireworks, as the laser impact can cause microexplusions and provoke pox-like scars.