Titanium, a major constituent of blue ink, causes resistance to Nd-YAG (1064 nm) laser: results of animal experiments.

A blue tattoo is more resistant to laser therapy than black or brown tattoos. This study aimed to confirm titanium as a key response-disturbing constituent in a blue tattoo ink after Nd-YAG (1064 nm) laser treatment by animal experiments. Rabbits' backs were tattooed with four ink colours, and the Nd-YAG (1064 nm) laser was used to remove the tattoos. The response to the laser treatment in the rabbits was evaluated and electron microscopic studies were also performed. Excellent to fair responses were observed for the black, brown and dark brown inks, but the blue ink responded poorly to the laser. Histological examination indicated that the blue pigments were unchanged even after the laser treatment. Quantitative energy dispersive spectrometry revealed that blue ink contained high amounts of titanium. Our animal experiments confirm that a blue tattoo ink containing titanium, is a key element in poor response to the Nd-YAG laser.