The Q-Switch Breakthrough
The introduction of Q-switched (QS) lasers in the early 1990s was a major breakthrough in tattoo removal. QS lasers emit nanosecond energy pulses that can be used for selective photothermolysis. Different wavelengths are absorbed by different pigments. The energy converts to heat, which breaks down the pigment into particles that can be cleared by the macrophages. “We work with an array of QS lasers. There is too much risk of scarring with any other type of tattoo removal,” says Elliot T. Weiss, MD, Laser & Skin Surgery Center of New York in Manhattan and Southampton, New York. “Our workhorses are the Sinon Q-Switched Ruby laser (Palomar Medical, www.palomarmedical.com) and an Nd:YAG. Some doctors get by with just an Nd:YAG laser, but in my opinion they do not work as well on light skin.” Another reason for owning multiple lasers is that different ink colors respond better to different laser wavelengths.
“For example, green inks respond best to the QS ruby or QS alexandrite lasers,” explains David B. Vasily, MD, Aesthetica Cosmetic & Laser Center, Bethlehem, Pennsylvania. “Blue and brown inks respond nicely to the ruby as well, while red and orange do well with the 532nm QS Nd:YAG. Black inks respond to the ruby, YAG or alexandrite wavelengths. Yellow inks do not respond well to any laser wavelength. In my opinion, there is no one box or laser that contains all these wavelengths with adequate peak power to address all colors.”
“Because most tattoos are black, I
recommend an Nd:YAG as the first line treatment for tattoos,” says Eric F. Bernstein, MD, Main Line Center for Laser Surgery, Ardmore, Pennsylvania. Because the 1064nm wavelength is the longest QS wavelength available, it has the least ability to “see” melanin pigment, yet it is still absorbed “very strongly by black tattoo ink,” says Dr. Bernstein. “Thus, this laser is safest to use on skin of color and works extremely well on any skin type. I just got the new RevLite SI (ConBio, www.conbio.com), and it is simply awesome. This laser allows one to select the maximum fluence and continually vary spot sizes, so I can use the largest possible spot size with the desired fluence. This means that more of the laser energy reaches the tattoo in the dermis. I also use the new Alex TriVantage (Candela, www.candelalaser.com). This laser is capable of removing multicolored tattoos: the 755nm wavelength works extremely well for blue and green tattoo inks and it has the 532nm wavelength to treat red ink.”
While there have been no major changes in tattoo removal lasers since the advent of the Q-switched laser, device manufacturers are making incremental changes. “Newer Q-switched lasers offer shorter pulses and a general trend toward refining the beam profile and adding enough power to allow larger spot sizes,” says Dr. Weiss.
Image of results one year after receiving four treatments on the same day with a ruby laser. The ruby laser targets melanin more intensely than the Nd:YAG and can cause hypopigmentation. (Photo courtesy of Richard FItzpatrick, MD)