Laser tattoo removal is an exciting procedure for both patients and practitioners alike, but few people understand the science behind the procedure. This section of our website is an introduction to the physics of laser tattoo removal and explains why laser tattoo removal is the most effective option for unwanted ink.
The Basic Laser Tattoo Removal Process
During a laser tattoo removal procedure, the practitioner guides a laser over the area of the tattoo. Unlike a laser pointer that produces a continuous beam of light, tattoo removal lasers produce pulses of light energy.
Each pulse of energy penetrates the skin and is absorbed by the tattoo ink. As the tattoo ink particles absorb the energy, they heat up and then shatter into tiny fragments. Then, over the weeks following treatment, the body’s immune system flushes the tattoo ink particles away from the location, lightening the appearance of the tattoo. Each laser treatment breaks down more and more of the tattoo ink until none remains.
What is Q-Switching?
Q-switching is a special type of laser pulse creation. Q-switched lasers produce intensely powerful, brief pulses of energy – typically lasting just a few nanoseconds.
Q-switched lasers are particularly useful for laser tattoo removal. Tattoo ink particles are extremely small (typically nanometers in diameter), and so they need to be heated for a very brief period of time to warm up and explode.
In contrast, skin cells are much larger and would need to be heated for a longer period of time to be damaged. Since a Q-switched laser pulse is so brief, it is capable of heating and shattering tattoo ink without heating the surrounding skin tissue. In essence, the briefness of the Q-switched laser pulse allows practitioners to selectively damage the tattoo ink particles while leaving the surrounding skin intact.
Targeting the Tattoo Ink
Tattoos come in every color imaginable. And, just like all other objects around us, different colors of tattoos absorb and reflect different wavelengths of light at different rates. For example, a red tattoo looks red because it absorbs green light and reflects the red light (which is what we see).
Because the goal of laser tattoo removal is to have the tattoo ink absorb the laser light, you want to make sure that the wavelength you use is well-absorbed by the tattoo. Returning to the example of the red tattoo, the red ink should be treated with green laser light, as it absorbs the green light (which makes the ink particles heat up and shatter). Since the 532 nm wavelength of laser light visibly looks green, it is the ideal wavelength to use for treating a red tattoo.
When treating multicolored tattoos, it is important to have access to a variety of laser wavelengths for treatment versatility. The most common wavelengths used for laser tattoo removal are 1064 nm and 532 nm – they can treat 95%+ of tattoos. Additional wavelengths that some practitioners use are 755 nm and 694 nm – these wavelengths function very similarly and are useful for treating rare ink colors, such as bright blue or green.
Letting the Body Do Its Work
Tattoo removal is not an instant fix – it’s usually a several month commitment for patients. Most tattoos require between 5 and 10 treatments to achieve complete removal, and the treatments must be spaced at least 6 weeks apart. Patients often ask why tattoo removal requires so many treatments and why they have to wait between treatments. As a practitioner, it’s important to know the answers to these questions to provide an informative patient consultation.
Laser tattoo removal requires multiple treatments because not all of the tattoo ink can be shattered in one treatment session. When a tattoo is applied, the ink is injected at different depths within the dermis. As the laser light is applied to the skin, the shallowest layers of ink in the dermis absorb the energy and shatter, but the deeper layers may not have been affected. Only once the body flushes away the top layers of ink can the deeper layers be treated. In effect, every successive tattoo removal treatment affects deeper and deeper layers of ink until none remain.
Patients need to wait between treatments because it takes time for the body to flush away the shattered tattoo ink from the location of the tattoo. The process of flushing away the ink involves immune system phagocytic cells gradually moving the ink particles to the lymph nodes, where the pigments remain. Because the body can only flush away the ink at a certain speed, it’s beneficial to wait as long as possible between treatments to see maximum fading from each session. Also, the waiting period allows any scabs or blisters to heal, minimizing the possibility of over-treating the area and causing unwanted side effects.
A Quick Discussion of the Alternatives
Laser tattoo removal is the only effective, non-invasive solution to unwanted ink. In decades past, people with unwanted tattoos had very few options – they could either undergo expensive excision surgery (which leaves a noticeable scar), use a damaging CO2 laser (which also leaves a large scar), or they would simply have to live with the tattoo.
Nowadays, there are a variety of tattoo removal creams or injections on the market, but these should all be avoided. The creams are simply ineffective – they have simply repackaged bleaching creams that cannot penetrate to the dermis, which is where tattoo ink is located. Injection methods are also highly suspect and often cause significant scarring.
Tattoos are popular, rates of tattoo regret are high, and laser tattoo removal is the only true solution to unwanted tattoos.