Dr Klaus Hoffmann talks about picosecond laser treatment of European tattoos
In the early days of tattoo removal, lasers were used which more or less cooked the pigment with thermal action and often left scarring. These procedures mainly involved the use of Alexandrite laser 755 nm and Nd:YAG lasers 1064 and 532. They worked beautifully for black, and also for some dark colours, but not so well for the other colours.
In 2012 about ten treatments were needed to remove at least 58% of black tattoos and 15-20 treatments was the norm. The need for greater effectiveness and speed has pushed things forward and with the new technologies such as Q switched laser it’s now possible to give a reduced number of sessions and get better results with a wider range of colours—so patients may be paying higher prices per session for new technology, but they get more effective and faster results.
A Q-switched laser uses flash-lamps to pump energy in a special laser medium. By using two mirrors the energy is captured in a tube and is released in one big pulse with extremely high peak power. Q-switched lasers can used to remove tattoos by shattering tattoo pigment into particles that are cleared by the body’s lymphatic system. In 2013 the picosecond laser was introduced which showed better results with colours such as green and light blue which had until then been more difficult to remove.
Newer lasers using picosecond technology like Picosure claim better clearance with fewer treatments and less fluence without injuring the surrounding skin. This means the skin isn’t cooked and it’s less likely to cause scars and eodoma—since it penetrates less deep—so removal is easier.
The Picosure in burst modus can go down to 550 picoseconds. This powerful device also offers the option to change the hertz, the delivery rate, the size of the spot and also the joules per square cm. A zoom hand-piece allows the focus and energy to be changed. Meanwhile, there’s an additional hand-piece available which delivers 532nm, which is an additional laser pumped by the 755nm device—so essentially a picosecond laser, on a picosecond laser. The previous weaknesses of the 755nm in some of the red tattoos is covered now by this 532nm hand piece.
Technology continues to evolve, and by the end of 2016 a new system will be available that adds 670nm (Ruby) with full picosecond versatility also.
The tattoo artist does not have a single needle, he has different needles and can use several at the same time. He can work very deeply, or very superficially. Even after seeing hundreds of tattoos its still impossible to know exactly how much ink has been used, how deep it sits, or to know how each patient will react to the tattoo ink.
Single tattoo ink particles aggregate and then agglomerate together within the skin. There are different particle sizes in different depths and often in different inks. Black ink is standard carbon. The inorganic pigments that are also used for red, yellow and orange are a little more complicated. Within an ink there are binders, pigments, solvents and additives. Normally, only the inorganic pigments, this 32% that makes the colour, are spoken about. However, there are many other things surrounding these inorganic pigments such as titanium and silica. For example, in a red tattoo the red molecule is between the silica—used to make the colour a little bit lighter—so this must be removed as well as the colour.
The system for tattoo removal works on melanin. Melanin does the same as the colours in the depth and forms three-dimensional crystal structures. The situation is the same as for black ink—the structure can be diminished, by physical forces, by the photo acoustic effect. Once it has been hit and broken off, then the body is able to remove the structures.
Melanin absorbs 755nm beautifully and there is then an avalanche process within the melanin as the melanin molecules form aggregates like a crystal – this explains why the photoacoustic pressure wave can smash them. In addition, the plasma formed by the pulse has several biological effects due to increased biosignal from cytokines and several other pathways.
The pulse duration of Picosure is extremely short, extremely powerful and far superior to older systems. Compared to the Accolade, it’s 90 times better and the peak power is an extreme 360 MW—enough to eliminate for several picoseconds.
Using a long pulse laser and overheating the pigment in the depth, will cause damage and the patient has to face side effects. The effects of picolaser are the same as from dye lasers—the dye laser blows the vessel. With picosecond, structures are blown by photo acoustic effects, rather than mechanical effects, and a shorter pulse will hit smaller particles. At least three companies have come to the conclusion that 700 picoseconds is the time duration of choice. It makes no sense to go deeper, because at greater depth and with more power a so-called plasma threshold is reached. The plasma that is formed within the skin and over the skin blocks the in-depth penetration of the photons and makes it impossible to penetrate.
Photo acoustic effect
The photo acoustic effect involves heating up the surface of a structure, in an extremely short period of time, with extremely high energy. This causes the particles to expand, hit together and then break apart. Particle fragmentation is linearly dependent on the laser fluence and quadratically dependent on the pulse duration.
To remove very tiny particles requires a shorter pulse duration. The Picosure Boost can go down to 550 picoseconds, allowing removal of very tiny particles, under the size of 40 nm. In theory this can have impact on red and some effect with yellow.
Yellow is harder to move than other colours. When comparing 6% pigments in black and 26% pigments in yellow—there are lots of extremely tiny particles which are harder to remove than with other colours. Bigger particles are blown to dust and this dust is taken by macrophages in the lymph. When it comes to removing yellow, the Picosure now can solve the problem with the 532.
It takes several days for the aggregates in the depths to really form, so trying to remove a tattoo immediately after application will be very effective. Sometimes I’m asked to remove tattoos that people regret after a couple of days and am extremely successful.
Often when a tattoo is in the lumbar region a lot of ink, has penetrated very deep, in several layers of the skin, and very high energies are needed to get it out. It’s often best to work stage by stage here and we accept some blistering.
Removing a tattoo that has been covered up two or three times, means you have a lot of ink to face and it’s harder to remove.
Picosecond can hit black tattoos 3-5 times faster than it was possible in the past. Melanin is hit best by 755—it can be removed effectively and does not require treatment with laser or heat within the skin
The picosecond technology is a completely new world. It will be something the adds new possibilities not only for tattoo removal but for skin rejuvenation and treatment of different hyperpigmentations as well.
Dr Hoffmann is head of the German Laser Center ZELM-NRW supported by the local government with about 21 different lasers plus three IPL’s including both new picosecond lasers. He is organiser of the congress www.cosmedica.de, the largest German congress with live surgery, plenary sessions as well as workshops. He has experience in about 100 clinical trials since 1987. He is honorary president of the International Society for Bioengineering and Imaging of the skin. He has introduced high frequency ultrasound and several other noninvasive measuring techniques to dermatology.