Q-switches and picosecond lasers are standard equipment for medical beauty institutions. They are widely used, effective, and can be used to remove tattoos. When these two instruments appear at the same time, how should we choose? How should the parameters be set? How should the treatment endpoint reaction be judged?

Q-switched laser, also known as Q-switched laser, uses Q-switching technology, which is an effective way to obtain high-energy short pulses. Q-switched laser uses high-energy short-pulse laser to target pigment clumps in the skin through selective photothermal effect. After the energy of the laser is absorbed by the pigment particles, it causes them to expand and rupture rapidly, turning into tiny pigment particles, which are engulfed and metabolized by the body's macrophages.

Picosecond laser has a pulse width of picoseconds (10^-12 seconds), which can release extremely high energy in a very short time. This high-energy pulse will produce photoacoustic effect (or photomechanical effect), which will crush the tattoo dye particles or melanin particles into smaller particles. Due to the extremely short pulse width, the energy of the picosecond laser is more concentrated and the effect on the target tissue is more precise. This makes it easier for the pigment particles to be cleared by macrophages, while reducing thermal damage to the surrounding normal tissues. Therefore, picosecond laser is more effective than Q-switched laser in the treatment of tattoos and most pigmented diseases, and has fewer adverse reactions.

According to the "Expert Consensus on the Clinical Application of Picosecond Lasers", the evidence level of picosecond lasers in the field of tattoo treatment has reached level 1a, which is the highest level among all its indications and has become the gold standard for tattoo treatment. Picosecond lasers have shown a wide range of applicability and have excellent removal effects on tattoos of almost all colors. Numerous research observations have shown that compared with Q-switched nanosecond lasers, picosecond lasers have significant advantages in the treatment of laser tattoos, not only with fewer treatments and lower energy density, but also with a lower incidence of adverse reactions. The "Guidelines for the Diagnosis and Treatment of Common Diseases Related to Laser Cosmetology (2024 Edition)" also clearly stated that picosecond lasers are the first-line option for tattoo treatment. Although Q-switched lasers are also one of the important means of removing tattoos, the number of treatments is significantly more than that of picosecond lasers.

The pulse width of traditional Q-switched laser is at the nanosecond level (10^-9 seconds), while the pulse width of picosecond laser reaches the picosecond level (10^-12 seconds). In other words, picosecond laser can release greater energy in a shorter period of time, act more accurately, break up pigment particles more, and the postoperative reaction may be lighter and the recovery may be faster. A study selected 106 people with tattoos and divided them into a control group and a study group, with 53 cases in each group. The control group used Q-switched Nd:YAG laser (Israel Foton 2 laser photon workstation), treatment parameters: wavelength 1064/532 nm, spot diameter 3-5 mm, energy density 0.4-2.5 J/cm², frequency 2-5 Hz. The research group used picosecond laser (American Syneron PicoWay picosecond laser), treatment parameters: 1064 nm wavelength, energy density 4-6.5 J/cm²2, frequency 5-10 Hz. Both groups took the appearance of grayish white on the tattoo site as the treatment endpoint, and both were treated 1-5 times, with an interval of about 20 days each time.

The final data showed that picosecond laser treatment of tattoos had better clinical effects and less pain.

Figure. "A Randomized Controlled Study of Picosecond Laser Treatment for Tattoos"

The treatment parameters of picosecond laser mainly include spot diameter, pulse frequency and energy density. Different devices will have different parameter settings, so when choosing, you need to adjust according to factors such as the color, location, type of tattoo, and the patient's age and skin type. The following are some recommended parameter settings:

Nd:YAG 1064nm picosecond laser: The energy density of 1064nm wavelength is 1.0~1.6 J/cm², the spot diameter is 3~4mm, the pulse width is 290~500ps, and the treatment interval is 6~8 weeks.

During treatment, the handle should be kept vertical and the spot overlap should not exceed 10%. The treatment endpoint is usually based on the skin at the tattoo site turning grayish white immediately. If obvious epidermal damage occurs, the laser treatment energy should be reduced.

References:

1. Expert consensus on the clinical application of picosecond laser

2. Guidelines for the diagnosis and treatment of common diseases related to laser beauty (2024 edition)

3. Randomized controlled study of picosecond laser treatment for tattoos

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Foremed Legend

The core founding team of Suzhou Foremed Legend Medical Technology Co., Ltd. comes from Peking University and other well-known universities at home and abroad. Foremed Legend focuses on the design, research and development and application of high-end medical beauty optoelectronic equipment based on compliance and product strength, and is committed to becoming a leading company in the field of high-end medical beauty optoelectronic equipment in the world, a provider of integrated intelligent solutions for diagnosis and treatment, and a pioneer of medical beauty data integration platform.

Through tackling a series of underlying key technologies, Foremed Legend has now independently developed a number of high-end medical equipment such as picosecond laser therapy devices, long pulse laser therapy devices, intense pulsed light therapy devices, photoacoustic imaging skin detection devices and cold air therapy devices, and continues to deepen the research and development of core product technologies, using better technical solutions to benefit the vast number of beauty seekers.

Adhering to the principle of using technology for good, Foremed Legend will work with industry and ecological partners to bring more safe and effective medical aesthetic optoelectronic equipment and integrated diagnosis and treatment solutions to the global medical aesthetic market.