What is the principle of Picosecond Laser Beauty

Picosecond laser beauty is a very common beauty technology nowadays. Because picosecond laser beauty is very common, it can treat acne scars, photoaging, and pigmented skin diseases of the skin and achieve very obvious results. However, although many people know the main effects of picosecond, they do not know what the principle of picosecond is. Only after understanding the principle can they clearly recognize the specific effects.

Picosecond laser is one of the latest laser technologies used in dermatology

It is mainly used for the treatment of dermatological pigmentary diseases, acne scars, photoaging, etc. Because of its significant therapeutic effect, few adverse reactions and short downtime, it has been widely used in clinical treatment abroad. Picosecond lasers currently mainly include 532nm, 755nm, and 1064nm lasers.

The application of picosecond laser in my country is still in its initial stage. For decades, Q-switched lasers with nanosecond (10?9s) pulse widths have been widely used in pigmented skin diseases, vascular skin diseases, skin rejuvenation, wrinkle removal, etc. However, their application still has some limitations, such as lack of obvious efficacy for some intractable pigmented diseases, possible risks of pigmentation and depigmentation, and damage to the normal skin around the lesions. To address these problems, picosecond (10?12s) laser was introduced into clinical practice. Compared with Q-switched laser, picosecond laser has higher energy density, is more targeted to color base, and causes less damage to surrounding skin. Since its introduction, picosecond laser has shown good clinical treatment effects and attracted widespread attention. This article reviews the clinical application and research progress of picosecond laser in skin beauty.

Overview

1. Treatment principle : Picosecond laser is a new energy source for treating skin diseases. It has an ultra-short pulse width of picoseconds (≤10ps). It was certified by the US FDA in 2012 and was used in the treatment of skin diseases. Different from the traditional selective photothermal effect, the main effect of picosecond laser is photomechanical effect rather than photothermal effect. When picosecond laser acts on target cells, it can generate a "mechanical wave" on the target base. The high energy generated instantly by this wave vaporizes the cells, and the pigment particles in the cells are completely shattered into dust. They can then be better taken up and metabolized by antigen-presenting cells, or the physical properties of some pigment particles can be changed to make them non-colorable. At the same time, due to its short pulse width, damage to surrounding tissues is reduced, and the risk of stimulating melanin regeneration is also significantly reduced.

2. Classification : The picosecond lasers currently used in clinical research mainly include Nd:YAG lasers with wavelengths of 1064nm and 532nm and pulse widths of 800ps, titanium:sapphire lasers with wavelengths of 785/500nm and pulse widths of 50ps, alexandrite lasers with wavelengths of 755nm and pulse widths of 100ps, infrared lasers (PIRL) with wavelengths of 2950nm and pulse widths of 55ps, and ND:YLF lasers with wavelengths of 1053nm and pulse widths of 40ps. However, the picosecond lasers currently used in clinical dermatological treatment are mainly alexandrite lasers with a wavelength of 755 nm and Nd:YAG lasers with a wavelength of 1 064/532 nm.

3. Advantages : The main working principle of Q-switched laser technology is selective photothermal effect, which mainly acts on melanin in the epidermis and dermis through thermal effect. Under the action of Q-switched laser, the fragments of melanin base are larger. After being phagocytosed by macrophages, the refractive index of pigment particles changes, so there is a certain period of pigmentation. Increasing the energy intensity or the number of treatments will increase the thermal load in the target tissue and improve the efficacy, but it will also increase the incidence of complications (such as hypopigmentation and small area texture changes), especially in patients with darker skin types III and IV. Compared with Q-switched laser, picosecond laser (10?12 s) has a shorter pulse width and higher peak power. Its biological effect on the skin is mainly photomechanical effect. The mechanical impact force generated by this photomechanical wave can completely disintegrate pigment particles with a wide diameter range. Even if the total pulse energy is much smaller than the nanosecond laser energy, most of the pigment particles in the entire irradiated area can be completely disintegrated. The finer pigment particles produced after picosecond laser irradiation are more easily phagocytosed by macrophages, so the pigment clearance rate is high. In addition, the action time of picosecond laser is 1 to 3 orders of magnitude shorter than that of Q-switched laser. The laser energy required to achieve the same therapeutic effect is less than that of Q-switched laser. Its thermal diffusion to surrounding tissues is less than that caused by Q-switched laser. Therefore, it causes less damage to surrounding normal tissues, and patients feel less pain during treatment. The corresponding adverse reactions are also significantly reduced, and the postoperative downtime is shorter.