LASER EQUIPMENT FOR REJUVENATION

The first laser (LASER is an abbreviation of EnglishLight Amplification by Stimulated Emission of Radiation: light amplification using induced (stimulated) radiation)for cosmetic purposes (in ruby) was designed and testedvery recently, just 55 years ago, in 1960. Since then, laser cosmetology has been one of the most demanded areas in aesthetic medicine.

Laser devices are used with great success for hair removal, rejuvenation, lifting, removal of blood vessels, age spots, scars, stretch marks, post-acne, neoplasms, tattoos, for the treatment of vitiligo, psoriasis, acne(acne), ingrown toenails.

Today's review on laser equipment is highly specialized: we will familiarize readers in detail with devices for skin resurfacing.

LASER DEVICE

The laser consists of three main elements:

• power source (or "pump" mechanism);
• body of work (active environment);
• mirror system (optical resonator).

The energy sourcecan be an electrical discharge, a flash lamp, an arc lamp, another laser, a chemical reaction, etc. , which activate the working environment with their energy.

The working fluidis ​​the main determining factor of the wavelength generated, as well as other properties of the laser (monochrome, coherence, narrow focus). There are hundreds or even thousands of different working bodies from which a laser can be built. However, the following working media are most often used: liquid (consists of an organic solvent, for example, methanol, ethanol or ethylene glycol, in which chemical dyes are dissolved), gases (a mixture of gases, for example: carbon dioxide, argon, krypton, or mixtures such as neon heliollasers; these lasers are typically pumped by electrical discharges), solids (such as crystals and glass; solid material is typically activated by the addition of small amounts of chromium, neodymium, erbium, ortitanium); semiconductors.

Then, according to the type of working medium (active medium), the lasers are divided into:

• gas;
• liquid (on inorganic or organic dyes);
• metal vapor lasers;
• solid (crystals, glass);
• semiconductor (or diode).

Optical resonator, whose simplest form is two parallel mirrors, is located around the working medium of the laser. The forced radiation from the working medium is reflected between the mirrors and returns to the working medium, accumulating energy. The wave can be reflected many times before exiting. In more complex lasers, four or more mirrors are used, which also form an optical resonator, but of a more complex design.

The manufacturing and installation quality of these mirrors is one of the most important conditions for the quality of a laser system.

Additional devices can also be mounted on the laser system for various effects, such as rotating mirrors, modulators, filters, and absorbers. Its use allows changing the parameters of the laser radiation, for example, wavelength, pulse duration, etc.

TECHNICAL PARAMETERS OF THE LASER EQUIPMENT

Laser energy parameters:

1. Power, measured in watts (W).
2. Energy, measured in joules (J).
3. Energy density (J / cm2).
4. Pulse duration, measured in milli, nano, picoseconds.
5. Wavelength, measured in micrometers (μm) and nanometers (nm).

Laser radiation, which acts on a living organism, is subject to the phenomena of reflection, absorption and scattering. The degree of these processes depends on the condition of the skin: moisture, pigmentation, blood circulation, swelling of the skin and underlying tissues.

Many lasers target specific chromophores, which are biological structures that have a well-defined absorption spectrum. The ability of a chromophore to absorb light of different wavelengths with different intensities is determined by the absorption spectrum. The unit of measure for a chromophore's ability to absorb laser light is the absorption coefficient.

The absorption spectra of different chromophores differ dramatically. Therefore, it is important that the wavelength of the laser radiation matches the wavelength at the peak of the absorptive capacity of the chromophore that is planned to be exposed.

Therefore, there is no universal wavelength, that is, a laser, for all indications (appointments). So a laser for hair removal cannot rejuvenate the skin and vice versa. Of course, it happens quite often that various purposes are indicated in the laser instructions, but in fact there will be only one problem that such equipment effectively solves.

The penetration depth of laser radiation is inversely proportional to the absorption coefficient and, consequently, depends on the wavelength. For different skin chromophores (water, melanin, hemoglobin, oxyhemoglobin), the depth of penetration is also different. For example, in the visible region (0. 38-0. 74 microns, or 380-740 nm), the penetration depth will be 3-7 mm, in the infrared region (0. 76-1. 5 microns) -from 0. 5 to 1. 5 mm, and in the ultraviolet region (0. 3-0. 5 microns), the laser radiation is strongly absorbed by the epidermis and, therefore, penetrates the tissues at a shallow depth, from 0, 2 to 0. 4 mm.

LASER RADIATION GENERATION METHOD

There arepulsed and cw lasersthat generate radiation. Depending on the pumping method, a continuous and pulsed generation of laser radiation can be obtained. Pulsed light is generated as beams of waves that are interrupted for a specific period of time. Other lasers generate continuous light and a special device divides this light into short segments. As a general rule, continuous generation radiation lasers, in addition to physical therapy lasers, have the property of releasing unwanted heat at the site of exposure, which can lead to changes in the scars and damage to the tissues around the site. of exposition.

LASER POWER LEVEL

The radiation power of medical lasers (particularly cosmetic) varies within wide limits, determined by the purpose of their application. For continuously pumped lasers, the power can range from 0. 01 to 100 W. Pulsed lasers are characterized by power and pulse duration. The power of pulsed lasers is several orders of magnitude greater. Thus, a neodymium laser generates a pulse with an energy of E = 75 J, whose duration is t = 3x10-12 s. Pulse power: P = E / t = 2. 5x1013 W (for comparison: the power of the hydroelectric power station is about 109 W).

In cosmetology practice, even for skin rejuvenation procedures, laser radiation is used with both a low power value (low intensity laser radiation, LILI) and a high power value (high intensity laser radiation, VILI).

LOW INTENSITY LASER RADIATION (LLLT)

The action of LLLT is to activate enzymes in cell membranes and stabilize lipids. LLLT is known to stimulate cell division and development. The effect occurs at a subtle, atomic-molecular level, where energy is absorbed under the influence of laser radiation of a certain frequency (as a rule, in the red and infrared ranges). Such energy absorption leads to a sharp increase in the intracellular concentration of Ca2 +, that is, there is an activation of the accumulation and release of ATP, the restoration of cell membranes, an increase in intracellular metabolism and an increase in regenerative processes. due to the activation of cell proliferation (division). Old cells are intensively replaced by new ones and the biorhythm of this process is restored. The therapy uses low intensity lasers (with an intensity of 0. 1-10 W / cm2). The maximum wavelength for therapeutic lasers is 1300 nm. In particular, diode lasers are used for skin rejuvenation procedures:

• emitters with wavelengths of 890 nm and 915 nm (laser resurfacing);
• low intensity laser with a wavelength of 785 to 890 nm (laser biorevitalization and laser mesotherapy: delivery of active ingredients to the skin through LLLT).

Due to their low intensity, treatment with therapeutic lasers is painless and comfortable for the patient. In some cases, you may feel a slight heat. However, there is no rehabilitation period to obtain a pronounced effect (improvement of elasticity and firmness of the skin, micro-relief, hydration and tightening of the skin), a course of procedures and supportive procedures is required.

The basic set of therapeutic lasers includes a combined device with a control panel (sometimes in the form of a touch screen) and a handpiece emitter. The kit can include multiple emitters (for example, with a large area to work on the body and with a small area to work on the face), as well as accessories for various procedures. Therapeutic lasers have small dimensions, low power consumption, and the ability to install the working medium directly onto the handpiece, without using a light guide tool to deliver radiation.

HIGH INTENSITY LASER RADIATION (WHILE)

High intensity laser radiation (2500 J / cm2) allows considerable energy to be concentrated in a small volume, causing local thermal heating, rapid evaporation and hydrodynamic explosion in a biological environment. In cosmetology, VILI has the widest application, one of which is skin rejuvenation.

High intensity laser radiation skin resurfacing is a modern method to lift, remove and / or reduce the depth of wrinkles and improve skin quality. For high-intensity laser resurfacing, such devices are used, the radiation of which is well absorbed by water (since the skin is 77 percent water). The purpose of using such lasers is a rapid temperature rise in the absorption region of a laser pulse with flash evaporation of the tissue.

Among the variety of high intensity laser equipment for skin rejuvenation, specialists usually distinguish two main types of devices: for thenon-ablativeand theablative method.

Ablation: evaporation of superficial tissues by laser exposure.

Laser ablation devicesare extremely effective in fighting age-related changes in the skin: the breakdown of collagen and elastin, structural proteins of the skin that give it firmness and elasticity. Traumatic laser treatments are used to trigger renewal processes. In addition, it should be noted that the stronger the injury, the more powerful the rejuvenating effect, but at the same time, of course, the longer the rehabilitation period and the greater the risk of side effects.

That is why the main trends in the development of modern lasers for skin rejuvenation are the search for a compromise, an attempt to find a way to minimize trauma to the skin, but at the same time obtain apowerful response to a regenerative response.

Modern ablative devices include:

• fractional CO2 lasers (carbon dioxide lasers);
• Fractional erbium YAG lasers (solid state yttrium-aluminum-garnet crystal laser with erbium ions).

The term "factional" needs to be clarified immediately.

A fractional laser differs from a conventional laser in that the laser beam is forcibly divided into an array of microbeams ("fractions"). This can be implemented in hardware in several ways:

1. with the help of microlenses installed on the handpiece (a large number of rays simultaneously hit the skin);
2. in scanner mode, when a laser beam sequentially pierces the skin;
3. with a roller attachment, which is controlled by laser pulses and allows the procedure to be performed on the move.

This leads to the fact that the effect of the laser in a particular area of ​​the skin becomes not total, but zonal: not the entire skin surface is exposed to the effect, but thousands of its micro-areas, among which it remainsunaffected tissue. Fractional lasers are less traumatic: at the time of tissue processing, they do not cover the entire surface of the skin, but 3 to 70 percent, depending on the laser setting, while activating the recovery mechanism in the entire area.

In fact, thanks to the advent of fractional lasers, a new era of laser cosmetology began: laser procedures have become less painful, safer ("delicate"), the rehabilitation period after proceduresit has been significantly reduced (from two days to a week). At the same time, the clinical effectiveness did not decrease, but, on the contrary, increased.

Modern carbon dioxide laserswork according to the principle offractional photothermolysis, which consists in the formation of micro-coagulation zones in the form of columns perpendicular to the surface ofthe skin. The term "photothermolysis" here means the destruction of tissue under the influence of temperature, which arose in the process of transferring laser energy to the tissue (photo - light, heat - heat, lysis - destruction). The carbon dioxide laser has a radiation wavelength of 10. 6 microns. When performing the fractional rejuvenation procedure, this laser removes microzones of the skin practically in the entire depth of the epidermis (up to 20 microns), while the zone of thermal damage extends into the dermis by 150 microns or more, causing coagulationof collagen. This leads to the desired effect (reduction of denatured collagen fibers, smoothing of the skin).

Currently, there are several fractionated carbon dioxide devices on the market with adjustable flux density and pulse duration. This allows you to select the temperature and depth of the dermis heating. Thanks to new technologies, the time for a full post-procedure recovery has been reduced to one week. Companies - distributors of modern carbon dioxide lasers began to advertise the procedures performed with their help as "weekend" rejuvenation procedures, since during fractional laser photothermolysis, the "acute" rehabilitation period (intense edema and erythema) is done on two days off and on Monday the patient can go to work.

The erbium laser has a wavelength of 2. 94 microns and a much higher absorption coefficient than a carbon dioxide laser. Erbium laser radiation penetrates to a depth of approximately 1 micron, causing rapid vaporization of a thin layer of the epidermis with virtually no damage to surrounding tissues.

“The erbium (Er: YAG) laser is a typical ablative laser. The ablation effect is so pronounced that the upper layer of the epidermis instantly evaporates without leaving a trace. This laser is very suitable for rejuvenating, smoothing scars and removing pigmentation. "

Today, erbium lasers are actively used when working with the most sensitive areas: neck and décolleté, paraorbital and periorbital areas. With this laser, each point can be processed multiple times, while the doctor has the ability to control the entire "grinding" process. It is erbium lasers that plastic surgeons actively use during surgery. Also, erbium lasers are preferred when the patient is not ready for long-term rehabilitation.

Non-ablative high intensity lasersdo not work on the evaporation principle, but on the principle of heating the water and coagulation with the formation of new collagen in the affected areas.

To implement the non-ablative method, as a general rule, a laser with a great depth of penetration into the tissue is chosen. In this category, for rejuvenation, theneodymium laser (Nd: YAG)(neodymium doped yttrium-aluminum-garnet crystal) is mainly used, which has a wavelength of 1064 nm, which corresponds to the near infrared spectrum.

Radiation from such a laser can penetrate the dermis to a depth of 5 mm. In order to rejuvenate the skin, this laser is usually used in the pulse range of milliseconds and nanoseconds, which makes it possible to stimulate collagen synthesis (in almost all cases) without damaging the surrounding tissues, that is, in a nonablative. But by focusing on a small spot, it can also be used for ablation.

In modern cosmetology, neodymium laser is mainly used for removing unwanted vessels, such as spider veins, but also for photorejuvenation. The technique even has a separate name:non-ablative dermal remodeling. In this case, the object of influence is hemoglobin. The purpose of the action is to stimulate the growth of collagen. Heat is generated where laser radiation is most absorbed, such as the upper papillary layer, and spreads to nearby tissues. The consequence is a predictable inflammatory response that causes changes in dermal collagen synthesis with a concomitant skin renewal effect. Thus, due to the partial coagulation of the microvascular bed and the partial denaturation of the collagen structure, the laser triggers the formation of young fibroblasts.

I would especially like to highlight the latest advances in the field of laser technologies for skin rejuvenation: the appearance of picosecond lasers.

“In 2015, the focus of major international conferences on laser medicine was the use of picosecond lasers for rejuvenation. This is a completely new and promising technology that appeared only in 2014 and received FDA approval. The principle of operation of picosecond lasers goes beyond the theory of selective photothermolysis, since they affect the tissue not by heating (thermolysis), but by instantaneous supersaturation of the target with energy ”.

The picosecond laser generates pulses, the duration of which is measured in trillionths of a second. These short pulses do not have time to inflict thermal damage to tissues, but so much energy is concentrated in them that their target instantly disintegrates into microparticles, forming vacuoles. This exposure principle is called photomechanical exposure. In response to the formation of vacuoles in the dermal layer, a reaction begins that triggers the synthesis of new collagen.

The world's leading experts in laser medicine, providing independent reports on fractional picosecond technology, claim that these lasers provide an effect comparable to traditional ablative fractional lasers, absolutely painless for the patient. But the most important argument in favor of this technology for a modern metropolitan resident is the ultra-short rehabilitation, which takes from three to twenty-four hours. It should also be noted that it is not necessary to spend time on anesthesia before the procedure, and the process itself, due to the high repetition rate of the pulse, does not take more than thirty minutes. "

Lasers for skin rejuvenation can be divided into profile lasers and complex multifunctional laser systems ("combined").Each type of team has its pros and cons, fans and opponents. Many cosmetologists see more benefits in the so-called laser harvester.

“The modular platform allows the beautician's capabilities to gradually expand by purchasing other accessories. Each mouthpiece has its own type of emitter, and buying a mouthpiece is always cheaper than buying a separate device. It should be remembered that these modular systems allow the doctor to have all kinds of lasers to solve specific problems, and not use a laser for both hair removal and rejuvenation, because the selective principle implies that each wavelength will do one thing. well, and all other indications are secondary. Therefore, modular devices with accessories were made so that the clinic did not buy 5-6 separate devices, but had a modular platform with different laser accessories, and this is always more economical in terms of money and more rational in terms of load. than six separate lasers, each of which takes up space and is filled with patients at best two to three days a week. "

Some people think that the multifunctional device is not suitable for large clinics where doctors work "in the flow".

"Multifunctional machines have a major drawback: a failure of such a combine will mean the failure of all functions at once, and a combine is not always a good choice for a situation where there are several specialiststhe cabin "in operation" in different offices ".

In any case, the choice depends on the buyer and depends on many factors: the size of the company, the profile, the number and specialization of the doctors, the financing, in the end.

“The debate on the advantages and disadvantages of both versions is like arguing about the advantages of a smartphone with a camera over a DSLR. If you want to take photos, call and surf the Internet at the same time, the choice is obvious. But if you are a professional photographer, the capabilities of the phone's camera will hardly be enough for you. "

In order to correctly choose the laser resurfacing machine, experts recommend focusing on the following very important aspects:

1. It is necessary to request the results of the clinical trials of this model from the distributors.
2. You must speak with specialists from different salons and clinics that work in the team of interest, know their comments.
3. As a general rule, serious companies provide customers with the opportunity to test the device by salon specialists, so that employees and management can evaluate the effectiveness and advantages of the equipment offered.
4. All laser devices must have a registration certificate from the Ministry of Health and a declaration of conformity to the State Standard.
5. Attention must be paid to the fact that the term of use of the handles in some models is limited, this implies additional costs. Therefore, you should ask the vendor to provide a document confirming the guaranteed number of pulses and not be guided by the words of the manager selling the device.
6. Be sure to check with your dealer what consumables the device has (other than handpieces), how often they will need to be purchased, how much they cost, and if they are always in stock.
7. Find out how the device's post-warranty maintenance will be carried out, under what conditions, and within what time frame.
8. Find out who and how trains specialists to work on this device, how many specialists can be trained at the time of purchase, under what conditions, if the training will be repeated, if the specialist staff in your salon changes and under what conditions.

In conclusion, we would like to remind you that the use of laser techniques for rejuvenation requires that beauty salons and clinics have a medical license and specialists who have the right to provide services using equipment of this class: doctors who have received trainingunder the "Standard Program for Additional Professional Education of Physicians in Laser Medicine".