The first laser (LASER is an abbreviation for the Englishlight amplification through stimulated radiation emission: light amplification with induced (stimulated) radiation)for cosmetic purposes (in ruby) was recently developed and tested before only55 years ago, 1960. Since then, laser cosmetics has been one of the most sought-after areas in aesthetic medicine.
Laser devices are used with great success for epilation, rejuvenation, lifting, removal of blood vessels, age spots, scars, stretch marks, post-acne, neoplasms, tattoos, for the treatment of vitiligo, psoriasis, acne (acne) and ingrown nails.
Today's review of laser devices is highly specialized: we will familiarize readers in detail with devices for skin rejuvenation.
LASER DEVICE
The laser consists of three main elements:
- energy source (or "pump" mechanism);
- working body (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. that activate the working medium with its energy.
Working fluidis the main determining factor for the generated wavelength as well as for other laser properties (monochrome, coherence, narrow focus). There are hundreds or even thousands of different working bodies on the basis of which a laser can be built. However, the following working media are most frequently used: liquid (consists of an organic solvent, for example methanol, ethanol or ethylene glycol, in which chemical dyes are dissolved), gases (a gas mixture, for example: carbon dioxide, argon, krypton or mixtures such as helium-neon laser (these lasers are mostly pumped by electrical discharges), solids (like crystals and glass; solid material is usually activated by adding small amounts of chromium, neodymium, erbium or titanium ions); semiconductors.
Depending on the type of working medium (active medium), lasers are divided into the following areas:
- gas;
- liquid (on inorganic or organic dyes);
- metal vapor laser;
- solid (crystals, glass);
- semiconductor (or diode).
Optical resonator, the simplest form of which is two parallel mirrors, is located around the working body of the laser. The forced radiation of the working medium is reflected between the mirrors and back into the working medium and collects energy. The wave can be reflected many times before it comes out. In more complex lasers, four or more mirrors are used, which also form an optical resonator, but have a more complex design.
The quality of the manufacture and installation of these mirrors is one of the most important conditions for the quality of a laser system.
Additional devices can also be installed in the laser system in order to achieve various effects, e. g. B. rotating mirrors, modulators, filters and absorbers. Their use allows changing the parameters of the laser radiation, for example, wavelength, pulse duration, etc.
TECHNICAL PARAMETERS OF THE LASER EQUIPMENT
Laser energy parameters:
- Power, measured in watts (W).
- Energy, measured in joules (J).
- Energy density (J / cm2).
- Pulse duration, measured in milliseconds, nano- and picoseconds.
- Wavelength, measured in micrometers (μm) and nanometers (nm).
Laser radiation that 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 certain 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 its absorption spectrum. The unit of measure for a chromophore's ability to absorb laser light is its absorption coefficient.
The absorption spectra of different chromophores differ radically. It is therefore important that the wavelength of the laser radiation coincides with the wavelength at the peak of the absorption capacity of the chromophore whose exposure is planned.
Therefore there is no universal wavelength for all indications (appointments), ie no laser. So a laser for hair removal cannot rejuvenate the skin and vice versa. Of course, quite often it happens that the laser instructions state multiple purposes, but in fact there is only one problem that such devices effectively solve.
The penetration depth of the laser radiation is inversely proportional to the absorption coefficient and consequently depends on the wavelength. With different chromophores of the skin (water, melanin, hemoglobin, oxyhemoglobin) the depth of penetration is also different. For example, in the visible range (0. 38 to 0. 74 micrometers or 380 to 740 nm), the penetration depth is 3 to 7 mm in the infrared range (0. 76 to 1. 5 micrometers) - from 0. 5 to 15 mm, and in the ultraviolet range(0. 3 to 0. 5 micrometers), laser radiation is strongly absorbed by the epidermis and therefore penetrates tissue to a shallow depth of 0. 2 to 0. 4 mm.
METHOD FOR GENERATING LASER RADIATION
There arepulsed and cw lasersthat generate radiation. Depending on the pumping method, continuous and pulsed generation of laser radiation can be obtained. Pulsed light is created as a wave beam that is interrupted for a certain period of time. Other lasers produce continuous light, and a special device divides this light into short segments. As a rule, lasers with continuously generated radiation, in addition to physiotherapy lasers, have the property of undesirable heat release at the exposure site, which can lead to scar changes and damage to the tissues surrounding the exposure site.
LASER POWER LEVEL
The radiation power of medical (especially cosmetic) lasers varies within wide limits, which are determined by the purpose of their application. For lasers with continuous pumping, the power can vary between 0. 01 and 100 W. Pulsed lasers are characterized by their pulse power and pulse duration. The power of pulsed lasers is several orders of magnitude higher. Thus a neodymium laser generates a pulse with an energy of E = 75 J, the duration of which is t = 3 × 10 −12 s. Pulse power: P = E / t = 2. 5 x 1013 W (for comparison: the power of the hydropower plant is approx. 109 W).
In the cosmetic practice, also for skin rejuvenation procedures, laser radiation is used both with a low power value (laser radiation low intensity, LLLT) and with a high value (laser radiation high intensity, LILI).
LOW INTENSITY LASER RADIATION (LLLT)
The effect of LLLT is to activate enzymes in cell membranes and stabilize lipids. It is known that LLLT stimulates cell division and development. The effect occurs on a subtle atomic molecular level, where energy is absorbed under the influence of laser radiation of a certain frequency (usually in the red and infrared range). Such energy absorption leads to a sharp increase in intracellular Ca2 + concentration, that is, activation of the accumulation and release of ATP, the restoration of cell membranes, an increase in intracellular metabolism and an increase in the processes of regeneration 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:
- emitters with wavelengths of 890 nm and 915 nm (laser taper);
- Low-intensity laser with a wavelength of 785 to 890 nm (laser biorevitalization and laser mesotherapy - delivery of active ingredients to the skin by LLLT).
Treatment with therapeutic lasers is painless and comfortable for the patient due to its low intensity. In some cases, you can feel a slight warmth. But there is no rehabilitation period, in order to achieve a pronounced effect (improving the elasticity and firmness of the skin, microrelief, moisturizing and lifting the skin), a number of procedures and supportive procedures are required.
The therapeutic laser principle includes a device combined with a control panel (sometimes in the form of a touchscreen display) and a handpiece emitter. The kit can contain several emitters (e. g. with a large work surface for working on the body and a small work surface for working on the face) and attachments for various procedures. Therapeutic lasers have small dimensions, low power consumption and the possibility of installing the working medium directly in the handpiece without using a light guide tool to emit radiation.
LASER RADIATION WITH HIGH INTENSITY (DURING)
Highly intensive laser radiation (2500 J / cm2) enables the concentration of considerable energy in a small volume, which in a biological environment leads to local thermal heating, rapid evaporation and hydrodynamic explosion. VILI is widely used in cosmetics, one of which is skin rejuvenation.
Skin rejuvenation with high-intensity laser radiation is a modern method of lifting, removing and / or reducing the depth of wrinkles and improving the quality of the skin. For high-intensity laser rejuvenation, devices are used whose radiation is well absorbed by the water (since the skin consists of 77 percent water). The purpose of using such lasers is a rapid rise in temperature in the area of absorption of a laser pulse with immediate tissue vaporization.
Among the various high-intensity laser devices for skin rejuvenation, specialists usually differentiate between two main types of devices: fornon-ablativeandablative method.
Ablation - evaporation of superficial tissue by means of laser action.
Laser ablation devicesare extremely effective in the fight against age-related changes in the skin: the breakdown of collagen and elastin - structural proteins in the skin that give it firmness and elasticity. Traumatic laser treatments are used to trigger the renewal processes. In addition, it should be noted that the stronger the injury, the stronger the rejuvenating effect, but at the same time, of course, the longer the rehabilitation period and the higher the risk of side effects.
Because of this, the main tendencies in developing modern lasers for skin rejuvenation are to find a compromise, to try to find a way to minimize trauma to the skin, but at the same time get a strong response to a regenerative response.
Modern ablative devices include:
- fractionated CO2 laser (carbon dioxide laser);
- fractionated erbium-YAG laser (solid-state yttrium-aluminum-garnet crystal laser with erbium ions).
The term "fraction" should be clarified immediately.
A fractional laser differs from a conventional laser in that the laser beam is forcibly split into a set of micro-beams ("fractures"). This can be implemented in hardware in several ways:
- with the help of microlenses installed in the handpiece (a large number of rays hit the skin at the same time);
- in scanner mode, when a laser beam successively perforates the skin;
- with a roller attachment that is controlled by laser pulses and enables the process to be carried out in motion.
This means that the laser effect on a certain skin area is not complete, but zonal: not the entire skin surface is exposed, but thousands of its micro-areas, between which the unaffected tissue remains. Fractional lasers are less traumatic: at the time of tissue processing, they do not cover the entire surface of the skin, but rather 3 to 70 percent, depending on the laser setting, while they trigger the recovery mechanism in the entire area.
Thanks to the advent of fractional lasers, a new era in laser cosmetology began: laser procedures have become less painful, safer ("sensitive"), and post-procedure rehabilitation time 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 on the principle offractional photothermolysis, which consists in the formation of microzones of coagulation in the form of columns perpendicular to the skin surface. The term "photothermolysis" here means the destruction of tissue under the influence of temperature that has arisen during the transfer of laser energy to tissue (photo light, thermal heating, lysis - destruction). The carbon dioxide laser has a radiation wavelength of 10. 6 micrometers. In fractional rejuvenation, this laser removes microzones of the skin from virtually the entire depth of the epidermis (up to 20 microns) while the zone of thermal damage extends 150 microns or more into the dermis, causing collagen coagulation. This leads to the desired effect (reduction of denatured collagen fibers, smoothing of the skin).
There are a number of fractionated carbon dioxide devices on the market today with adjustable flux density and pulse duration. This allows you to choose the temperature and the depth of heating of the dermis. Thanks to new technologies, the time for a full recovery after the procedure has been reduced to a week. Companies - distributors of modern carbon dioxide lasers began to advertise the procedures carried out with their help as a method of rejuvenation of the "weekend", since when performing fractional laser photothermolysis, the "acute" rehabilitation period (intense edema and erythema) in two days off and on MondayPatient passes can go to work.
The erbium laser has a wavelength of 2. 94 micrometers and a much higher absorption coefficient for water than a carbon dioxide laser. Erbium laser radiation penetrates to a depth of about 1 micron and causes rapid evaporation of a thin layer of the epidermis, with virtually no damage to the surrounding tissue.
“Erbium laser (Er: YAG) is a typical ablative laser. The ablation effect is so pronounced that the upper layer of the epidermis evaporates immediately and without leaving any traces. This laser is good for surfacing, smoothing scars, and removing pigments. "
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 several times, while the doctor can control the entire process of "grinding". These are erbium lasers that are actively used intraoperatively by plastic surgeons. Erbium lasers are also preferred when the patient is not ready for long-term rehabilitation.
Non-ablative high-intensity lasersdo not work on the principle of evaporation, but on the principle of heating water and coagulation with the formation of new collagen in the affected areas.
In order to implement the non-ablative method, a laser with a large penetration depth into the tissue is usually chosen. In this category, the neodymium-dopedneodymium (Nd: YAG) laser(neodymium-doped yttrium-aluminum-garnet crystal) is mainly used for rejuvenation, which has a wavelength of 1064 nm, which corresponds to thecorresponds to the near infrared spectrum.
The radiation from such a laser can penetrate the dermis to a depth of 5 mm. To rejuvenate the skin, this laser is usually used in the millisecond and nanosecond range of pulses, which (in almost all cases) can stimulate collagen synthesis without damaging the surrounding tissue, i. e. in a non-ablative mode. However, if you focus on a small area, it can also be used for ablation.
In modern cosmetics, the neodymium laser is mainly used to remove unwanted vessels such as spider veins, but also for photo rejuvenation. The technique even has its own name -non-ablative dermal remodeling. In this case, the object of influence is hemoglobin. The purpose of the action is to stimulate collagen growth. Heat is generated where the laser radiation is most strongly absorbed, for example in the upper papillary layer, and spreads to nearby tissues. The result is a predictable inflammatory reaction that causes changes in the dermal collagen synthesis with a simultaneous effect on skin renewal. 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 particularly like to mention the latest developments in the field of laser technologies for skin rejuvenation - the emergence of picosecond lasers.
“In 2015, the central topic of all major international conferences on laser medicine was the use of picosecond lasers for rejuvenation. This is an entirely new and promising technology that only hit the market in 2014 and has been approved by the FDA. The working principle of picosecond lasers goes beyond the theory of selective photothermolysis, as they do not affect the tissue by heating (thermolysis), but by immediately saturating the target with energy. "
The picosecond laser generates pulses, the duration of which is measured in trillionths of a second. Such short pulses don't have time to inflict thermal damage on the tissues, but there is so much energy concentrated in them that their target instantly breaks down into microparticles and forms vacuoles. This exposure principle is known as photomechanical exposure. In response to the formation of vacuoles in the skin layer, a reaction begins that triggers the synthesis of new collagen.
The world's leading experts in laser medicine, who provide independent reports on fractional picosecond technology, claim that these lasers provide an effect that is comparable to traditional ablative fractional lasers and is completely painless for the patient. However, the main argument in favor of this technology for a modern city dweller is the ultra-short rehabilitation, which lasts three to twenty-four hours. It should also be noted that there is no need to spend any time on anesthesia before the procedure and the process itself does not take more than 30 minutes due to the very high pulse repetition rate. "
Lasers for skin rejuvenation can be divided into profile lasers and complex multifunctional laser systems ("combines").Every type of equipment has its advantages and disadvantages, its fans and opponents. Many beauticians see more advantages in the so-called laser harvesting machine.
“The modular platform enables the beautician to gradually expand the skills of the beautician by purchasing other accessories. Each nozzle has its own type of emitter, and buying a nozzle is always cheaper than buying a separate device. It should be remembered that such modular systems allow the doctor to have all kinds of lasers to solve specific problems, and not to use one laser for both hair removal and rejuvenation, since the selective principle implies that each wavelength is one thingworks well, and all other indications are secondary. Therefore, modular devices with attachments were made so that the clinic would not buy 5-6 separate devices, but instead had a modular platform with different laser attachments. This is always cheaper in terms of money and more rational in terms of patient burden than six separate lasers, each taking up space and being loaded with patients two or three days a week at best. "
Some people think that the multifunctional device is not suitable for large clinics where doctors work “on the fly”.
"Multifunctional machines have an important disadvantage: A breakdown of such a combine harvester means a failure of all functions at once, and a combine harvester is not always a good choice for situations in which several specialists are" in operation "in the cabare in different offices. "
In any case, the choice rests with the buyer and depends on many factors: the size of the company, the profile, the number and specialization of doctors, the financing in the end.
“The debate about the advantages and disadvantages of both versions is like a dispute about the advantages of a smartphone with a camera over a DSLR. If you want to take photos, call and browse the web at the same time, the choice is obvious. But if you are a professional photographer, the capabilities of the phone camera will hardly be enough for you. "
In order to make the right choice for a laser rejuvenation machine, experts recommend focusing on the following very important aspects:
- The results of clinical studies of this model must be requested from the dealers.
- You should speak to specialists from various salons and clinics who are working on the devices of interest and find out their feedback.
- Reputable companies usually offer customers the opportunity to have the device tested by salon specialists so that staff and administration can evaluate the effectiveness and benefits of the proposed equipment.
- All laser devices must have a registration certificate from the Ministry of Health and a declaration of conformity to the state standard.
- Please note that the useful life of manipulators is limited in some models. This means additional costs. Therefore, you should ask the supplier to provide a document confirming the guaranteed number of pulses, and not be guided by the words of the manager who sells the device.
- Inquire with the dealer what consumables the device contains (in addition to tampering), how often they need to be bought, how much they cost and whether they are always in stock.
- Find out how maintenance of the device is carried out after the warranty, under what conditions and in what period of time.
- Find out who and how training specialists should work on this device, how many specialists can be trained upon purchase, under what conditions, whether the training will be repeated, whether the staff of specialists in your salon will change and under what conditions.
In conclusion, we would like to remind you that in order to use laser techniques for rejuvenation, beauty salons and clinics need a medical license and specialists who have the right to provide services with equipment of this class - doctors who have received special training under the"Standard program for the additional professional training of doctors in" have completed laser medicine ".