Lasers in dermatocosmetology

At present, low-energy laser radiation has been widely used in medicine. By its nature, laser radiation, like light, refers to electromagnetic oscillations of the optical range.

Laser (Lazer - light amplification by stimulated emission of radiation is a technical device emitting in the form of a focused focused beam coherent monochromatic polarized electromagnetic radiation, ie light in a very narrow spectral range.

Properties of laser radiation

Coherence (from Latin cohaerens - connected, connected) is the consistent flow in time of several vibrational wave processes of one frequency and polarization, the ability to mutually reinforce or weaken one another during the addition, that is, coherence is the propagation of photons in one direction , having one frequency of oscillation (energy). Such radiation is called coherent.

Monochromaticity - radiation of one specific frequency or wavelength. Radiation with a spectral width of less than 5 nm is taken as monochromatic radiation.

Polarization is the symmetry (or symmetry breaking) in the distributions of the orientation of the vector of electric and magnetic field strength in an electromagnetic wave relative to the direction of its propagation.

Directivity is a consequence of the coherence of laser radiation, when photons have one direction of propagation. A parallel light beam is called collimated.

The biological effect of laser radiation depends on its physical parameters, radiation power, dose, beam diameter, exposure time, radiation regime.

Radiation power is the energy characteristic of electromagnetic radiation. Unit of measurement in SI - Watts (W).

Energy (dose) - the power of an electromagnetic wave emitted per unit time.

The dose is a measure of the energy acting on the body. Unit of Measurement in SI is Joule (J).

Power density is the ratio of the radiation power to the area of falseness perpendicular to the direction of radiation propagation. Unit of measurement in SI - Watt / meter ² (W / m ^g ).

The dose density is the radiation energy distributed over the surface area of the exposure. The unit of measurement in SI is Joule / meter ² (J / m ² ). Density of the dose is calculated by the formula:

D = Pcr x T / S,

Where D is the dose density of the laser action; Pc is the average radiation power; T is the time of exposure; S is the area of impact.

There are several modes of radiation: continuous - under this mode the power does not change during the exposure; modulated - it is possible to change the amplitude of the radiation (power); pulse - radiation occurs in a very short period of time in the form of rarely repeated pulses.

To facilitate the work of a specialist with laser equipment, there are various tables for calculating the average radiation power depending on the area of irradiated tissues, the diameter of the light spot, the distance to the object, the time of exposure, the radiation regimes, and the use of nozzles. It should be noted that in each specific case the specialist makes a decision on the parameters of the effect, taking into account the severity of the disease, the general condition of the patient, and the capabilities of the laser apparatus.

When calculating the dose, it is necessary to take into account that with a remote exposure technique, about 50% of the energy is reflected from the skin surface. The coefficient of skin reflection of electromagnetic waves of the optical range reaches 43-55%. For women, the reflection coefficient is 12-13% higher; In older persons, output power is lower than in young people. The coefficient of reflection in individuals with white skin is 42 + 2%; at not dark skin - 24 + 2%. When using the contact-mirror technique, almost all the input power is absorbed by the tissues in the affected area.

All lasers, regardless of their type, consist of the following basic elements: the working substance, the pump source and the optical resonator consisting of mirrors. Medical laser devices have a device for modulating the radiation power for continuous lasers or a generator for pulsed lasers, a timer, a radiation power meter, instruments for bringing radiation to irradiated tissues (light guides and nozzles).

Classification of lasers (according to BF Fedorov, 1988):

1. According to the physical state of the working substance of the laser:
   • gas (helium-neon, helium-cadmium, argon, carbon, etc.);
   • Excimer (argon-fluorine, krypton-fluorine, etc.)
   • Solid-state (ruby, alumite garnet, etc.);
   • liquid (organic dyes);
   • semiconductor (arsenide-gallium, arsenide-phosphide-gallium, selenide-lead, etc.).
2. By the method of excitation of the working substance:
   • optical pumping;
   • pumping due to gas discharge;
   • electronic excitation;
   • injection of charge carriers;
   • thermal;
   • chemical reaction;
   • others.
3. According to the wavelength of the laser radiation.

In the passport data of laser devices, the specific wavelength of the radiation, determined by the material of the working substance, is indicated. The same wavelengths can generate different types of lasers. At λ = 633 nm, lasers: helium-neon, liquid, semi-spontaneous (AIGalnP), on gold vapor.

4. By the nature of the radiated energy:
   • continuous;
   • impulse.
5. Average power:
   • high-power lasers (more than 10 ³ W);
   • low power (less than 10 ^-1 W).
6. By degree of danger:
   • Class 1. Laser products that are safe under the intended operating conditions.
   • Class 2. Laser products that generate visible radiation in the wavelength range from 400 to 700 nm. Eye protection is provided by natural reactions, including a flashing reflex.
   • Class FOR. Laser products that are safe for observation by an unprotected eye.
   • Class ЗВ. Direct observation of such laser products is always dangerous (the minimum distance for observation between the eye and the screen should be at least 13 cm, the maximum observation time is 10 s).
   • Class 4. Laser products that create dangerous scattered radiation. They can cause skin damage, fire hazard.

Therapeutic lasers belong to the class of ZA, ZV.

7. From the angular divergence of the ray.

The least divergence of the beam has gas lasers - about 30 arc seconds. In solid-state lasers, the divergence of the beam is about 30 angular minutes.

8. On the coefficient of efficiency (EFFICIENCY) of the laser.

The efficiency is determined by the ratio of the laser radiation power to the power consumed from the pump source.

Classification of lasers (for the purpose of exposure)

• Multipurpose:
  • lasers on carbon dioxide (CO2);
  • semiconductor laser.
• For the treatment of vascular formations:
  • yellow krypton laser;
  • yellow copper vapor laser;
  • Neodymium YAG laser;
  • argon laser;
  • pulsed with llam fire-flash laser on dyes;
  • semiconductor laser.
• For treatment of pigmented formations:
  • Pulsed laser with flash lamp on dyes;
  • a green copper vapor laser;
  • green krypton laser;
  • Neodymium - YAG laser with frequency doubling and Q-switching.
• To remove tattoos:
  • ruby laser with Q-switching;
  • alexandrite laser with Q-switching;
  • Neodymium-YAG laser with Q-switching.
• For the treatment of cutaneous neoplasms:
  • a laser on carbon dioxide;
  • Neodymium - YAG laser;
  • semiconductor laser.

Low-intensity laser radiation

The use of low-intensity laser radiation in dermatocosmetology in the form of an auxiliary method, in the complex treatment of skin diseases, after surgical manipulation on the face allows painless, atraumatic reduction of the duration of exacerbations of the skin process, and achieve a stable clinical remission.

Low-energy laser radiation has a multifactorial effect on the human body. Under the influence of laser radiation, changes take place that are realized at all levels of the organization of living matter.

At the subcellular level: the emergence of excited states of molecules, the formation of free radicals, an increase in the rate of protein synthesis, RNA, DNA, the acceleration of collagen synthesis, the change in the oxygen balance and the activity of the oxidation-reduction process.

At the cellular level: changing the charge of the electric field of the cell, changing the membrane potential of the cell, increasing the proliferative activity of the cell,

At the tissue level: a change in the pH of the intercellular fluid, morphofunctional activity, microcirculation.

At the organ level: the normalization of the function of an organ.

At the systemic and organismic level: the emergence of response complex adaptive neuro-reflex and neuro-humoral reactions with the activation of sympathetic-adrenal and immune systems.

The method of laser therapy (LT), used in clinical practice in recent years, has a universal multifactor action:

• analgesic and vasodilating;
• reduction of endogenous intoxication, antioxidant protection;
• activation of tissue trophism, normalization of nervous excitability;
• intensification of bioenergetic processes;
• biostimulating effect on microcirculation (due to increased hemocirculation and activation of neoplasm of collaterals, improvement of rheological properties of blood;
• anti-inflammatory effect, is also carried out by improving trophism, reducing hypoxia and swelling in the focus of inflammation, enhancing regeneration processes;
• increased phagocytic activity of leukocytes;
• bactericidal effect, has a bacteriostatic effect on staphylococcus, Pseudomonas aeruginosa, vulgar proteus, E. Coli;
• normalization of cellular and humoral immunity, due to increased production of immune bodies and phagocytic activity of leukocytes;
• general desensitizing action.

Against the backdrop of laser therapy, the energy function of the skin is restored, the proliferation of fibroblasts is activated in the epidermis and dermis, the cellular infiltrate is reduced in the dermis, and the intercellular edema disappears in the epidermis.

Different types of lasers cause different reactions of the biotissue. The above physical characteristics provide the basis for choosing the type of laser from the entire variety of laser systems available, in accordance with medical indications.

Indications for use of low-intensity laser radiation

The main indication is the expediency of application:

• the need for stimulation of blood and lymph circulation, regeneration processes;
• increased collagen production;
• activation of the process of biosynthesis.

Private indications:

• skin diseases - dermatitis, eczema, herpetic infection, pustular diseases, alopecia, psoriasis;
• cosmetic problems - aging, wilting, thinning of the skin, wrinkles, cellulite, etc.

Contraindications to the appointment of low-intensity laser therapy

Absolute:

• malignant neoplasms;
• hemorrhagic syndrome.

Relative:

• pulmonary-cardiac and cardiovascular insufficiency in the stage of decompensation;
• arterial hypotension;
• diseases of the hematopoiesis;
• active tuberculosis;
• acute infectious diseases and febrile conditions of unexplained etiology;
• thyrotoxicosis;
• diseases of the nervous system with a markedly increased excitability;
• diseases of the liver and kidneys with a pronounced deficiency of their functions;
• period of pregnancy;
• mental illness;
• individual intolerance to the factor.

In dermatocosmetology, laser therapy is used in the form of:

1. external irradiation of lesions:
   • direct non-contact exposure;
   • direct scanning effect;
   • contact local action with a rigid lightguide;
   • with the use of a contact-mirror nozzle, an applicator massager;
2. laser reflexotherapy - exposure to biologically active points (BAP);
3. irradiation of reflex-segmental zones;
4. transcutaneous blood irradiation in the area of the projection of large vessels (NLOK);
5. endovascular blood irradiation (BLOCK).

If it is necessary to influence the patient with different physical factors, it is necessary to remember that low-intensity laser therapy is compatible and well combined with the appointment of basic medical therapy; with water procedures; with massage and physiotherapy; with the action of a constant magnetic field; with ultrasound.

In a single day, the appointment of several types of physiotherapeutic procedures is incompatible if it is impossible to provide the required time interval between them, which is not less than eight hours; irradiation of the same area with ultraviolet radiation; it is unreasonable to perform laser therapy with the influence of alternating currents; and incompatible with laser therapy sessions with microwave therapy.

The effectiveness of laser therapy is enhanced by the use of the following antioxidants (according to VI Korepanov, 1996):

• Reopoliglyukin, gemodez, trental, heparin, no-shpa (to improve microcirculation).
• Solution of glucose with insulin (to make up for energy losses).
• Glutamic acid.
• Vitamin K, a regenerable lipid bio-oxidant.
• Vitamin C, a water-soluble antioxidant.
• Solcoseryl, which possesses antiradical activity, improves microcirculation.
• Vitamin E, lipid antioxidant.
• Vitamin PP, involved in the restoration of glutathione.
• Pipolphen.
• Kefzol.

Technique and procedure of procedures

Laser irradiation is carried out both by the defocused and focused beam; remotely or contact. Defocused laser radiation affects large areas of the body (on the area of the pathological focus, segmental or reflexogenic zones). Focused laser beam irradiate pain points, acupuncture points. If there is a gap between the radiator and the irradiated skin, the technique is called remote; if the radiator touches irradiated tissues - the technique is considered contact.

If the radiator does not change its position during the laser therapy session, the technique is called stable; When the radiator is moved, the technique is called labile.

Depending on the technical capabilities of the laser apparatus and the area of the irradiated surface, one of the following methods is used:

Method 1 - act directly on the site of the lesion. This technique is used to irradiate the lesion of a small area (when the diameter of the laser beam is equal to or greater than the pathological focus). Irradiation is carried out in a stable manner.

Method 2 - field irradiation. The entire irradiated zone is divided into several fields. The number of fields depends on the area of the defocused laser beam. In one procedure, up to 3-5 fields are irradiated in succession, not exceeding the maximum allowable total exposure area of 400 cm ² (in the elderly 250-300 cm ² ).

Method 3 - scanning with a laser beam. Laser irradiation is carried out by a labile method in circular motions from the periphery to the center of the pathological zone, affecting not only the site of the lesion, but also the healthy parts of the skin, with their capture up to 3-5 cm along the perimeter of the pathological focus.

When appointing a laser procedure, the following must be reflected:

• wavelength and mode of laser radiation generation (continuous, pulsed);
• at continuous mode - output power and energy irradiation (power density of laser radiation);
• for pulsed mode - pulse power, pulse repetition rate;
• localization and number of fields of influence;
• peculiarities of methodical technique (remote or contact, labile or stable technique);
• no exposure time (point);
• total irradiation time per one procedure;
• alternation (daily, every other day);
• total number of procedures for treatment.

It is necessary to take into account age groups, race, sex. It is recommended to conduct laser therapy sessions through an uncoated skin surface, but irradiation through 2-3 layers of gauze is allowed. It is necessary to establish a rational place of influence and an effective dose of radiation. For stationary patients, the laser therapy session can be performed twice a day; for outpatient - once a day. Preventive courses for chronic diseases are carried out four times a year.

Precautions when working with laser equipment.

1. To work with laser therapeutic devices are allowed to persons who have passed the specialization in laser medicine, and after studying the operating instructions for the device.
2. It is forbidden to: switch on the unit when the grounding is disconnected, repair work when the unit is switched on, work with faulty equipment, leave the laser installation unattended.
3. The operation of laser instruments should be carried out in accordance with the requirements of GOST 12.1040-83 "Laser safety", "Sanitary norms and rules for the device and operation of lasers No. 2392-81".
4. The main requirements when working with laser systems are observance of caution and avoidance of direct and reflected laser beams in the eyes: to turn the laser into the "work" mode only after stopping the emitter on the impact zone; It is possible to remove and move the emitter to another zone only after the laser is turned off automatically as a result of the timer operation. During the laser irradiation session, personnel and the patient are required to use special safety glasses.

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