By now it is firmly established that the low-intensity laser radiation (LILR) of visible and near infrared spectral regions has a high biological activity of regulator character. It is shown that LILR is one of the most efficient physiotherapeutic means of a wide action spectrum. Its use in complex therapeutic technologies allows to improve essentially the effectiveness of treatment of many diseases practically from all divisions of medicine

(e.g., such as long-term green wounds and ulcers, burns, fractures of bones, wounds after surgical operations, degenerative and dystrophic diseases of the supporting and motive organs, chronic prostatitis, syphilis, eczema, herpes, acute and chronic bronchitis, consequences of insults of all etiologies, ishemiac heart disease, polyneuritis of the various origins and many others).

For achievement of therapeutic effect the impact of LILR is applied to affection seats:

• on surface of human body • to intracavitary localization of affection seats via endoscope with the use of monofilament fibers • to blood (intravenous and overvenous irradiation) • to projection of internal organs on coverlet • to biologically active points.

It should be noted that investigations and developments in the field of laser therapeutic technologies are intensively developed not only in the Republic of Belarus but in such countries as Russia, Italy, China, Japan, Germany, England, USA and other countries.

In the Republic of Belarus the investigation of regulator biological activity of LILR and therapeutic efficiency of mentioned physical factor, development of efficient laser therapeutic technologies on the basis of its application and corresponding laser therapeutic devices are carried out for many years at B.I. Stepanov Institute of Physics of the National Academy of Sciences together with Belorussian State Medical University, Belorussian State Academy of Postgraduate Medical Training, Institute of Physiology of the National Academy of Sciences, Institute of Neurology, Neurosurgery and Physiotherapy of Ministry of Health of the Republic of Belarus and others.

As a result of these investigations the basic rules of LILR action on somatic cells of animals and human have been found out. Cells are the basic structural and functional units of multicellular organisms (animals and human). It is known that practically any pathology of an organism is connected to dysfunctions of cells. One of the most important functions of cells is mitosis (division). Mitosis defines rate of growth and regeneration of tissues of an organism, activity of immune system and others. Other very important function of cells is the recovery of the damaged molecular structures of their genetic apparatus (chromosomes).

It is proved that linearly-polarized LILR is capable to have a regulator not damaging action on functional (mitotic, biosynthetic, recovery of damaged chromosomes) activity of animal and human cells both in vitro conditions (in culture of cells) and in vivo conditions (in tissues of a body of an organism). It is experimentally observed the change in activity of the major enzymes of a metabolism, rate of synthesis of enzymes, DNA, RNA, permeability of cellular membranes, rate of cellular division, recovery of their damaged chromosomes, regeneration of tissues, activity of immune system as defines therapeutic effect.

It is established that only polarized (better linearly-polarized) LILR causes the change in functional activity of cells. The size of effect of LILR action on functional activity of cells as well as direction of its change towards increment or decrement depend on power density of acting radiation at the zone of action and time of its (radiation) action. It is shown that polarized low-intensity radiation of superbright light-emitting diodes (LEDs) is characterized by a biological activity and therapeutic efficiency comparable with biological activity and therapeutic efficiency of polarized LILR. The nonpolarized radiation of the given sources as well as nonpolarized LILR don’t possess biological activity and don’t have therapeutic action.

The aforementioned facts confirm the conclusion made by authors of development of therapeutic devices presented below that the photophysical process determining biological activity and therapeutic efficiency of LILR is its nonresonant interaction with the definite molecular structures of cells (orientational interaction, interaction between dipoles induced by LILR) but not absorption of its quanta. It is supposed that such molecular structures can be domains of protein-enzyme molecules and membranes of cells.

It is also established that in the case of action by non-dispersed laser beam (local action, diameter of irradiated surface is 2 – 3 mm) on a surface of monolayer of cells on cover glass or on tissue of animal and human body the changes caused by beam is generalized on the extensive adjacent area which was not subjected to irradiation. This effect allows using in laser therapeutic technologies the action on lesion focus on human body by non-dispersed laser beam with small diameter and small angular divergence in several local zones. Clinical tests of such therapeutic technology have shown its higher medical efficiency in comparison with a variant of action by the same beam dispersed on all zone of lesion focus.

The experimental investigations on cellular and organism levels have shown that the stimulating and as a consequence therapeutic effects raise considerably at combined action by LILR originally blue and then red regions of spectrum of electromagnetic waves.

In addition to given method one more opportunity of increase of therapeutic effect of LILR is experimentally proved, it consists in use of simultaneous influence of LILR and a weak magnetic field in technology of treatment.

The modern laser therapeutic on the basis of stationary (power up to 500 mW), pulse-periodic (average power up to 20 mW), semiconductor lasers and superbright light-emitting diodes by power up to 15 mW are developed and produced at the Institute of Physics of the National Academy of Sciences of Belarus together with Research-and-Production Company «Luzar» and the Design Bureau «Axicon» for realization of therapeutic effects of low-intensity laser radiation in medical practice.

The beam with small diameter, small angular divergence and sufficiently high power density (on section) allows providing the parameters of acting radiation (power density, a degree of polarization) necessary for reception of therapeutic effect on the essentially greater depth in strongly scattering human tissue.

The laser therapeutic devices under review provide use of the combined influence on lesion focus with radiation of blue and red regions of spectrum; near infrared and red regions of spectrum; blue, red and infrared regions of spectrum as well as joint action of laser radiation and a constant magnetic field in therapeutic technologies.