###### Abstract
D is determined by the product of illuminating a biological object (wound) I\({}_{\Delta\lambda}\) (in W/cm\({}^{2}\)) in a given \(\Delta\lambda\) for a given exposure time (t (s)); i.e., D = I\({}_{\Delta\lambda}\cdot\)t. In clinical practice, the basis for UV radiation dosimetry is the minimum erytmal dose (MED)--the lowest energy dose of skin irradiation (in mJ/cm\({}^{2}\))--which causes minimal-intensity erythema but with clearly defined boundaries. The MED is determined individually, using biodosimeters [4; 20]. According to international recommendations, the MED for sensitive skin is 25 mJ/cm\({}^{2}\)[22]. The sensitivity of microorganisms to UV radiation varies widely depending on the species and their condition: for vegetative bacteria, the ability to form colonies is suppressed by 90% at doses of UV-C radiation (with a wavelength of \(\lambda\) = 254 nm) from 1.1 to 8 mJ/cm\({}^{2}\); the doses required to reduce the bacterial load by four decimal orders are therefore in the range of 5...20 mJ/cm\({}^{2}\)[19]. At the same time, Gram-positive bacteria, as a rule, are more resistant to UV radiation than Gram-negative ones. The doses for the inactivation of pathogens on living tissue are increased due to the peculiarities of the surface condition of living tissue. The use of optical technologies in medicine has a long history. The most active research and development period for optical technologies (in particular, ultraviolet) was in the 1930s and 1940s. During these years, practical medicine did not yet know about antibiotics, and many scientists pinned their hopes on ultraviolet light for significant progress in treating tuberculosis, purulent-inflammatory diseases, and infectious diseases. Extensive experimental material on the bactericidal and therapeutic effects of UV radiation was collected, and many preventive and therapeutic methods for the clinical application of ultraviolet radiation were developed [17]. These methods, practically unchanged since then, are still recommended for use at present [4; 20; 23; 24; 25]. However, with the advent of antibiotics, interest in UV-based medical technologies for treating wounds has notably weakened. Another factor constraining the widespread introduction of UV therapeutic technologies is the risk of possible long-term side effects due to UV irradiation, such as carcinogenesis, which may occur with inadequate methodological applications of such technologies [3; 17; 21]. The \"crisis of antibiotics\" became acute at the beginning of the 21 st century, forcing medical specialists to reconsider the current paradigm of UV radiation for medical use [3]. In [21], the authors proposed a therapy using short-wave UV-C radiation as an alternative approach to the current treatments for localized infectious diseases, especially those caused by pathogens with multidrug resistance. Prospects for using UV-C therapy to treat wounds are associated with several factors, among which, the following are primarily noted:  
* Multidrug-resistant microorganisms are equally sensitive to UV irradiation as their \"wild-type\" counterparts [21; 26; 27];
* UV-C radiation destroys microorganisms much faster than antibiotics--hours with UV-C therapy versus several days with antibiotic treatments [3; 21];
* UV-C therapy could be much more cost-effective than commonly used antibiotics. This is because, in addition to inactivating microorganisms, adequate exposure to short-wave UV radiation promotes accelerated wound healing and restores skin homeostasis. The effects of UV-C radiation on wound healing include hyperplasia and enhanced re-epithelialization, granulation tissue formation, and the shedding of necrotic tissue [3; 21; 28]. In [3], in an analysis of the potential of UV-C technologies, low-pressure mercury lamps with various types of excitations, excimer lamps, and short-wavelength LEDs were considered as sources of UV radiation.