LASER INDUCED FLUORESCENCE OF SKIN: SUPERPOSITION OF SPECTRAL INTENSITIES.

The aim of the work was to determine the possibility of assessing the state of human health by the method of optical spectroscopy of skin and nail. To achieve this goal, Laser-Induced Fluorescence (LIF) spectroscopy was used. A special probe was designed, which makes it possible to record differential spectra and, as a result, to compare the shapes of spectral fluorescence lines. In vivo spectra of LIF intensities of the human finger pad and nail were measured. These spectra can be used to determine and characterize the state of human health, and it's also further monitoring in real time.When processing the spectra of different volunteers, it was found that the fluorescence spectra of the skin of physiologically healthy and pathological (in this case, type 1 and 2 diabetes) volunteers significantly differed from each other. Moreover, the analysis of these spectra makes it possible to assess the degree of pathology. It was also found that any of the three experimentally recorded fluorescence spectra is a superposition of the other two. A theoretical analysis of the multilayer model of human skin fluorescence has shown that this principle is always valid when the same chromophores are involved in fluorescence.

Optical spectroscopy of parotid gland in case of adenopathy.

Reflectance and laser induced fluorescence spectroscopies were employed for the first time in a limited pilot study to probe freshly excised human parotid tissues (adenomatous and adjacent). In human parotid tissue, measurements were associated with endogenous fluorophores NADH and collagen, as well as tissue optical properties, with larger relative collagen content detected from normal to adenomatous tissues. The observed significant differences between the fluorescence and reflectance properties of normal, and adenomatous tissues present an opportunity for future statistical validation on a larger patient pool and indicate a potential application of multimodal optical spectroscopy to differentiate between pathological and normal parotid tissue states at different stages of disease.

Study of distribution of the vitamin A after overdose feeding along the digestive tract of rats intestine by LIFS.

UNLABELLED: Distribution of vitamin A after overdose feeding along the digestive tract of rat's intestine was studied by LIFS. Purpose of our pilot study was to investigate possible usage of LIFS for real time monitoring of vitamin A digestion and storage in intestine as in liver and to identify regions of intestine where vitamin A droplets are formed. ANIMALS: normal male Wistar rats (250-300 g, n=5) were fed on vitamin A enriched diet during the experimental 21 days' period (totally -82.56 mg. vitamin A). The control group (250-300 g, n=5) was maintained by ordinary diet. All rats used in our studies were sacrificed in the morning between 9:30 and 11:30 a.m. Liver and intestinal regions of duodenum, jejunum, ileum and cecum were examined in this experiment. LIF spectra in all parts of intestine as well as in liver demonstrates characteristic fluorescence peaks at approximately 390 nm and at 470 nm. It is clearly demonstrated, that after overdose feeding rats on vitamin A, retinol-rich regions can be found in all, but in cecum part of rat intestine. Obtained results demonstrate that LIFS can be used for study of metabolism and real-time monitoring of intratissue retinol.

Laser therapy by noncoherent light field of radiation.

Conducted researches on study of interaction of radiation with blood have shown, that the interaction is the most effective for light with wavelengths in the range of 600-1000 nm that corresponds to the minimum absorption factor of the whole blood. Calculations show, that at interaction of radiation with blood considerably grows effective (electronic) temperature of biological environment, that results in sharp increase of speed of biochemical reactions. The absence of necessity of application of laser radiation coherence in lasertherapy permits to create high efficient noncoherent sources of light on the basis of the GaALAs(Zn) crystals, radiating with two maxima of wavelengths 675 and 900 nm. The radiation spectrum of GaALAs(Zn) crystals falls in the most favourable area of a blood absorption spectrum.