Abstract. Our results suggest that the combined use of optical coherent tomography (OCT) and fluorescence diagnosis helps to refine the nature and boundaries of the pathological process in the tissue of the colon in ulcerative colitis. Studies have shown that an integrated optical diagnostics allows us to differentiate lesions respectively to histology and to decide on the need for biopsy and venue. This method is most appropriate in cases difficult for diagnosis.

Our results suggest that the combined use of optical coherent tomography (OCT) and fluorescence diagnosis helps to refine the nature and boundaries of the pathological process in the tissue of the colon in ulcerative colitis. Studies have shown that an integrated optical diagnostics allows us to differentiate lesions respectively to histology and to decide on the need for biopsy and venue. This method is most appropriate in cases difficult for diagnosis.

In the up-to-date medical laser fluorescence spectroscopy (LFS) in vivo, there is a problem of quantification of fluorophores concentrations in optically-turbid biotissues by measurements of the laser induced autofluorescence flux on the surface of these tissues. One of the main problems is: whether the flux depends linearly or non-linearly on the concentration of fluorophores in tissues? The purpose of this work was both experimental and theoretical study of the character of dependencies between measured fluorescence intensities and fluorophores concentrations in optically-turbid media. In the experimental part of our study, measurements of the superficial fluorescence on phantoms at various known concentrations of fluorophores in them were carried out. As a result, experimental dependencies of registered intensities of the laser-induced autofluorescence emission were plotted against fluorophore concentrations. In the theoretical part of the study, the analytical solution for the fluorescence emission by Kokhanovsky's method based on the well-known two-flux Kubelka-Munk approach (KMA) was used. In addition, in our study the Kokhanovsky's method was modified by its association with our improved KMA, allowing us to receive exact analytical solutions for boundary intensities collected by optical probes. As a result, a set of theoretical curves describing the influence of fluorophore concentrations on the registered autofluorescence intensities was obtained, as well. Both experimental and theoretical results show a good qualitative agreement with each other. Also, these results demonstrate that the dependence of the fluorescence intensity on tissues' optical properties and on the concentration of fluorophores in light-scattering tissues can be both nonlinear and non-monotonic.

Many researchers during past 20 years have used the laser fluorescence spectroscopy (LFS) for in vivo tissue diagnosis. But in the up-to-date medical in vivo LFS there is a problem of quantification of the fluorophores concentrations in optically-turbid biotissues basing on measurements of the laser induced fluorescence on a surface of the tissues. The purpose of our work is both experimental and theoretical study of the character of dependences of measured fluorescence intensities on tissues' optical properties and on fluorophores concentrations in tissues. In the experimental part of our study the measurements of the superficial fluorescence on phantoms at different known concentration of fluorophores in them were carried out. As a result experimental dependences of the registered intensities of the laser induced fluorescence emission on fluorophores concentration were plotted. In the theoretical part of our study the analytical solution for a fluorescence emission by Kokhanovsky's method based on the well-known two-flux Kubelka-Munk approach (KMA) was used. Besides, in the study the Kokhanovsky's method was modified by its association with our improved KMA, allowing us to receive exact solutions for boundary intensities collected by an optical probe. As a result a set of theoretical curves describing the influence of fluorophore concentration in tissues on the registered intensities was obtained as well. Both experimental and theoretical results show a good qualitative agreement between each other. Also these results show that the dependence of the fluorescence intensity from tissues' optical properties and from the concentration of fluorophores can be both nonlinear and non-monotonic.

Early results of complex experimental investigations on the study of instrumental and methodological errors of diagnostics in noninvasive medical spectrophotometry are described. Physical and technical sources and factors of errors are considered for measurements using nonbiological simulation measures. It is shown that the geometric and spectral characteristics of the optical elements and photodetectors, and also selected models and data-processing algorithms in the computer software of the instruments, have the greatest effect on the diagnostic errors.

Early results of complex experimental investigations on instrumental and methodological errors of diagnostics in noninvasive medical spectrophotometry are described. Medicobiological sources and factors of errors are considered for natural measurements under clinical conditions. It is shown that the greatest contribution to the total measurement error is made by the interactive component, due to the interaction of the measurement instruments and objects.

Surgical treatment of 11 patients with malignant cerebral gliomas was implemented under visual neuronavigation. Surgery planning was accomplished at the Medtronic Navigation Station (Stealth Station Treon Plus) to achieve optimal surgical approach, encephalotomy, and tumor localization. Probe spectrophotometry fluoronavigation was used in two cases to demarcate tumor tissue border. Application of the combined neuronavigation in surgical treatment of cerebral tumors allows verification of tumor border and completeness of its removal while holding the principles of low-invasive surgery.

The first steps in systematization and analysis of the most fundamental and specific metrological terms, concepts, and definitions applicable to noninvasive medical spectrophotometry (NMS) are discussed. An operational approach to the metrology for the purpose of creation and development of fully functional metrological support of NMS is suggested. Some key properties and aspects of optical in vivo measurements in NMS are discussed. Fabrication of simulation measures and introduction to NMS theory and practice of the notion of diagnostic volume of biological tissues are established as well.

This paper describes a new multifunctional laser noninvasive diagnostic system (MLNDS) for medicine. In a single hardware MLNDS combines 3 different in vivo laser diagnostic techniques: Laser Doppler Flowmetry, Laser Fluorescent Diagnostics and Reflectance Tissue Oximetry. All these methods together allow a doctor to evaluate more exactly and in vivo a functional condition of soft tissues, especially to study the finenesses of respiratory and blood microcirculation processes in a skin and mucosa. The complex complementary diagnostics turns out to be more powerful than a trivial sum of isolated one. To produce more precise measurements a number of problems of metrological providing for that have been studied as well as a set of simple, reproducible and photostable calibration gauges with tissue-like optical properties has been created.

The article proposes a strict definition of the notation of "diagnostic volume" (DV) in a modern medical in vivo spectrophotometry. Theoretical description of a calculation algorithm to evaluate DV with the use of exact modified one-dimensional Kubelka-Munk approach is proposed as well. In a general case, numeric calculations show that for typical human soft tissues effective DV in the simplest one-dimensional theoretical case is lying in a range of 1-8 ram of a depth of the both scattering and absorbing medium.

Paper discusses an accuracy, reliability and reproducibility of "in vivo" laser fluorescent diagnostics (LFD) in medicine. Modern equipment and calibration standards for LFD are discussed as well. It is shown, that, in spite of the fact that formal random errors of "in vivo" instantaneous fluorescent measurements have been previously evaluated on a level of 30-40%, the medical accuracy and reliability of LFD could reach a quite high and informative level. Most of the formal "random" disperses in results of the single "snapshot" measurements are associated with a changeable and alive character of the object of diagnostics.

Based on an analysis of various clinical data, the assumption was recently expressed that the often observed in vivo increased fluorescence of endogenous porphyrins in living biological tissues is a consequence of the status of chronic hypoxia in the tissues. Starting from this, this article discusses the accuracy, reproducibility, and information content of methods of in vivo laser fluorescence diagnosis (LFD) in actual clinical practice. It is shown that, despite the random error of single measurements in LFD of 30–40% established earlier, the accuracy and reliability can reach a fairly high level when the results of the diagnosis are interpreted. The formal random scatter in the results of single measurements is largely determined not by the instrumental error but by the methodological error and by the living and changeable character of the object of diagnosis, especially at the level of the blood-microcirculation system.

For higher efficacy of early gastric carcinoma diagnosis by endoscopy, the authors suggest a method of autofluorescent diagnostics. It is based on the property of endogenous porphyrins conteined in the tumor to emit light under the effect of laser. The suggested method was used in examination of 311 patients (gastric ulcer 176, polyps 135). It is shown that the method of autofluorescent diagnostics may be applied in cases which are difficult for diagnosis.

The Kubelka-Munk (KM) two-flux light transport one-dimensional (1D) model is, evidently, the most widely used transport theory in biomedical optics because of its simplicity and existence of its clear analytical solution. Moreover, the KM approach is a good approximation of the general radiative transport equation in the case of 1D theoretical tasks. But it is well known that the KM model doesn't allow anyone to obtain an exact solution, especially in cases of highly-absorbing and weakly-scattering media. In the most of publication it is assumed that the light must be diffuse on a surface as well as within the medium for a correct application of the KM equations. However, in our opinion, there is no any reason to separate light radiation on diffuse and collimated components in a simple 1D theoretical model. So, the root of the problem of the model accuracy may be located in a far another field. As we reported in our previous publications more correct results with the use of KM basic approach in some special cases of turbid media can be yielded by means of some modification of original KM equations. In this work we propose a general improvement of 1D two-flux KM model for any cases of scattering and absorbing media to reach an exact analytical solution of any theoretical 1D light propagation and scattering problem in application to biomedical noninvasive reflectance spectroscopy.

The article covers results of application of biospectrometry-based endoscopy with low-intensive He-Ne laser radiation in complex therapy of torpid esophageal, gastric, and duodenal ulcers. The authors are the first to offer a method based upon individual biophotometric control (autofluorescence, oxigination), which allows verification of the ulcerous process character, individual optimization of treatment and objective control of ulcer regression.

Different aspects of optic invasion-free diagnostics in medicine are under discussion. The diagnostic possibilities of the method as well as the principles of its equipment-related and methodological realization are briefly analyzed. A conclusion is made on a unified optic invasion-free diagnostic technology in medicine and on its similarity to the general methods of laboratory spectrophotometry. Therefore, the designing of universal diagnostic complexes combining various diagnostic techniques on the bases of common diagnostic equipments is the most promising trend in developing the appropriate outfit for the diagnostic sphere.