E. Borisova1,2, Ts. Genova-Hristova1, Al. Khorovodov2, I. Agranovich2, A. Terskov2,
V. Mantareva3, I. Angelov3, N. Navolokin4, O. Semyachkina-Glushkovskaya1
1Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko chaussee Blvd., 1784 Sofia, Bulgaria
2Saratov National Research State University, 83 Astrachanskaya str., 410012 Saratov, Russia
3Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences,
9 Acad. G. Bonchev Blvd., 1113 Sofia, Bulgaria
4Saratov State Medical University, 112 Bol'shaya Kazach'ya str., 410012 Saratov, Russia
The fluorescence detection is pointed as one of the most promising modalities for improvement of the gastrointestinal tract (GIT) diagnostics in clinical practice. This type of detection is mainly divided on autofluorescence and exogenous fluorescence modalities for GIT tumour visualization and differentiation vs. normal mucosa according to the application of endogenous or exogenous fluorescent contrast agents used.
Cancerous tissue alterations affect the light propagation, the absorption properties, and the fluorophores’ content in the tissues, to which parameters the fluorescence spectroscopy is sensitive. The fluorescence intensity and spectral shape, the emission peak positions of endogenous fluorophores, such as tryptophan, tyrosine, collagen, NADH and FAD, hold diagnostic values, whose better understanding and evaluation are necessary for successful implementation of the fluorescence diagnostic into the clinical practice. Autofluorescence spectroscopy is one of the most intensively researched optical techniques for an add-on modality to endoscopic gastrointestinal diagnostics in its steady-state regime of detection.
The one of the significant drawbacks in comparison and evaluation of diagnostic accuracy of autofluorescence technique for gastric tumour detection is the lack of comparison with the spectral data, not only between images obtained. However, the low-level fluorescence intensity do not allow to achieve high-contrast images and a moderate diagnostic accuracy is obtained.
To increase the obtained contrast between normal and abnormal mucosa, exogenous fluorophores, such as different photosensitizing agents (porphyrins, phthalocyanines), are proposed to be used, which could dramatically increased the diagnostic accuracy obtained. The influence of different carcinogenic factors also has been investigated using spectroscopic modalities, to obtain appropriate picture of the spectral changes occurred, which could be correlated to the lesion stage and severity of the pathology detected.
Acknowledgements: This work was carried out in the frames of project DNTS/Russia 01/7-23/06/2017 “Development of new optical technologies for improvement of diagnostics quality of gastric cancer”.
Dr. Ekaterina Georgieva Borisova
Institute of Electronics, Bulgarian Academy of Sciences, Associate Professor
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