Biophysics, Invited Lecture


Ekaterina Borisova, Aleksandra Zhelyazkova, Latchezar Avramov, Institute of Electronics, Bulgarian Academy of Sciences, 72, Tsarigradsko chaussee Blvd., 1784 Sofia, Bulgaria
Elmira Pavlova, Petranka Troyanova, University hospital “Queen Jiovanna-ISUL”, 8 Bialo more str., 1527 Sofia, Bulgaria
Todor Kundurjiev, Faculty of Public Health, Medical University-Sofia, 8, Bialo more Str., 1527 Sofia, Bulgaria


We investigated more than 500 clinical cases to receive the spectral properties of basal cell (136 patients) and squamous cell carcinoma (31), malignant melanoma (41) and different cutaneous dysplastic and benign lesions. Excitation at 365, 385 and 405 nm using LEDs sources is applied to obtain autofluorescence spectra, and broad-band illumination in the region of 400-900 nm is used to detect diffuse reflectance spectra of the cutaneous pathologies investigated. USB4000 microspectrometer (Ocean Optics Inc, USA) is applied as a detector and fiberoptic probe is used for delivery of the light.
In the case of in vivo tumor measurements spectral shape and intensity changes are observed that are specific for a given type of lesion. Autofluorescence origins of the signals coming from skin tissues are mainly due to proteins, such as collagen, elastin, keratin, their cross-links, co-enzymes – NADH and flavins and endogenous porphyrins. Spectral features significant into diffuse spectroscopy diagnosis of different cutaneous tumours are related to the effects of re-absorption of hemoglobin and its forms as well as melanin and its concentration in different pathologies. The spectral features in both spectroscopic modalities used depend from the lesion type and growth stage of the tumor and could be applied for differentiation algorithms and cancer diagnosis. Based on our results, we develop significant database and revealed specific features for a large class of cutaneous neoplasia, using about 30 different spectral peculiarities to differentiate cutaneous tumor and to evaluate the diagnostic accuracy, when optical spectroscopy of skin is applied in clinical environment. Sensitivity and specificity obtained exceed 90%, which make optical biopsy very useful tool for clinical practice.
This report generalized our four-year efforts on accumulation and development of autofluorescence and diffuse-reflectance spectral database for skin cancer diagnosis and differentiation for clinical practice, formatting optical biopsy method for initial skin cancer detection. The results are obtained in the frames of clinical investigations for development of significant “spectral features” database for the most common cutaneous malignant, dysplastic and benign lesions.
Acknowledgements: This work is supported by the National Science Fund of Bulgaria under grants #DO-02-112/2008, #DMU-03-46/2011 and under personal fellowship of E. Borisova from Foundation UNESCO/L’Oreal “For young women in life sciences”, Bulgaria - 2014. Experimental results will be used as well for the needs of COST Action BM1205 "European network for skin cancer detection using laser imaging"

Representing author


Dr. Ekaterina Georgieva Borisova

Institute of Electronics, Bulgarian Academy of Sciences, Associate Professor
Sofia, Bulgaria

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