Biophysics, Invited Lecture

ENDOGENOUS AND EXOGENOUS FLUORESCENCE SPECTROSCOPY OF GASTROINTESTINAL TUMORS – IN VITRO AND IN VIVO INVESTIGATIONS

E. Borisova, L. Angelova, Ts. Genova, Al. Zhelyazkova, L. Avramov, Institute of Electronics, Bulgarian Academy of Sciences, 72, Tsarigradsko chaussee Blvd., 1784 Sofia, Bulgaria
M. Keremedchiev, B. Vladimirov, University hospital “Queen Jiovanna-ISUL”, 8 Bialo more str., 1527 Sofia, Bulgaria

ABSTRACT

The limitations of standard endoscopy for detection and evaluation of cancerous changes in gastrointestinal tract (GIT) are significant challenge and initiate development of new diagnostic modalities. Therefore many spectral and optical techniques are applied recently into the clinical practice for obtaining qualitatively and quantitatively new data from gastrointestinal tumours with different level of clinical applicability and diagnostic success. Fluorescence imaging has been one of the most promising technologies in this area. The technique is very topical with its practical application in intra-operative, image-guided resection of tumors, because it permits minimal surgery intervention and friendly therapeutic conditions.
Investigations presented here are based on in vitro measurements of excitation-emission matrices (EEM) for GIT neoplasia and in vivo measurements in the frames of initial clinical trial for tumor fluorescence spectra detection, applied for introduction of spectroscopic diagnostic system for optical biopsy of GIT tumors in the daily clinical practice of University Hospital “Queen Giovanna - ISUL”- Sofia.
For in vitro cancer fluorescence spectroscopy measurements the FluoroLog 3 system (HORIBA Jobin Yvon, France) is used. It consists of Xe lamp (200-650 nm), scanning double monochromators, and PMT detector with high performance in the region 200-800 nm.
For in vivo fluorescence measurements of gastrointestinal pathologies excitation sources at 405, 530 and 630 nm are applied. As exogenous fluorescent marker 5-ALA/PpIX is used. It is orally applied, as a water solution (20 mg/kg dose), 6 hours before measurement.
Autofluorescence and exogenous fluorescence signals are detected from normal mucosa, inflammation, dysphasia and carcinoma and main spectral features are evaluated. The systems and methods developed for diagnosis and monitoring could open new dimensions in diagnostic and real-time tumor resection. This will make the entire procedure more personal, patient friendly and effective and will help for further understanding of tumors nature.
Acknowledgements: This work is supported by the National Science Fund of Bulgarian Ministry of Education and Science under grant #DMU-03-46/2011 “Development and introduction of optical biopsy for early diagnostics of malignant tumors”

Representing author

photo

Dr. Ekaterina Georgieva Borisova

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

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