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Detection of epidermoid squamous-cell carcinoma by laser induced autofluorescence – preliminary results
Authors: Romeo Costin, Tatiana Tozar, V. Zainea, Ruxandra Pîrvulescu, I. R. Andrei, R. Hainăroșie
Number of views: 316
Epidermoid squamous-cell carcinoma is by far the most common malignant tumor of larynx
(95-96%), representing 1.6-2% of cancers in men and 0.2-0.4% of malignancies in females, with a
world growing incidence and a slight dominance in urban areas. By exposing cells and tissues to UV
light, the excitation of naturally occurring chromophores occurs in part by non-radiative
deactivations, in part via fluorescence emission. Using laser induced autofluorescence (LIAF) in natural
tissues not impregnated with photosensitizers as a noninvasive autofluorescence technique for both
diagnosis and intraoperative assessments of laryngeal cancer we can improve the tumor malign
identification in vivo. A total of three laryngeal biopsies (i.e. three pairs of tissues, each pair
containing a healthy and a tumor tissue sample extracted from the same patient) were considered in
this study. The samples were collected from patients previously diagnosed with stage T3 laryngeal
carcinoma. Immediately after the surgery fragments of normal tissue and neoplastic tissue were
collected, fragments of which later, after freezing, were sectioned in 25-30 μm thickness slices and
stretched to quartz slides. All samples were subjected to controlled laser irradiation using a pulsed
diode laser (λ=375nm, pulse width=87ps, frequency 31MHz) and the autofluorescence and its lifetime
were collected using two optical fibers (inner diameter 400μm and 1500μm, respectively) positioned
in a 45o geometry. The signals were recorded using a spectrograph and a photo-sensor module, the
output of which was fed to a digital oscilloscope.
We assessed the impact of laser induced autofluorescence and autofluorescence lifetime
measurements in order to identify the differences between healthy and tumoral laryngeal tissue and
outlining them, in terms of differences between the laser autoinduced fluorescence averaged
intensity. The results determined the usefulness of laser induced spectroscopy in the diagnosis of
laryngeal squamous cell carcinoma, discriminating between the malignant and normal tissue by
analyzing the differences in spectral autofluorescence intensity and autofluorescence lifetime.
Acknowledgements: This work has been financed by the National Authority for Research and
Innovation in the frame of Nucleus programme - contract 4N/2016 and the project number PN-II-IDPCE-
2011-3-0922. The authors thank Prof. M. L. Pascu for permanent support in performing this
research.