Most cervical cancers originate from the epithelial layer by an uncontrolled growth of abnormal squamous cells and are known as carcinomas. Early stages of this disease manifest as biochemical and morphological changes in the superficial layer. Such changes can be captured from the spectral behavior of intrinsic fluorophores present in the layered cervical tissue. Fluorescence spectroscopy is thus widely used for detection of pre-cancers, also due to its capability as a fast, non-invasive and quantitative probe. This study focuses on analysis of the spectral information of the fluorophores using spatially resolved fluorescence spectroscopy for diagnosis of cervical cancer at an early stage. An in-house fabricated fiber-optic probe of diameter 1mm, consisting of 77 fibers in approximately five circular rings with very high sensitivity for superficial layer changes, has been used to collect fluorescence spectra from different spatially resolved positions of two layered solid phantoms. The phantoms are prepared by varying the thickness and fluorophore concentration of the upper layer. Optical properties of these layered phantoms have been kept similar to cervical tissue to replicate the subtle changes that occur in the tissue with the growth of abnormality. A 405 nm laser diode source is used to excite the samples with two different fluorophores in the two layers, Flavin Adenine Dinucleotide (FAD) in upper layer and Proto-porphyrin (PpIX) in bottom layer. A `Look-up Table' method is used to finally reconstruct thickness and fluorophore concentrations of upper layer of an unknown phantom by evaluating the peak ratios of fluorophores from spectra obtained at different spatially resolved positions.
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