FEW-FTIR spectroscopy applications and computer data processing for noninvasive skin tissue diagnostics in vivo

New applications for the Fiberoptic Evanescent Wave Fourier Transform Infrared (FEW-FTIR) method have been developed for the diagnostics of skin surfaces. Our technique allows for the detection of functional groups in the molecular structure of skin tissue nonivasively and in vivo. The FEW-FTIR spectroscopic method is direct nondestructive, and fast. Our optical fibers for the middle infrared (MIR) range are nontoxic, nonhygroscopic, flexible, and characterized by extremely low losses. This combination of traditional FTIR spectroscopy and advanced fiber technology has enabled us to noninvasively investigate normal and cancerous skin tissue in vivo in the range of 900 to 4000 cm(-1). We have developed a special software package of programs with database for the treatment of spectral data that utilizes wavelet analysis, principal component analysis (PCA), image processing, artificial neural fuzzy logic, and data fusion. These programs provide us with the ability to make base line corrections, normalize spectra, and determine peak positions from second order derivative spectra. In this study, we investigated normal, precancerous, and cancerous skin tissue in the range 1480 to 1800 cm(-1) using these programs. The results of our surface analysis of skin tissue are discussed in terms of spectral parameters, DNA band assignments, and molecular structural similarities and differences.