Optical Techniques: Investigations in Oral Cancers

The routine oral cancer screening involves a clinical oral examination followed by biopsy. The biopsied sample is subjected to histopathology, the gold standard. As this procedure is prone to subjective errors, requires experienced pathologists and is time consuming, it is pertinent to explore newer diagnostic adjuncts/methods. The changes in the biochemical properties of an organ/tissue are also known to be reflected in the optical properties which can be conveniently exploited through optical techniques. Optical techniques are shown to be rapid, objective, and noninvasive and are sensitive to tissue biochemistry. Since biochemical changes often precede visible morphological alterations, these techniques can serve as potential screening/diagnostic tools. This chapter highlights the advancements of optical/spectroscopic techniques, such as fluorescence spectroscopy, elastic scattering spectroscopy, diffuse reflectance spectroscopy, optical coherence tomography, Fourier-transform infrared spectroscopy, and Raman spectroscopy, in the field of oral cancer diagnostics/screening. The chapter begins with discussion on scope of optical techniques and basic principles of these techniques, followed by a brief discussion of multivariate statistical tools which play a major role in data analysis. The last section provides an overview on explorations of optical techniques in oral cancer screening/diagnosis.