Optical techniques have the potential for performing in vivo diagnosis on tissue. Spectral characteristics of the components provide useful information to identify the components, because different chromophores have different spectroscopic responses to electromagnetic waves of a certain energy band.
The basis for this mapping method arise from the differences in the spectra obtained from the normal and diseased tissue owing to the multiple physiological changes associated with increased vasculature, cellularity, oxygen consumption and edema in tumour. Different skin and sub-surface tissues have distinct or unique reflectance pattern which help us differentiate normal and cancerous tissues.
An optical fibre spectrometer is set up for this purpose, which is safe, portable and very affordable relative to other techniques. The method involves exposure of skin surface to white light produced by an incandescent source. These back scattered photons emerging from various layers of tissue are detected by spectrometer resulting in tissue surface emission profile.
For the present study, three different skin diseases-warts, moles and vitiligo are chosen. The spectral data from the scan is presented as a multi-wavelength plot. Further, ratio analysis is carried out in which, the relative spectral intensity changes are quantified and the spectral shape changes are enhanced and more easily visualized on the spectral curves, thus assisting in differentiating the part which is affected by disease visually.
The unique information obtained from the multiwavelength reflectance plots makes it suitable for a variety of clinical applications, such as therapeutic monitoring, lesion characterization and risk assessment.