Development of an optical system for the detection of oral cancer using near-infrared spectroscopy

A system was developed using a Fourier Transform spectrometer to investigate spectral differences between malignant, benign and healthy oral tissue in the near-infrared range (2.0-2.5 microns). A hamster model for oral squamous cell carcinoma and one for benign lesions in soft oral tissue (i.e. inflammation) was used. After tissue transformation in the malignant and benign cases and when no transformation occurred (i.e. healthy), the animals were euthanized and the cancerous as wed as the normal tissue were excised. Infrared absorption spectra of the buccal mucosa were then collected on all three models, in vitro. A total of 160 near-infrared (NIR) scans were taken, 70 on malignant tissue, 20 on benign, inflamed, tissue and 70 on healthy tissue. Multiplicative signal correction (MSC), used during preprocessing, together with principal component analysis (PCA) showed a 90% sensitivity, 87% specificity and a false negative rate of .10 between malignant and healthy/benign tissue types across animals using this wavelength range. The results of the PCA analysis indicated that differences were detectable in the 2.25-2.35 μm range absorption bands in this range are due to the N-H stretching, C=O stretching vibration, and C-H deformation vibrations