Excitation/emission resolved fluorescence imaging with FR-IsoMap

Fluorescence imaging has been demonstrated to be able to detect and diagnose different tumour types in a range of biological tissues including cervix, lung, and along the gastrointestinal tract. An approach based on laser induced tissue autofluorescence may be applied minimally invasively using endoscopes, although there is a high degree of overlap in endogenous fluorophore excitation/emission spectra. This paper presents a tuneable laser induced fluorescence imaging system that is able to increase specificity through simultaneous variation of excitation and emission wavelengths. The method is validated using fluorescent laser dyes with data analysis being performed with fixed reference isomap (FR-IsoMap). The method is compared to principle component analysis (PCA) for dimensionality reduction to demonstrate the improved specificity and sensitivity achieved based on one-way Multivariate Analysis of Variance (MANOVA).