Confocal fluorescence spectroscopy system for detecting early-stage cancer

Abstract

Diagnostic techniques based on optical spectroscopy have the potential to link the biochemical and morphological properties of tissues. Light-induced fluorescence (LIF) spectroscopy as a noninvasive “optical biopsy” method has been widely used to detect small lesions in vivo . Confocal fluorescence spectroscopy provides a tool for optical sectioning of tissue and provides an approach for identifying small shifts in the emission spectra that are caused by intracellular microenvironment factors. The ability to demarcate abnormal and normal tissue with a confocal spectroscopy system depends on the ability of interpreting the source of fluorescence within the samples. It is realized by spatially dispersing the fluorescence collected with a fiber that serves as the pinhole aperture of the confocal system. In order to tracing the autofluorescence spectral signals of tissue layer by layer, a confocal fluorescent spectroscopy system has been set-up. Experiments have been carried out with fluorescent phantom and animal models. With an axial resolution of 10um in animal tissues, this confocal spectral system observed the spectral differences in spectral shape and spectral peak position among different layers of tissue illuminated with 349nm laser. It was also found that the fluorescence intensity is depth-dependent. In conclusion, confocal fluorescence spectroscopy can provide more diagnostic information due to its ability of optical sectioning. It’s hopeful that a confocal spectral system can detect cancer at much earlier stage.