Method and Apparatus for Fluorescence Imaging of Tissue
Patent Information:
Filing Country: USA
Application No: 09/420807
Filing Date: 19 October 1999
Patent No: 6343228
Issue Date: 29 January 2002
Inventor 1: Prof. Jianan, QU

A novel endoscopic imaging system for diagnosis of early cancer is described. Optical spectroscopy has been widely used in chemical analysis of biological samples. Since the mid-80s, the use of this technology for tissue classification has become a new approach in non-invasive medical diagnostics. Human tissue is a kind of turbid media in which propagating light are absorbed and highly scattered. Traditional systems can only detect advanced stage cancers that cause obvious change of tissue surface. The new system combines fluorescence and cross-polarized reflection to distinguish diseased tissue from normal tissue for early cancers. Spectral characteristics of endogenous tissue fluorescence (autofluorescence) induced by low power excitation source can partially reveal the physiochemical composition and morphology of tissue, and fluorescence spectrum and intensity is related to tissue chemical composition and morphology. Fluorescence yield of early lesions is lower than that of the normal tissues that surround them. Results of many investigations demonstrated that it is feasible to discriminate lesion, especially for early lesion, from normal tissue by comparing the characteristics of autofluorescence. The current invention will be able to reveal early cancer, especially pre-malignant lesions that are completely invisible by commercially available techniques.
Potential Application   Advantage
- Endoscope in relation to detecting early cancer or diseased tissue   Traditional white light endoscopy can only detect advanced stage cancers that cause obvious change of tissue surface. The sensitivity and specificity for flat and pre-malignant lesions are very low and unacceptable.

The new invention, a combination of fluorescence and polarization imaging of tissue, provides the information of chemical composition and morphology of tissues. It solves the problem to distinguish flat and early lesions from surrounding normal tissues.
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