Patent ID: 7979107

Claim:
A method for differentiating malignant in vivo liver tissues from normal in vivo liver tissues of a living subject, comprising the steps of: (a) illuminating a first area and a second area of in vivo liver tissues of the living subject with a first excitation light; (b) measuring an intensity of fluorescent light emitted from the first area of in vivo liver tissues and an intensity of fluorescent light emitted from the second area of in vivo liver tissues in response to the first excitation light as a function of wavelength so as to obtain a first and a second fluorescent spectra of the in vivo liver tissues of the first area and the second area, respectively; (c) illuminating the first area and the second area of in vivo liver tissues of the living subject with a second excitation light; (d) measuring an intensity of diffuse light reflected by the first area of in vivo liver tissues and an intensity of diffuse light reflected by the second area of in vivo liver tissues in response to the excitation light as a function of wavelength so as to obtain a first and a second diffused reflectance spectra of the in vivo liver tissues of the first area and the second area, respectively; and (e) identifying one of the first area and the second area of in vivo liver tissues as malignant liver tissues and the other one of the first area and the second area of in vivo liver tissues as normal liver tissues, by identifying corresponding blood absorption signature through comparing the first fluorescence spectrum of the in vivo liver tissues of the first area and the second florescence spectrum of the in vivo liver tissues of the second area, and comparing the first diffused reflectance spectrum of the in vivo liver tissues of the first area and the second diffused reflectance spectrum of the in vivo liver tissues of the second area, wherein the fluorescence spectrum of the malignant liver tissues shows no blood absorption signature at a first wavelength of about 540 nm and a second wavelength of about 580 nm, and the intensity of the diffused reflectance spectrum of the malignant liver tissues substantially monotonically decreases over a wavelength region from about 620 nm to about 700 nm, and the fluorescence spectrum of the normal liver tissues shows blood absorption signature at the first wavelength of about 540 nm and the second wavelength of about 580 nm, and the intensity of the diffused reflectance spectrum of the normal liver tissues is substantially unchanged over the wavelength region from about 620 nm to about 700 nm, wherein the blood absorption signature in the fluorescence spectrum of the normal liver tissues corresponds to spectral valleys at the first wavelength of about 540 nm and the second wavelength of about 580 nm.