In-vivo autofluorescence spectroscopy of bladder carcinoma with a mercury arc lamp

Bladder tissue autofluorescence spectra are obtained in vivo at two excitation wavelengths (334 nm and 365 nm) with a cystoscopic fiber- optic device based on a small mercury arc lamp. Upon 365 nm excitation, both normal and cancerous bladder tissue have nearly identical fluorescence spectra, characterized by a broad peak at 455 nm. However, the fluorescence yield from malignant tissue is approximately a factor 3 lower compared to normal tissue. A similar decrease in fluorescence yield is observed upon 334 nm excitation. More importantly, at this excitation wavelength, the spectra from normal and malignant tissue have different lineshape. Normal tissue shows two distinct fluorescence peaks (at 385 nm and 455 nm), while malignant tissue only shows the 455 nm peak. Based on these insights, we have developed a simple spectroscopic algorithm, to differentiate normal from malignant bladder tissue with our device. The main underlying biophysics will be addressed. The integration of the diagnostic method with a reliable therapeutic technique for tumor cell destruction, may open the way for cost- effective preventive care of high-risk patients.