Transitional bladder cell carcinoma (TCC) is easily recognizable, but for the diagnosis of severe dysplasia and carcinoma in situ (CIS) one can only rely on randomly taken biopsies. Fluorescence tagging of tumors by sensitizing agents such as hematoporphyrin derivatives (HpD) is possible but presents, even at low doses, a number of serious drawbacks for the patient. We demonstrate a cystoscopic fiber optic instrument, based on a small mercury arc lamp, for in vivo demarcation of human bladder carcinoma. The instrument detects the tissue autofluorescence upon UV excitation (365 nm), thus eliminating the need for sensitizing agents. The average demarcation contrast obtained for CIS and TCC is respectively 2.6 and 3.2, which is about 60% higher than what can be expected from photodynamic imaging with low-dose HpD. The main underlying biophysics are derived from a spectral analysis of the observed autofluorescence signals. The integration of the diagnostic method with a reliable therapeutic technique for tumor cell destruction, opens the way for cost-effective preventive care of high-risk patients.
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