Cholangiocellular cancer (CCC) is an oncological disease of the bile ducts characterized by a high mortality rate.To date,the use of standard methods for the diagnosis and treatment of CCC has not been able to reduce mortality from this disease.This work presents the results of fluorescence diagnostics (FD),which consists in using a modified optical fiber and photodynamic therapy (PDT) using a therapeutic laser instead of a low-intensity laser.This technique was tested on 43 patients in a clinical setting.The results obtained indicate a direct correlation between spectroscopic and video FD methods.Furthermore,a direct correlation was found between the photobleaching of a chlorin e6-based photosensitizer,with the commercial names of Photolon Radachlorin and Photoran and stricture regression.Our findings demonstrate the possibility of using a therapeutic laser with a wavelength of 660 nm for both diagnosis and treatment of bile ducts cancer,which results in a significant reduction of the operation time without decreasing its effectiveness.