Hypericin-induced fluorescence in stomach cancer detection

The fluorescence spectra from stomach mucosa have been measured for cancer diagnostics using hypericin as a photosensitizer. Hypericin was administered orally in amount of 0.1 mg/kg b.w. four hours before conventional endoscopic procedure. Fluorescence was induced by He-Cd laser coupled to optical fiber probe which was inserted into a biopsy channel of the endoscope; the output power at the distal fiber end was 6 mW. Fluorescent light was collected fiber optically and registered by a spectroanalyzer in the range up to 700 nm. Detection algorithm included a comparison of characteristic orange fluorescence of hypericin at 600 nm with fluorescence at 530 nm in conjunction with results of white-light endoscopy. Fluorescence procedure was performed in thirty-seven patients with various oncological and other stomach disorders. It has shown an average 90 percent specificity in detection of small size lesions. Developed technique is promising to detect early stomach cancers and indicate an advantage of laser induced fluorescence with photosensitizer hypericin in differential cancer diagnostics.