FLUORESCENCE BRONCHOSCOPY FOR DETECTION OF LUNG-CANCER

A system using the fluorescence bronchoscope has been designed for localization of small, early bronchogenic carcinoma by the fluorescence of previously injected hematoporphyrin derivative. The system included a 200W mercury vapor lamp and primary filter, flexible fiberoptic bronchoscope with special violet-transmitting light conductor, secondary filter and image intensifier tube. Tests indicated the system could detect a tumor only 100 .mu.m thick at the expected concentration of hematoporphyrin derivative: 1 .mu.g/gm at 48-96 h following i.v. injection at a dosage of 2.5 mg/kg. Examination of resected specimens (6 of lung, 1 of esophagus) showed positive fluorescence in all cases, with fluorescence visible beyond the region visible under conventional white light examination. Fluorescence bronchoscopy has been performed on 4 patients thus far. Positive fluorescence was observed in all 3 cases where the tumor had been known to occur. Positive fluorescence was also observed in the patient with sputum positive for lung cancer but negative X-ray film findings. Additional examinations are required to demonstrate the smallest lesion that can be detected in vivo.