Fluorescence Bronchoscope for Lung Tumor Localization

A fluorescence bronchoscope has been developed for localization of small bronchogenic tumors at the carcinoma in situ stage. Injected hematoporphyrin-derivative is preferentially taken up or retained by a malignant tumor, and very small amounts can be detected by the red fluorescence under excitation by violet light. The target lesion is 80 ¿m thick, with a mass of 250 ¿g, containing 250 pg of hematoporphyrin-derivative. A fiberoptic bronchoscope system with a 200W high pressure mercury arc lamp, primary filter passing 405 nm light, special violet transmitting light conductor, coherent imaging bundle, red secondary filter, and three-stage electrostatic focus image intensifier tube was designed for this application. Tumors have been visualized in animals and preparations for clinical use are underway.