Fluorescence imaging of premalignant and malignant tissues with and without photosensitizers

A fluorescence imaging device exploiting differences in tissue autofluorescence between pre- malignant, malignant and normal tissues was developed to detect and clearly delineate the exact location and extent of these lesions. The device consists of a Helium-Cadmium laser (442 nm) for illumination and two image-intensifies CCD cameras with a red and green filter to capture a red and green fluorescence image simultaneously onto an imaging board of a computer. A pseudo-image is then computed and displayed in real time. In patients with known or suspected lung cancer, dysplastic lesions and carcinoma in-situ were localized that would otherwise escape detection by conventional white-light bronchoscopy. The extent of endobronchial spread of tumor can be accurately determined, which is important for successful application of photodynamic therapy for early lung cancer. The same device can also be used to study the uptake and distribution of fluorescent antineoplastic agents such as Taxol and Doxorubicin. Preliminary studies in mice bearing SCCVII squamous sell carcinoma suggest preferential retention of Taxol in tumor tissues 4 to 44 hours after intravenous injection.