TUMOR-DETECTION AND VISUALIZATION USING CYANINE FLUOROCHROME-LABELED ANTIBODIES

Tumor localization using fluorescence has been made practical by curre nt improvements in tumor targeting molecules, especially monoclonal an tibodies and their derivatives, by the development of convenient near- infrared emitting fluorochromes and by the availability of digital cam eras having high sensitivity in this spectral region. Recent studies i n animals have demonstrated that fluorochrome labeling of monoclonal a ntibodies confers adequate sensitivity and improved resolution. Distri bution and catabolism of fluorochrome-labeled and radiolabeled antibod ies are similar. Simultaneous localization of multiple reagents is mad e possible by labeling with several different near-infrared emitting f luorochromes; thus background subtraction and differential labeling of multiple tumor-associated components can be performed. Difficulties i n using the fluorochrome labels are mainly related to light scattering and absorption in tissues, but detection of small tumors at depths of several millimeters is feasible. The major medical use of this new te chnology is likely to be endoscopic location of tumors. Scientific use s include studies of tumor metastasis, uptake and distribution of drug s and tumor-targeting molecules by tumors, and migration patterns of n ear-infrared labeled cells in vivo.