Imaging targeted-agent binding in vivo with two probes

Abstract

An approach to quantitatively image targetedagent binding rate in vivo is demonstrated with dual-probe injection of both targeted and nontargeted fluorescent dyes. Images of a binding rate constant are created that reveal lower than expected uptake of epidermal growth factor in an orthotopic xenograft pancreas tumor (2.3 × 10 -5 s -1), as compared to the normal pancreas (3.4× 10 -5 s -1). This approach allows noninvasive assessment of tumor receptor targeting in vivo to determine the expected contrast, spatial localization, and efficacy in therapeutic agent delivery. © 2010 Society of Photo-Optical Instrumentation Engineers.