Optical contrast agents and imaging systems for detection and diagnosis of cancer.

Molecular imaging has rapidly emerged as a discipline with the potential to impact fundamental biomedical research and clinical practice. Within this field, optical imaging offers several unique capabilities, based on the ability of cells and tissues to effect quantifiable changes in the properties of visible and near-infrared light. Beyond endogenous optical properties, the development of molecularly targeted contrast agents enables disease-specific morphologic and biochemical processes to be labeled with unique optical signatures. Optical imaging systems can then provide real-time visualization of pathophysiology at spatial scales from the subcellular to whole organ levels. In this article, we review fundamental techniques and recent developments in optical molecular imaging, emphasizing laboratory and clinical systems that aim to visualize the microscopic and macroscopic hallmarks of cancer.