Several published studies have tested the concept of a receptor-binding molecule, conjugated to a near-infrared fluorescent probe that is able to be localized in the margin of tumor and normal tissue. The goal of this and similar research is to increase the tumor-to-background contrast ratio as a means of improving the tumor delineation during surgical resection, and to determine if injection at the microdose level was a reasonable administration concentration to achieve this. In 2011, van Dam and colleagues studied the use of folate conjugated to fluorescein isothiocyanate (FITC) to target the folate receptor α (FR-α) overexpressed in ovarian cancer. This receptor-targeting fluorescent probe demonstrated a promising approach for detection of the receptor positive human tumors compared to the conventional visual inspection during standard surgery . In neurosurgery, substantial efforts have been made with the metabolic marker protoporphyrin IX produced by mitochondrial heme synthesis [31–34], and indocyanine green perfusion imaging [35–37] to delineate the tumor borders during brain surgery. Based on this basic research, dedicated surgical microscope systems are now commercially available for fluorescence image acquisition in either the red (600–750 nm) or near-infrared (800+ nm) wavelength bands .