In accordance with at least one aspect of this disclosure, there is provided an
imaging agent, a including dye compound conjugated to an
antigen specific targeting vector which can be particularly advantageous because their behavior
in vivo can contribute to superior
optical imaging properties, for example, by significantly increasing the target-to-background ratio of imaged tissues, leading to higher resolution imaging, and ultimately providing for better recognition of malignant tissue for resection and margin assessment and improved
visualization during minimal invasive
laparoscopic surgery, for example. A method of imaging
tumor cells in a subject, can include, administering an imaging effective amount of an
imaging agent according at least one embodiment of the invention; 2-4 hours after administration of the
imaging agent, irradiating a region in the subject in which
tumor cells are expected to be found with at a
wavelength absorbed by the imaging agent; and detecting a
signal from the imaging agent, thereby imaging the
tumor cells, wherein the target-to-background ratio 2-4 hours after administration is from about 2.75 to about 15.