Is indocyanine green (ICG) used for small animal in vivo imaging?

Yes, indocyanine green (ICG) is used for small animal in vivo imaging. It has been successfully used in vivo imaging in rats and dogs.

ICG is a negatively charged, tricarbocyanine dye that is widely exploited for its low toxicity and infrared fluorescence emission. ICG’s minimal toxicity is attributed to its strict binding with plasma proteins. This confines it to the vascular compartment where it is rapidly metabolized by the liver and excreted exclusively by the liver and bile ducts. ICG and ICG derivatives can be used as in vivo molecular imaging probes. Their infrared fluorescence emission penetrates tissues several millimeters to facilitate deep tissue and small animal in vivo imaging.