Earlier studies have also investigated a cathepsin B (CatB)-activated analogue in a murine atherosclerosis model.24,25 Indeed this probe, ProSense750/VM110, was used in the first demonstration of real-time intravascular Near-Infrared Fluorescence (NIRF) catheter-based imaging, by Jaffer and co-workers in 2008.66 Ultimately, two forms of commercially-available cathepsin-activated NIRF probes have been developed, based on the scaffold outlined above; ProSense 750/VM110, activated by cathepsins B, L and S, and ProSense680, activated by cathepsins B, L, S, K, V and D.67 Here, CTSB is linked to atherosclerosis.