Nanodiamonds – synthetic industrial diamonds only a few nanometers in size – have recently attracted considerable attention because of the potential they offer for the targeted delivery of vaccines and cancer drugs and for other uses. Thus far, options for imaging nanodiamonds have been limited. Now a team of investigators based at the Athinoula A. Martinos Center for Biomedical Imaging at Massachusetts General Hospital has devised a means of tracking nanodiamonds noninvasively with magnetic resonance imaging (MRI), opening up a host of new applications. They report their findings today in the online journal Nature Communications.