Pancreatic islet transplantation may provide an effective therapy for patients with type I diabetes. By encapsulating islets in alginate capsules, their survival is substantially improved. Methods to monitor the distribution of the encapsulated islets during delivery and afterward would help to optimize this type of therapy. Barnett and coworkers (1) showed, for the first time, it is possible to visualize encapsulated islets by using magnetic resonance (MR) imaging, computed tomography (CT), and ultrasonography (US) after the inclusion of perfluorocarbon in the capsules. Importantly, it was shown that the therapeutic effect of the islets was sustained for more than 50 days when implanted into mice.