PET imaging of radiolabeled gold nanoshell structure with tumor. (a) Synthesis of radiolabeled AuNS conjugates. (b) Pharmacokinetics, expressed as the percentage of the injected dose (%ID), of 64Cu-DOTA, 64Cu-DOTA-PEG2K, and 64Cu-NS at 0, 4, 20, and 44 h p.i. Significantly different pharmacokinetics between 64Cu-NS and the two controls are evident at 4 h p.i. (p <0.05). (c) PET images at different time points with three different probes. (64Cu-DOTA, 64Cu-DOTA-PEG2K, and 64Cu-NS) (d) Biodistribution of 64Cu-NS in several major organs. (Adapted with permission from Ref. 18. Copyright (2010) Elsevier).