A Dual PET / MR Imaging Nanoprobe : 124 I Labeled Gd 3 N @ C 80

The current report describes the development of a dual modality tomographic agent for both positron emission tomography and magnetic resonance imaging (PET/MRI). The dual-modality agent in this study was based on a I (PET) radiolabeled tri-gadolinium endohedral metallofullerene Gd3N@C80 (MRI) nanoprobe platform. The outer surface of the fullerene cage of the Gd3N@C80 metallofullerenes was surface functionalized with carboxyl and hydroxyl groups (f-Gd3N@C80) using previously developed procedures and subsequently iodinated with I to produce I-f-Gd3N@C80 nanoprobe. Orthotopic tumor-bearing rats were infused intratumorally by convection-enhanced delivery (CED) with the I-f-Gd3N@C80 agent and imaged by MRI or micro PET. The anatomical positioning and distribution of the I-f-Gd3N@C80 agent were comparable between the MRI and PET scans. The I-f-Gd3N@C80 dual-agent distribution and infusion site within the tumor was clearly evident in both T1and T2-weighted MR images. The results demonstrate the successful preparation of a dual-modality imaging agent, I-f-Gd3N@C80, which could ultimately be used for simultaneous PET/MR imaging.