Browsing by Author "Shultz, Michael D."

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    A Dual PET/MR Imaging Nanoprobe: 124I Labeled Gd3N@C80
    Luo, Jianqiao; Wilson, John D.; Zhang, Jianyuan; Hirsch, Jerry I.; Dorn, Harry C.; Fatouros, Panos P.; Shultz, Michael D. (MDPI, 2012-05-10)
    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 124I (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 124I to produce 124I-f-Gd3N@C80 nanoprobe. Orthotopic tumor-bearing rats were infused intratumorally by convection-enhanced delivery (CED) with the 124I-f-Gd3N@C80 agent and imaged by MRI or micro PET. The anatomical positioning and distribution of the 124I-f-Gd3N@C80 agent were comparable between the MRI and PET scans. The 124I-f-Gd3N@C80_ dual-agent distribution and infusion site within the tumor was clearly evident in both T1- and T2-weighted MR images. The results demonstrate the successful preparation of a dual-modality imaging agent, 124I-f-Gd3N@C80, which could ultimately be used for simultaneous PET/MR imaging.
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    Spin transition in Gd3N@C-80, detected by low-temperature on-chip SQUID technique
    Chen, L.; Carpenter, Everett E.; Hellberg, Carl S.; Dorn, Harry C.; Shultz, Michael D.; Wernsdorfer, Wolfgang; Chiorescu, Irinel (American Institute of Physics, 2011-04-01)
    We present a magnetic study of the Gd3N@C-80 molecule, consisting of a Gd-trimer via a nitrogen atom, encapsulated in a C-80 cage. This molecular system can be an efficient contrast agent for magnetic resonance imaging (MRI) applications. We used a low-temperature technique able to detect small magnetic signals by placing the sample in the vicinity of an on-chip SQUID. The technique implemented at the National High Magnetic Field Laboratory has the particularity of being able to operate in high magnetic fields of up to 7 T. The Gd3N@C80 shows a paramagnetic behavior and we find a spin transition of the Gd3N structure at 1.2 K. We perform quantum mechanical simulations, which indicate that one of the Gd ions changes from a S-8(7/2) state (L-0, S-7/2) to a F-7(6) state (L-S-3, J-6), likely due to a charge transfer between the C-80 cage and the ion. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3536514]