Magnetic resonance imaging (MRI), Computed tomography (CT) and single photon emission computed tomography (SPECT) are the most widely used modalities for disease diagnosis. Nanoparticles have emerged as a promising class of contrast-agents for in vivo imaging. We present a novel design, of iron oxide-gold nanoparticle (IONP), radioisotope labeled, for trimodal MRI/CT/SPECT imaging.
Gold solution were prepared to form the gold shell for the IONPs (Fe3O4@Au). To enable radiolabeling and cell-tracking, the particles were coated by glucose and tetracarboxylic acid (DOTA). To evaluate feasibility as an MRI contrast-agents, solutions with different concentrations were scanned on a clinical 3T MRI scanner. Quantitative measurements were carried out using standard protocols to determine MR relaxation values in free-state. The feasibility of Fe3O4@Au nanoparticles as CT contrast-agents was assessed by a micro-CT scanner. Preliminary experiments on radiolabeling of the DOTA-glucose-coated Fe3O4@Au nanoparticles were carried out.
Uniformly distributed, spherical nanoparticles, composed of 8±2 nm iron-oxide core and 19nm thick gold shell were produced. MRI relaxation values decreased with increasing nanoparticle concentration, yielding clinically relevant values for three different common MRI contrasts. Greyscale quantification demonstrated a linear correlation between CT-contrast and the nanoparticles concentration. The radiochemical yield was higher than 98%, providing a single radioactive species with limited stability of up to 24h.
The new particle design showed efficient capabilities as CT/MRI imaging agent and high radiochemical yield, indicating a potential, hybrid material for multimodal SPECT/CT/MRI imaging.