Rare-earth metal oxide nanoparticles considered promising contrast agents for x-ray computed
tomography (CT) and magnetic resonance imaging (MRI). The main purpose of this study is to
investigate the potential applicability of polyethyleneimine (PEI)-coated Eu2O3 and Dy2O3
nanoparticles(NPs) for CT x-ray attenuation. Morphology and other physicochemical properties of
prepared samples were systematically investigated using a range of characterization tools. Preliminary
cytotoxicity experiments with L-929 fibroblastic cells suggested that both samples have no significant
toxicity at concentrations below 100 μg ml−1
. Clinical CT analysis shows that PEI@Eu2O3 NPs exhibit
higher x-ray attenuation efficiency (∼8 HU mM−1
) as compared to PEI@Dy2O3 NPs(∼5 HU mM−1
).