Gd2O3-based contrasting agents for photon-counting computed tomography: Effect of structure, composition, and particle size

Abstract

New contrast agents (CAs) for photon-counting computed tomography (PCCT) were synthesized, including Gd2O3@SiO2 core-shell structures and surface-modified Gd2O3–SiO2–C3H6NH2 nanoparticles. Their composition and structure were assessed by IR spectroscopy, scanning electron microscopy, X-ray phase analysis, and thermogravimetric analysis. The X-ray attenuation of synthesized particles Gd2O3@SiO2 with a size of 150–200 nm and Gd2O3–SiO2–C3H6NH2 with a size of 200–300 nm, as well as the sample of Gd2O3 with a particle size of 300–500 nm in gelatine dispersion, was investigated in phantom studies by PCCT. Energy-specific X-ray attenuation properties of all CA types correlated with their Gd concentrations. Gd2O3 demonstrated higher X-ray attenuation compared to Gd2O3@SiO2 and Gd2O3–SiO2–C3H6NH2 at the same concentrations of Gd, which can be explained by the effect of the SiO2 shells.