68Ga-Labelled Carbon Nanoparticles for Ventilation PET/CT Imaging: Physical Properties Study and Comparison with Technegas

Purpose The use of 68 Ga-labelled carbon nanoparticles has been proposed for lung ventilation PET/CT imaging. However, no study has assessed the physical properties of 68 Ga-labelled carbon nanoparticles. The aim of this study therefore was to evaluate the shape and size of 68 Ga-labelled carbon nanoparticles, and to determine the composition of the aerosol, as opposed to 99m Tc-labelled carbon nanoparticles aerosol. Procedures 99m Tc- and 68 Ga-labelled carbon nanoparticles, stable gallium carbon nanoparticles, 0.9 % NaCl and 0.1 N HCl-based carbon nanoparticles were produced using an unmodified Technegas® generator, following the usual technique used for clinical Technegas® production. The shape and size of particles were studied by transmission electron microscopy (TEM) after decay of the radioactive samples. The composition of the 68 Zn- and 99 Tc-labelled carbon nanoparticles aerosols was assessed using scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX) analysis after decay of the 68 Ga- and 99m Tc-labelled carbon nanoparticles, respectively. Results On TEM, all samples showed similar shape with hexagonally structured primary particles, agglomerated in clusters. The mean diameters of primary stable gallium carbon nanoparticles, 99 Tc- and 68 Zn-labelled carbon nanoparticles were 22.4 ± 10 nm, 20.9 ± 7.2 nm and 19.8 ± 11.7 nm, respectively. Conclusion Using Technegas® generator in the usual clinical way, 99m Tc- and 68 Ga-labelled carbon nanoparticles demonstrated similar shape and diameters in the same size range size. These results support the use of 68 Ga-labelled carbon nanoparticles for the assessment of regional lung ventilation function with PET imaging.