Optimization of the production process of gadolinium oxide targets for nuclear medicine by spark plasma sintering

Terbium-155 (155Tb) radionuclide is in the recent years under the spotlight of the nuclear medicine scientific community, leading an excellent candidate for the theranostic approach due to its useful nuclear properties. However, terbium radionuclides application is extremely challenging because of their limited availability in enough amounts mainly for supply issues. Developing suitable and reliable solid targets is a technological issue in the cyclotron-based production of medical radionuclides. The present study investigates the Spark Plasma Sintering (SPS) technique to manufacture coin-shaped gadolinium oxide (Gd2O3) targets for 155Tb production by low-energy (i.e. medical) cyclotrons. A key feature of this approach is the multilayer configuration, consisting of a niobium backing (disk Ø 23.5 mm, 99.9% purity), a platinum foil (25 μm thick, 99.99+% purity), and a sintered pellet of natGd2O3 starting from powder (particle size <10 μm). Different temperatures and sintering configurations were tested to optimize the process. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) were used to analyze the powder, pellets, and targets both from morphological and microstructure features. The main outcomes emerged demonstrate the feasibility of manufacturing coin-shaped Gd2O3 targets via the SPS technique, thus underscore its potential to enable routine 155Tb production through the 155Gd(p,n)155Tb reaction route with medical cyclotrons.