Physical and biological examination of gel Y₂O₃ microspheres for radioembolization therapy

Radioembolization is a specific type of internal radiotherapy used to treat primary or metastatic hepatic tumors. The basis of this therapy is the intra-arterial insertion of microspheres containing beta radioactive yttrium in the vicinity of the tumor tissue. The aim of the work was carried out physical and biological experiments performed to determine radiometric parameters and to define the possible medical usefulness of the newly developed gel ⁹⁰Y₂O₃ microspheres. Manufacturing based on the sol-gel method allowed to obtain spherical, yttrium trioxide grains of fully polycrystalline structure 20-100 μm diameter (62.1 % of the total batch). NAA analysis confirmed a high concentration of radioactive ⁹⁰Y in the sample (>99.99 %). The developed procedure for determining the specific activity of a single microsphere showed that at the time of administration, the activity can be specified at the level of 2600-3200 Bq per microsphere. The reduction in colorectal cancer cell proliferation in vitro confirms the significant influence of beta radiation from yttrium-90 trioxide microspheres. Histopathological examination of the distribution of microspheres in the animal model confirmed the proper location of yttrium trioxide microspheres inside blood vessels in a porcine model. Gel Y₂O₃ microspheres manufactured using the sol-gel method showed relevant properties, indicating the possible use of microspheres for further biological and preclinical studies.