New X-ray Contrast Agents Based on Tantalates, Silicates, Germanates of REE and Gd2O3

Tests of bulk- and nanosized radiopaque contrast agents based on solid solutions of La1-xGdxTaO4, Sr2R8 (1-x-y) ErxYbyM6O26, (R=Y, La, M=Si, Ge), and Gd2O3 are presented. The bulk substances were synthesized from the corresponding oxides in the solid phase. Nanoparticles were produced in vacuum by the pulse electron beam evaporation method. The obtained nano-samples have K-jumps of X-ray radiation absorption in the 10-100 keV region of energies. This opens up prospects for the use of nanoparticles as X-ray contrast agents (radiopaque agents). The gel suspensions based on the bulk solid solutions La1-xGdxTaO4 (x = 0 – 0.18) allow for continuous and smooth alteration of radiopaque contrast agents, thus expanding the fields of their application. Gel substances based on LaTaO4 and Gd2O3 NPs have a higher contrast than bulk substance.