New X-Ray Contrast Agents Based on RE-Tantalates and their Solid Solutions: An Advancement of Research

Abstract

The aim of this study was to develop new gel X-ray contrast agents (RCA), in which the substances are tantalates of rare-earth elements or solid solutions based thereon in micro and nanosized states. The next aim was to provide an increase in contrast over time, which would improve diagnostic accuracy and reduce radiation exposure to patients. Orthotantalats MTaO₄ (M = Y, La, Gd) and solid solutions La_1-xGd_xTaO₄ were considered as such substances. The RCA were examined in vitro and in vivo. When gel lanthanum orthotantalate was used as a RCA for contrast studies of the bile passages, this method exhibited a high resolving power in the examination of the hepatic tree and the gallbladder and in the diagnostics of intracavitory masses in ducts and the gallbladder. In contrast to iodine-containing urografin, this RCA has no negative effect on the mucous tunic of the bile passages of laboratory animals. Using the substitutional solid solutions, one can continuously change the specific effectiveness of RCA by gradual varying of the composition and the average size of the substance particles.