Yttrium-90 (90Y)-polymer composite (RadioGel®) is a new cancer therapeutic agent for treating solid tumors by direct interstitial injection. The 90Y-composite comprises insoluble, microscopic yttrium-phosphate particles carried by a sterile, injectable water-polymer (hydrogel) solution that can be placed directly by needle injection into solid tumors. The yttrium-90-RadioGel® agent was designed to provide a safe, effective, localized, high-dose beta radiation for treating solid tumors. The properties of 90Y-RadioGel® also make it a relatively safe agent for health care personnel who prepare, handle, and administer the material. The purpose of this work was to demonstrate and characterize radiation safety of the injectable 90Y-RadioGel® therapeutic agent.

Purpose: Yttrium-90 (90Y)-polymer composite (RadioGel®) may be administered directly into cancerous tissues to deliver highly localized beta radiation for therapy. In a dose-escalation study, the authors investigated the feasibility of treating feline and canine soft-tissue sarcomas as a model for non resectable solid tumors in humans to gain clinical experience and to identify optimal methods for placing the composite uniformly within target tumor tissue.