PRODUCTION BY COMPACT CYCLOTRON OF RADIOCHEMICALLY PURE I-123 AS IODIDE FOR SYNTHESIS OF RADIODIAGNOSTIC AGENTS

Abstract

123I-labeled radiopharmaceuticals are desirable because they give a high flux of 159-keV photons and a low radiation exposure per mCi. Procedures suited to a compact cyclotron were developed to produce 50-mCi batches of radiochemically pure 123I as iodide. 123I is separated from proton-irradiated 124T by distillation. Aqueous iodide is readily obtained by reduction with thiosulfate. Anhydrous iodide is extracted from the distillate with methyl ethyl ketone. The procedures for isolating radiochemically pure iodide are trouble-free, convenient and reliable. 123I-labeled o-iodohippurate and 16-iodo-9-hexadecenoic acid prepared from the iodide are now being used in clinical trials.