A Tumor-specific Localizing Agent for Radioisotope lmage (III)

—The Synthesis of 5-lodocytosine-¹³¹I and lts Distribution in Tumor Bearing Mice—

Abstract

5-iodocytosine-¹³¹I was synthesized by the exchange reaction of 5-IC with Na¹³¹I. Specific activity of synthesized 5-¹³¹IC was 450 μCi/mg (0. 34 mCi/ml) . The autoradiolysis was 7% in 30 days.
Studies of distribution of 5-¹³¹IC in mice and scintiphotography indicated that the intraperitoneally injected 5-131IC was incorporated into the stomach, lung and tumor, and excreted to the kidney. The whole body macroautoradiography showed the incorporation of 5-¹³¹IC into the implanted tumor in mice (6 hr after intraperitoneal injection) .