Production of iodine-131 by the wet distillation of tellurium dioxide

Carrier-free I-131 suitable for medical use was produced from tellurium dioxide using the wet distillation method. Five gram samples of TeO₂ were irradiated intermittently in the beam port (BX-2) of the Philippine Research Reactor up to 250 hours (based on reactor operation of 12 hours a day, Monday to Friday). The irradiated tellurium dioxide was then dissolved in sodium hydroxide. An oxidant was added and after a predetermined amount of sulfuric acid was added, I2 131 was distilled off and subsequently reduced in a solution of sodium hydroxide. An oxidant was added and after a predetermined amount of sulfuric acid was added, I₂131 was distilled off and subsequently reduced in a solution of sodium hydroxide trickling in a vertical absorber filled with glass beads. The gamma spectrum showed peaks due only to I-131 and half-life determination followed for more than five half-lives giving an average value of 8.03 days for three runs. The absence of tellurium in the product was confirmed by the method of Gopal and Frapart having a sensitivity of ~ µg.