Production of 125I from Neutron Irradiation of Natural Xe Gas and a Wet Distillation Process for Radiopharmaceutical Applications

In this article, we describe a simple and facile approach for the production of 125I from the neutron-irradiated natural Xe using wet chemical distillation. First, we outline the design of the irradiation container, its fabrication, cryogenic loading of the gaseous Xe target into the irradiation container, and hermetic sealing of the irradiation container. Quality-assurance tests of the irradiation containers were performed to ensure their safety during neutron irradiation. In light of the implicit need to obtain 125I activity with minimum126I radionuclidic contamination, the irradiation time, neutron flux, and target cooling time were judiciously optimized. A thorough optimization of experimental parameters of distillation was carried out to obtain the optimal yield of 125I having the desired purity. In each batch, typically 4 g of natural xenon gas was irradiated in the BARC Dhruva reactor for 15 days with a thermal neutron flux of approximately 5 × 1013 cm–2 s–1. After irradiation, the targets were lef...