Technical note
Recovery of 131I from alkaline solution of n-irradiated tellurium target using a tiny Dowex-1 column

https://doi.org/10.1016/j.apradiso.2010.04.033Get rights and content

Abstract

A simple and inexpensive ion-exchange chromatography method for the separation of medically useful no-carrier-added (nca) iodine radionuclides from bulk amounts of irradiated tellurium dioxide (TeO2) target was developed and tested using 131I. The radiochemical separation was performed using a very small Dowex-1×8 ion-exchange column. The overall radiochemical yield for the complete separation of 131I was 92±1.8 (standard deviation) % (n=8). The separated nca 131I was of high, ∼99%, radionuclidic and radiochemical purity and did not contain detectable amounts of the target material. This method may be adopted for the radiochemical separation of other different iodine radionuclides produced from tellurium matrices through cyclotron as well as reactor irradiation.

Introduction

Iodine has several important radioisotopes viz. 131I, 123I, 124I with nuclear and biochemical properties suitable for several biomedical and nuclear medicine applications.

The most common production methods of 131I, 123I, 124I nuclides are based on irradiation of tellurium metal/tellurium dioxide with thermal neutrons in a reactor e.g. 131I produced by the reaction 130Te(n, γ) 131Teβ131I, or with light charged particles in cyclotrons through various reaction routes such as 123Te (p, n)123I or 124Te (p, 2n)123I, 124Te (p, n)124I, etc. (Qaim, 2003, Clem and Lambrecht, 1991, Qaim and Stöcklin, 1983, Acerbi et al., 1975).

Several radiochemical separation techniques such as dry distillation, solvent extraction, ion-exchange separation, charcoal column chromatography, etc. (Chattopadhyay and Saha Das, 2009, El-Azony and Qaim, 2008, Qaim, 2003, Salacz, 1989, Case and Acree, 1966) have been reported for the isolation of iodine radionuclides from Te or TeO2 targets. Tellurium (Te), either as metallic Te or as tellurium dioxide (TeO2), is used as target material for irradiation. The aim of the present work was to develop a simple, versatile and rapid radiochemical separation technique that would provide no-carrier-added (nca) radioiodine of high radioactive concentration (RAC), with high yield and the requisite radiochemical purity, from cyclotron as well as reactor-irradiated TeO2 targets.

Section snippets

Materials

All chemicals were from commercial sources and were mostly of AR/GR grade. Natural tellurium (IV) oxide, TeO2, Puratonic, 99.9995% (metal basis) purchased from Alfa Aesar, MA, USA, was used for irradiation in the nuclear reactor and for the chemical separation. Iodine-131 was obtained from the Radiochemicals Section, Radiopharmaceutical Division, BARC, Trombay. Dowex-1×8 (Cl form, 200–400 mesh, capacity 3.5 meq/g of dry resin) was procured from Sigma Chemical Company.

Radionuclide analysis

All γ-ray spectroscopic

Results and discussion

In the present work the radiochemical separation of 131I from TeO2 was carried out using reactor-irradiated natTeO2 target material; however, in practice, production of nca iodine radionuclides, viz. 131I, 123I, 124I, may be produced from isotopically enriched tellurium targets by cyclotron- or reactor irradiation using charged particle and neutron induced nuclear reactions, (Qaim, 2003, Sheh et al., 2000). This requires a separation technique that would provide good yields of iodine

Conclusion

An efficient and cost effective radiochemical technique was developed to separate 131I from reactor-irradiated TeO2 targets in good yield and high quality. The simple technique developed may be used for the large scale production of other iodine radioisotopes with high yield from reactor- or cyclotron-irradiated tellurium oxide targets.

Acknowledgements

The authors gratefully acknowledge Dr. R.K. Bhandari, Director, Variable Energy Cyclotron Centre (VECC), Kolkata, India, Dr. A.K. Kohli, Chief Executive, Board of Radiation and Isotope Technology (BRIT), and Dr. M.K. Das, Head, Regional Centre, Board of Radiation and Isotope Technology (BRIT), Kolkata, for their support.

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