Reactor production and purification of osmium-191 for use in a new 191Os/191mIr radionuclide generator system
✍ Scribed by C. Brihaye; S. Dewez; M. Guillaume; A.P. Callahan; D.E. Rice; F.F. Knapp Jr
- Publisher
- Elsevier Science
- Year
- 1989
- Weight
- 769 KB
- Volume
- 40
- Category
- Article
- ISSN
- 0883-2889
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✦ Synopsis
The production of osmium-191 by thermal neutron irradiation of enriched osmium-190 has been evaluated at neutron flux values from 4 x lOI to 2.5 x lOI neutron cmV2 s-' in the Oak Ridge High Flux Isotope Reactor (HFIR), the High Flux Brookhaven Reactor (HFBR), and the BR2 reactor in Mol, Belgium. The production route has been analyzed and the cross section values evaluated. The existence of a secondary reaction 19'Os(n, Y)'~~OS with a cross section value of 740 barn has been demonstrated. In order to obtain 'g'Os with a specific activity of 250 mCi/mg lWOs, irradiation periods at neutron flux values lower than 2.5 x lOI neutroncm-* SK' have to be extended up to 24 weeks. This results in significantly increased levels of the undesirable '%. The '921r is produced by capture of a neutron by 19'Ir, which is formed by decay of the short-lived 4.96 s 191mIr daughter produced by p-decay of "'OS. Elution of even small levels of '?r from the '910s/191mIr generator results in a large proportion of the total absorbed radiation dose from the generator eluate. Purification of 19'Os by conversion to osmium tetroxide and isolation by both distillation and solvent extraction methods has been developed for the efficient removal of 1911r.