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Title: Scale-up of high specific activity 186gRe production using graphite-encased thick 186W targets and demonstration of an efficient target recycling process

Production of high specific activity 186gRe is of interest for development of theranostic radiopharmaceuticals. Previous studies have shown that high specific activity 186gRe can be obtained by cyclotron irradiation of enriched 186W via the 186W(d,2n) 186gRe reaction, but most irradiations were conducted at low beam currents and for short durations. In this paper, enriched 186W metal targets were irradiated at high incident deuteron beam currents to demonstrate production rates and contaminants produced when using thick targets. Full-stopping thick targets, as determined using SRIM, were prepared by uniaxial pressing of powdered natural abundance W metal or 96.86% enriched 186W metal encased between two layers of graphite flakes for target material stabilization. An assessment of structural integrity was made on each target preparation. To assess the performance of graphite-encased thick 186W metal targets, along with the impact of encasing on the separation chemistry, targets were first irradiated using a 22 MeV deuteron beam for 10 min at 10, 20, and 27 μA, with an estimated nominal deuteron energy of 18.7 MeV on the 186W target material (after energy degradation correction from top graphite layer). Gamma-ray spectrometry was performed post EOB on all targets to assess production yields and radionuclidic byproducts. The investigationmore » also evaluated a method to recover and recycle enriched target material from a column isolation procedure. Material composition analyses of target materials, pass-through/wash solutions and recycling process isolates were conducted with SEM, FTIR, XRD, EDS and ICP-MS spectrometry. Finally, to demonstrate scaled-up production, a graphite-encased 186W target made from recycled 186W was irradiated for ~2 h with 18.7 MeV deuterons at a beam current of 27 μA to provide 0.90 GBq (24.3 mCi) of 186gRe, decay-corrected to the end of bombardment. ICP-MS analysis of the isolated 186gRe solution provided data that indicated the specific activity of 186gRe in this scaled-up production run was 2.6±0.5 GBq/μg (70±10 Ci/mg).« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [1]
  1. Univ. of Washington, Seattle, WA (United States). Dept. of Radiation Oncology
  2. Univ. of Washington, Seattle, WA (United States). Chemistry Dept.
  3. Univ. of Washington, Seattle, WA (United States). Materials Science and Engineering Dept.
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  5. Brookhaven National Lab. (BNL), Upton, NY (United States). Medical Isotope Research and Production Program; Univ. of Missouri Research Reactor Center, Columbia, MO (United States)
  6. Univ. of Missouri Research Reactor Center, Columbia, MO (United States)
  7. Univ. of Missouri, Columbia, MO (United States). Dept. of Chemistry
Publication Date:
Report Number(s):
BNL-114854-2017-JAAM
Journal ID: ISSN 0033-8230
Grant/Contract Number:
SC0012704; SC0007348
Type:
Accepted Manuscript
Journal Name:
Radiochimica Acta
Additional Journal Information:
Journal Volume: 105; Journal Issue: 12; Journal ID: ISSN 0033-8230
Publisher:
de Gruyter
Research Org:
Brookhaven National Lab. (BNL), Upton, NY (United States); Univ. of Missouri, Columbia, MO (United States); Univ. of Washington, Seattle, WA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26); Natural Sciences and Engineering Research Council of Canada (NSERC)
Country of Publication:
United States
Language:
English
Subject:
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; Re-186g; W target; graphite-encased target; deuteron induced reaction; high specific activity; enriched target recycling
OSTI Identifier:
1425126