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Accessible Unlicensed Requires Authentication Published by Oldenbourg Wissenschaftsverlag March 19, 2013

Proton irradiation parameters and chemical separation procedure for the bulk production of high-specific-activity 186gRe using WO3 targets

M. E. Fassbender, B. Ballard, E.R. Birnbaum, J.W. Engle, K.D. John, J.R. Maassen, F. M. Nortier, J.W. Lenz, C. S. Cutler, A.R. Ketring, Silvia S. Jurisson and D.S. Wilbur
From the journal Radiochimica Acta

Abstract

Rhenium-186g (T1/2= 89.2 h) is a β emitter suitable for therapeutic applications. Current production methods rely on reactor production via185Re(n,γ) which results in low specific activities, thereby limiting its use. Production by p,d activation of enriched 186W results in a 186gRe product with a higher specific activity, allowing it to be used for targeted therapy with limited receptors. A test target consisting of pressed, sintered natWO3 was proton irradiated at Los Alamos (LANL-IPF) to evaluate product yield and impurities, irradiation parameters and wet chemical Re recovery for proof-of-concept for bulk production of 186gRe. We demonstrated isolation of 186gRe in 97% yield from irradiated natWO3 targets within 12 h of end of bombardment (EOB) via an alkaline dissolution followed by anion exchange. The recovery process has potential for automation, and WO3 can be easily recycled for recurrent irradiations. A 186gRe batch yield of 42.7 ± 2.2 μCi/μAh or 439 ± 23 MBq/C was obtained after 24 h in an 18.5 μA proton beam. The target entrance energy was determined to be 15.6 MeV. The specific activity of 186gRe at EOB was measured to be 1.9 kCi (70.3 TBq) mmol−1, which agrees well with the result of a previous 185,186mRe co-production EMPIRE and TALYS modeling study assuming similar conditions. Utilizing enriched 186WO3, we anticipate that a proton beam of 250 μA for 24 h will provide batch yields of 256 mCi (9.5 GBq) of 186gRe at EOB with specific activities even higher than 1.9 kCi (70.3 TBq) mmol−1, suitable for therapy applications.


* Correspondence address: Los Alamos National Laboratory, Chemistry Division, Los Alamos NM 87545, U.S.A.,

Published Online: 2013-03-19
Published in Print: 2013-05

© by Oldenbourg Wissenschaftsverlag, München, Germany