Separation of Radiocopper 64/67Cu from the Matrix of Neutron-Irradiated Natural Zinc Applicable for 64Cu Production

Abstract

Radioisotope ⁶⁴Cu is a promising radiometallic-isotope for molecular-targeted-radiopharmaceuticals. Having a half-life of 12.70 hours and emitting β⁺-radiation (E_β+ = 0.6531 MeV) as well as β^-ray (E_β- = 0.5787 MeV), it is widely used in the form of biomedical-substrate-radiopharmaceutical for positron emission tomography (PET) diagnosis and simultaneously for targeted radiotherapy of cancer. The potential needs on the availability of ⁶⁴Cu-labeled pharmaceuticals for domestic nuclear medicine hospitals lead to a necessity for the local production of carrier-free ⁶⁴Cu using BATAN’s G.A. Siwabessy reactor because of the technical and economical constraints in the production using BATAN’s cyclotron. The presented work is accordingly to study whether the radioisotope ⁶⁴Cu can be produced and separated from the matrix of post-neutron-irradiated-natural zinc. This study is expected can be further improved and implemented in production technology of carrier-free ⁶⁴Cu based on ⁶⁴Zn (n,p) ⁶⁴Cu nuclear reaction exploiting the fast neutron fraction among the major thermal fraction due to unavailability of fast-neutron-irradiation facility in the BATAN’s G.A. Siwabessy reactor. The solution of post-neutron-irradiated-natural zinc in 1M acetic acid was loaded into Chelex-100 cation exchanger resin column to pass out the Zn/Zn* fraction whereas the Cu* fraction which remained in the column was then eluted out from the column by using 1.5 M HCl and loaded into the second column containing Dowex-1X8 anion exchanger resin. The second column was then eluted with 0.5 M HCl. The collected eluate was expected to be zinc-free Cu* fraction. It was observed from the half-life and the γ-spectrometric analysis that radioactive copper-⁶⁴Cu containing ⁶⁷Cu was produced by neutron activation on the natural Zn-foil target and can be separated from the target matrix by the presented two-steps-column-chromatographic separation technique. The radioactivity measurement showed that wrapping the Zn target with cadmium foil increased the activity of radioactive copper and, thus, the Cu*/Zn*-ratio.

Received: 28 June 2011; Revised: 21 February 2012; Accepted: 24 February 2012