Routine Production of 89 Zr Using an Automated Module

Zr has emerged as a useful radioisotope for targeted molecular imaging via positron emission tomography (PET) in both animal models and humans. This isotope is particularly attractive for cancer research because its half-life (t1/2 = 3.27 days) is well-suited for in vivo targeting of macromolecules and nanoparticles to cell surface antigens expressed by cancer cells. Furthermore, Zr emits a low-energy positron (Eβ+,mean = 0.40 MeV), which is favorable for high spatial resolution in PET, with an adequate branching ratio for positron emission (BR = 23%). The demand for Zr for research purposes is increasing; however, Zr also emits significant gamma radiation (Γ15 keV = 6.6 Rcm/mCih), which makes producing large amounts of this isotope by hand unrealistic from a radiation safety standpoint. Fortunately, a straightforward method exists for production of Zr by bombarding a natural Y target in a biomedical cyclotron and then separation of Zr from the target material by column chromatography. The chemical separation in this method lends itself to remote processing using an automated module placed inside a hot cell. In this work, we have designed, built and commissioned a module that has performed the OPEN ACCESS Appl. Sci. 2013, 3 594 chemical separation of Zr safely and routinely, at activities in excess of 50 mCi, with radionuclidic purity > 99.9% and satisfactory effective specific activity (ESA).