Routine Production of 89Zr Using an Automated Module

Zr-89 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 (t(1/2) = 3.27 days) is well-suited for in vivo targeting of macromolecules and nanoparticles to cell surface antigens expressed by cancer cells. Furthermore, Zr-89 emits a low-energy positron (E-beta+,E-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-89 for research purposes is increasing; however, Zr-89 also emits significant gamma radiation (Gamma(15) (keV) = 6.6 R.cm(2)/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-89 by bombarding a natural Y target in a biomedical cyclotron and then separation of Zr-89 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 chemical separation of Zr-89 safely and routinely, at activities in excess of 50 mCi, with radionuclidic purity > 99.9% and satisfactory effective specific activity (ESA).