Separation of ⁶⁸Ga from ⁶⁸Ge using a macroporous organic polymer containing N-methylglucamin groups.

ABSTRACT
Gallium-68 (⁶⁸Ga) is a important positron-emitting radionuclide available for positron emission tomography. Since the ⁶⁸Ga is prepared by decay of germanium-68 (⁶⁸Ge) having a long half-life, separation of ⁶⁸Ga from ⁶⁸Ge is essential for the utilization of ⁶⁸Ga. In this study, a macroporous styrene-divinylbenzene copolymer containing N-methylglucamine groups (R-MGlu) was selected as an adsorbent for ⁶⁸Ge. This resin effectively and rapidly adsorbed ⁶⁸Ge above pH 5. By a batch method, 0.1 mol l^-1 trisodium citrate eluted over 90% of ⁶⁸Ga built up in the resin by decay of ⁶⁸Ge on the resin, although distilled water did not elute the ⁶⁸Ga. A solution of ethylenediaminetetraacetic acid or desferroxamine at a lower concentration also desorbed the ⁶⁸Ga in higher yield. These results indicated that ⁶⁸Ga was eluted by the formation of a complex with a suitable ligand. When 0.1 mol l^-1 sodium citrate was used as the eluting agent by a column method, most of the ⁶⁸Ga on the R-MGlu was recovered using 0.1 mol l^-1 sodium citrate, while the ⁶⁸Ge leakage was less than 0.0004% of the ⁶⁸Ge adsorbed on R-MGlu.