Ga2O for target, solvent extraction for radiochemical separation and SnO2 for the preparation of a 68Ge/68Ga generator

The target for the production of 68Ge consists of a disc of gallium suboxide, Ga2O, with a 19 mm diameter. The suboxide was primarily prepared by repeatedly mixing metallic Ga and Ga2O3 at 700 deg C. The target (2.4 g) was quite stable under a long-time irradiation with a 34 MeV proton beam at a current of ∼80 μA. The dissolution of the target was performed using 12M sulphuric acid solution, assisted with the dropwise addition of 30% H2O2 solution, and took less than 4 hours. A solvent extraction method, using a 9M H2SO4 - 0.3M HCl/CCl4 system, was employed for the radiochemical separation of 68Ge from Ga and Zn radionuclides, while 0.05M HCl was used for the back extraction of 68Ge from the organic phase. The 68Ge obtained in the dilute HCl was directly loaded onto a column containing either a hydrous tin dioxide or a crystalline tin dioxide, obtained by calcinations of the hydrous oxide at 450, 700, and 900 deg C. The calcinated hydrous tin dioxide at 900 deg C showed the highest crystallinity and highest 68Ga elution yield and was selected for use in the generator. The 68Ga elution from the column generator packed with 2 g of tin dioxide, using 3 ml of 1M HCl, and yielded an average of 65%. The breakthrough of 68Ge was 6.1 x 10-4%. (author)