The proposal is aimed at the development of a generator for ionic gallium-68 using column chromatography (ion exchange or adsorption chromatography). The generator should be simple to manipulate, and should reproducibly deliver galliom-68 in a small volume up to 1,000 times without contamination of the product by any germanium-68 breakthrough. The chromatographic systems under consideration are based on inorganic adsorbents like silica gel, hydrous zirconium oxide and titanium dioxide and on organic supports for the ion exchange or adsorption of germanium. Stress will be laid on the yield of gallium-68 and the purity of the eluates from boh the chemical and radiochemical standpoints. Distribution coefficients between the various substrates and eluates will be determined and experimental generators of increasing activity will be build. Toxicity studies will be carried out in two animal species using the products of chemically attractive generator systems. The suitability of the generator eluate for the production of injectable gallium-68 labeled compounds will be investigated.