Ionic competition and 67Ga in vivo accumulation

The effect of several citrates of trivalent cations on 67Ga citrate uptake by tumor-bearing animals has been studied. A relationship between the ionic size of the simultaneously injected cation and the 67Ga uptake inhibition indicates that the cation characteristics (ionic radius and electrical charge) seem to play the most important role in this radioactivity accumulation. The apparent agreement of this phenomenon with the isomorphous replacement hypothesis is discussed.