Ga-67 and Fe-59 distributions in mice.

Tissue distributions of i.v.-injected Ga-67 citrate and [59Fe] ferric citrate were measured in normal mice and in lymphoid-tumor hosts. The study arose out of previously reported tissue-culture work showing marked transferrin stimulation of Ga-67 and Fe-59 uptakes by cultured cells from mouse lymphoid tumors. In vivo, however, no obvious correlation was found between Ga-67 and Fe-59 tissue distributions; indeed, Ga-67 showed high affinity for tumor tissue and low affinity for hemopoietic tissues, while for Fe-59 the reverse applied. Taken together, these comparisons of kinetics and distributions for Ga-67 and Fe-59 suggest that a tissue's avidity for Ga-67 is strongly influenced by other factors besides the cell population's capacity for transferrin interactions.