Tissue distributions of 97Ru and 103Ru in subcutaneous tumor of rodents

Mice bearing Ehrlich tumor were administered 97Ru-chloride or 103Ru-chloride intravenously. Examinations of various tissues indicated similar distributions by the two radionuclides. The levels were higher in the lung, liver and kidney than in the tumor tissue. Rats bearing AH-130 tumor were administered 103Ru-chloride intravenously. The 103Ru distribution in rats was highest in the spleen, followed by the liver and kidney; however, the radioactive distribution in the tumor tissue exceeded the muscle level by about 5-fold. Tumors were delineated in rats by scintigraphy. The findings indicate that ruthenium radionuclides may be a useful clinical agent in the delineation of some types of tumors. Ruthenium-97 would be favored in possible clinical usage due to its shorter physical half-life and lower levels of gamma energy.