Biodistributions of radioactive bipositive metal ions in tumor-bearing animals.

Distributions of the nuclides 65ZnCl2, 85SrCl2, 58CoCl2 and 103PdCl2 in tumor-bearing animals were determined, and, in addition, the distributions of these nuclides in tumor tissues were observed. Their subcellular distribution in tumor and liver was also examined. Generally speaking, retention values of these bipositive metal ions in tumor were smaller than those of tri-, quadri- and pentavalent metal ions. In the case of 85SrCl2, a large amount of this nuclide was taken up by the bone and remained there for a long time. In the case of 103PdCl2, 103Pd was avidly taken up by the kidney and liver. Very little of the 103Pd taken up into the kidney and liver was excreted. 65Zn and 103Pd were concentrated in the viable tumor tissue and were not seen in necrotic tumor tissue. In the case of 58Co, lysosome played an important role in liver accumulation and played a minor role in tumor accumulation. The distribution of 58Co in tumor and liver was fairly similar to that of 67Ga, 111In, 169Yb, 46Sc, 51Cr, 95Zr, 181Hf, 95Nb and 182Ta which were reported previously. Lysosome did not play an important role in the accumulation of 65Zn, 85Sr and 103Pd into tumor and liver.