Synthesis, tissue distribution and tumor uptake of [99Tc]tetrasulfophthalocyanine

99Tc-labeled-tetrasulfophthalocyanine was prepared by the condensing of sulfophthalic acid and pertechnetate in the presence of a reducing agent. Reaction products were purified in various chromatographic systems and characterized by combustion, specific activity and spectral analyses. The tissue distribution pattern of the major product was studied in tumor-bearing rats. Most of the activity accumulated in the liver, kidneys, ovaries and uterus, whereas tumor uptake mainly occurred in the exterior cell layers. The in vivo stability of the complex was evidenced by the absence of 99Tc accumulation in the thyroid and the stomach.