PINGYANGMYCIN AS A TC-99M CARRIER IN TUMOR-LOCALIZATION

A simple method of preparation of Tc-99m-pingyangmycin (PYM) for clini cal use has been established using super-micro-amounts of SnCl2 as a r eductant under dark conditions. The labeling efficiency was higher tha n 96%, and further purification was not necessary. The effect of ascor bic acid on the distribution of Tc-99m-PYM had been investigated. Asco rbic acid increased uptake of Tc-99m-PYM in the tumor. Tumor uptake in creased with increasing concentration of ascorbic acid. Tumor-blood, t umor-liver, tumor-lung ratios at 1.5 h after Tc-99m-PYM administration were 5.19 +/- 1.64, 2.71 +/- 0.51 and 4.15 +/- 0.57, respectively. pr eliminary clinical trials in nine patients showed that Tc-99m-PYM is a potentially useful tracer for tumor detection with good sensitivity a nd specificity (true positive 7/7, true negative 1/1, and false positi ve 1/1).