In vivo labeling of red blood cells with Tc-99m with stannous pyridoxylideneaminates.

Several stannous pyridoxylideneaminates were evaluated as stannous ion sources for the in vivo labeling of red blood cells (RBCs) with Tc-99m. In spite of a considerable variety of stannous preparations, rapid and efficient RBC labeling was obtained with each stannous chelate. These results suggest that the role of the ligands is merely to stabilize the divalent state of the tin. The optimal time interval between Sn(II) and 99mTcO4- injections, and the best stannous-ion concentration, was found using stannous pyridoxylideneisoleucine (Sn-P.isoL). Maximal in vivo labeling of the RBCs was obtained with an i.v. dose of 10-20 micrograms Sn(II)/kg of Sn-P.isoL followed 15-30 min later by i.v. administration of pertechnetate.