Determination of radiochemical yields of 186Re-labelled complexes using thin layer chromatography

The reaction conditions for synthesis of three rhenium complexes 186Re-methylendiphosphonate (MDP), 186Re-hydroxyethylidendiphosphonate (HEDP) and 186Re-citrate have been investigated. Radiochemical yield of complexation has been determined by thin layer chromatography and paper chromatography. The rhenium complexation with corresponding ligand is dependent on pH values of reaction mixture, concentration of studied ligand (MDP, HEDP and sodium citrate) and concentration of reducing agent. Stannous chloride with ascorbic acid (as antioxidant) was used for reduction of perrhenate. The labeling yield of 186Re-MDP was about 90 %, of 186Re-HEDP more than 80 % and more than 75 % for 186Re-citrate under optimum conditions. Besides, the possibility of application of porphyrins as organic ligands for complexation with rhenium isotopes is examined. (authors)