Abstract
The labeling of MAG3 with carrier-free 188Re from the 188W/188Re generator was investigated by the direct Snreduction (solid-phase synthesis) and the indirect labeling method using citrate or gluconate as a transfer ligand. Optimum pH range were 12.1-12.6 for the direct Sn reduction, 2-5 for the use of citrate and 2.6-3 for the use of gluconate. Although the differences of the optimum conditions such as pH and reaction time at room temperature were observed by using a different transfer ligand, the labeling yield of 188Re-MAG3 synthesized by the all methods was over 90% under the optimum conditions. The solid-phase synthesis requires the operation under a stream of nitrogen gas and the evaporation of solvent. On the other hand, the method using a transfer ligand is one-pot preparation by just heating a reaction mixture. Thus, judging from the ease of operations, the method using a transfer ligand is more convenient.
