Surface treatments of silver rods with enhanced iodide adsorption for I-125 brachytherapy seeds

• Surface treatment of silver rods with several ligands was investigated to find optimum ligand for production of I-125 seeds.
• Activity of adsorbed iodide was increased up to 499% on HNO3-etched rods compared to H2O-washed rods.
• When H2O2 was used as an oxidant for surface-modification, the amount of adsorbed iodide was increased up to 589%.
• Activity of adsorbed iodide exhibited the highest value (137.90 MBq/rod) on rods etched and treated with PO43−PO43− and H2O2.

This study described an effective method to load 125I on silver rods for the preparation of a brachytherapy source. We tested various ligands on the silver rod surface to screen the one with the highest adsorption and specific radioactivity. In addition, we investigated the effect of surface etching to increase the adsorption capability followed by the extended surface area. We also found that the use of an oxidant during iodide adsorption can increase the loading significantly. The maximum activity of 137.90 MBq/rod (3.7269 mCi/rod) was achieved on the etched silver rods with phosphate ligand and hydrogen peroxide as an oxidant. In addition, this is 4.5-fold higher than that of the conventional chloride treatment method.