Document Type : Research Paper
Authors
1 Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran, Iran
2 radiation application research school, NSTRI
3 Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran, Iran
Abstract
Ni-Cu (70.4-29.6; wt%) ferromagnetic alloy coated with an absorber layer of iodine-125, was made as a core in the Thermo-Brachytherapy (TB) system. The 100 μm thick absorber layer, featuring a microcrystalline graphite structure, comprises silver-doped activated carbon and polystyrene in a 70:30 weight ratio. Activated carbon is one of the preferred adsorbents for iodine capture due to its porous nature.
Silver doping in carbon enhances iodine-125 trapping through chemical adsorption. Polystyrene, while acting as a binder in the absorptive layer's structure, facilitates the physical absorption of iodine on the surface of the silver-doped activated carbon-coated core. The obtained results indicated that the extraction efficiency of iodine-125 (as the sodium iodide solution) with 5 mCi average activity on the nickel-copper core/polystyrene/silver-doped activated carbon was 20.31% after 2h. while gold or silver coating on the nickel-copper ferromagnetic core before depositing silver-doped activated carbon increased the extraction efficiency to 32.77% and 60.23% after 2 h, respectively. The findings display the significant impact of silver or gold coating on the enhanced extraction efficiency. More importantly, a multi-step extraction process, in which the extraction steps were repeated to increase the recovery of iodine-125, was used in this research.
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