Application of Co‐Crystallisation Technique for the production of carrier free SILVER‐111 from pile irradiated palladium

Abstract

Carrier free 111Ag has been separated from neutron irradiated palladium targets by the combined co‐crystallisation and electrodeposition techniques. Co‐crystallisation coefficient measurements of silver activity on NaCl were performed, and the best condition for the separation of Ag‐111 in more than 90% yield was carried out. The method requires no consumption of special chemicals and renders the quantitative separation and subsequent use of irradiated palladium possible. The purification of target before irradiation by solvent extraction eliminates radiochemical impurities expected from trace metals in the original target, particularly gold and silver. The product separated proved to be of high chemical and radiochemical purity.

Lights and Shadows on the Sourcing of Silver Radioisotopes for Targeted Imaging and Therapy of Cancer: Production Routes and Separation Methods

“…Micheev et al demonstrated that 111 Ag can be separated from neutron-irradiated palladium targets by combined co-crystallization with NaCl and electrodeposition [ 34 ]. In fact, as NaCl and AgCl are isomorphous compounds, 111 Ag + can replace a Na + ion in the crystal lattice of NaCl crystals, thus being quantitatively separated from the Pd 2+ that remains in the solution.…”

“…In the described method, the irradiated Pd target (1 mg) was treated with aqua regia (5 mL) and the obtained solution was evaporated to dryness. HCl was added and subsequently removed by evaporation [ 34 ]. The residue was dissolved in a saturated NaCl solution (50 mL) at 50 °C and the mixture was filtered with a G3 sintered glass disk.…”

“…In the right conditions, it was shown that traces of co-precipitated Pd 2+ do not exceed 0.01% of the separated 111 Ag + activity. Finally, the authors stated that the saline solution containing 111 Ag + can be directly used for medical preparations or, alternatively, it can be readily separated by electrodeposition on a Pt electrode and subsequently dissolved in HNO 3 [ 34 ].…”

“…Micheev et al demonstrated that 111 Ag can be separated from neutron-irradiated palladium targets by combined co-crystallization with NaCl and electrodeposition [34].…”

Chromatographic separation of silver-111 from neutron-irradiated palladium target: toward direct labeling of radiotracers

“…Several methods for the extraction of silver-111 from neutron-irradiated palladium targets have been explored. These methods include ion exchange chromatography (Aweda et al 2013 ; Bauer et al 1997 ; Lyle and Maghzian 1968 ; Mansur et al 1995 ; Ohya et al 2020 ; Ooe et al 2019 ; Taylor 1961 ; Vimalnath et al 2007 ), alumina adsorption (Khalid et al 2000 ), liquid/liquid extraction (Alberto et al 1992 ; Lahiri et al 1997a , b ), precipitation (Blackadar et al 2022 ; Collins et al 2014 ; Haymond et al 1950 ; Sicilio et al 1956 ; Zimen 1949 ), co-crystallization (Micheev et al 1964 ) and electrodeposition (Griess and Rogers 1952 ). Nonetheless, many of these procedures involve the co-addition of macroscopic quantity of stable silver carrier or other chemical species (e.g.…”