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Highlights: • Focus is on the separation of Sr from Rb, Se and other metallic impurities such as Fe, Cr, and Ni cladding materials. • SNT and CST considered as an alternative to Chelex-100 for purification of 82Sr from bulk RbCl. • CST is suitable as a material in a cleanup column for removal of Se and Rb with capacity for Rb = 0.88 meq/g. • Uptake of Sr and Rb by SNT and Chelex-100 follows pseudo-second order kinetics. The 82Sr/82Rb generator system has found use in positron emission tomography (PET) imaging of myocardial perfusion. 82Sr is produced by proton irradiation of Rb metal/RbCl salt followed by chemical separation. Inorganic ion-exchangers were synthesized by hydrothermal methods and evaluated for the purification of accelerator-produced 82Sr from a RbCl target and co-produced impurities like 75Se, Fe, Cr, and Ni. A process consisting of removal of bulk RbCl using sodium nonatitanate (SNT), then removal of remaining tracers of Rb and Se using poorly crystalline silicotitanate (pCST) is suitable for 82Sr separation and achieves higher purity of 82Sr vs. commonly used organic resins. [ABSTRACT FROM AUTHOR]

Proton irradiation of a thorium (Th) target can produce Actinium-225 (Ac-225), but the irradiated thorium fissions results in the production of 100’s of other isotopes. SynPhase Lanterns containing sulfonic acid groups were evaluated for the purification of Ac-225 from Th and other fission metals. The SynPhase Lanterns were able to quantitatively and selectively capture Ac-225 and lanthanum (La) over Th. A second purification step would be needed to purify Ac-225 from trace amounts of Th and other fission products. The results from these studies were compared to similar studies performed with cation exchange resins, and the resins were superior at removing impurities. [ABSTRACT FROM AUTHOR]

The penta ethyl ester of diethylenetriamine pentaacetic acid (DTPA) can be used as a prodrug for decorporation of radionuclides in the event of an internal radiation incidents with transuranic elements. A C18 chromatography purification method was successfully developed using a step elution profile to isolate 0.5-3 g of the four ethyl esters of DTPA. Less than 11 % of the isolated di-ethyl and tri-ethyl esters of DTPA, and less than 20 % of the tetra-ethyl ester of DTPA, had degraded in phosphate buffered saline over a 168 h period. [ABSTRACT FROM AUTHOR]

The polymer polyethyleneimine with primary and secondary chelators can retain Ac and its daughters. In this study we optimize a prelabeling approach, followed by addition of secondary chelators and explore crosslinking approaches to add a targeting molecule. A (N-Succinimidyl 3-(2-pyridyldithio)-propionate crosslinking approach was used to obtain a ~1 to 1 ratio of the modified PEI to Trastuzumab. This approach coupled with the prelabeling approach would allow the synthesis of the radiolabeled targeted polymer for Ac radioimmunotherapy. [ABSTRACT FROM AUTHOR]

Actinium-225 (225Ac) can be produced from a Thorium-229/Radium-225 (229Th/225Ra) generator, from high/low energy proton irradiated natural Thorium or Radium-226 target. Titanium based ion exchanger were evaluated for purification of 225Ac. Poorly crystalline silicotitanate (PCST) ion exchanger had high selectivity for Ba, Ag and Th. 225Ac was received with trace amounts of 227Ac, 227Th and 223Ra, and the solution was used to evaluate the retention of the isotopes on PCST ion exchanger. Over 90% of the 225Ac was recovered from PCST, and the radiopurity was >99% (calculated based on 225Ac, 227Th, and 223Ra). The capacity of the PCST inorganic ion exchange for Barium and 232Th was determined to be 24.19 mg/mL for Barium and 5.05 mg/mL for Thorium. PCST ion exchanger could separate 225Ac from isotopes of Ra and Th, and the process represents an interesting one step separation that could be used in an 225Ac generator from 225Ra and/or 229Th. Capacity studies indicated PCST could be used to separate 225Ac produced on small 226Ra targets (0.3–1 g), but PCST did not have a high enough capacity for production scale Th targets (50–100 g). [ABSTRACT FROM AUTHOR]