Date of Award
Doctor of Philosophy
Paul Dalhaimer, Howard Hall, George Schweitzer, Jack Watson
Interest in the use of alpha radiation emitters in radio immunotherapy is due to the high linear energy transfer and short range of alpha radiation. These properties enable the targeting of single tumor cells with diminished risk of damaging the surrounding tissue. Significant research has been done in the separation of the alpha emitter Bismuth-213 from its parent solution of Actinium-225 using organic resins. Due to radiolytic damage to the resin emphasis in the research has focused on the rapid elution of Bismuth-213 or storage of the parent Actinium-225 solution on a more robust resin. Inorganic ion exchange resins have shown a greater resistance to radiolytic damage than organic resins. If an inorganic resin could retain its structural integrity then Actinium-225 could be loaded on an inorganic resin bed with a clinical dose of Bismuth-213 eluted from the column when needed. The performance of two inorganic ion exchange resins, Isolute SCX and Isolute SCX-2, were compared to the performance of the organic resin AG-50X8 in the separation of the radionuclide Bismuth-213 from its parent solution of Actinium-225. Performance was based on the percent of Bismuth-213 available eluted, and the breakthrough of Actinium-225. It was found that Isolute SCX and Isolute SCX-2 produced less of the Bismuth-213 available on the column. The breakthrough of the Actinium-225 for all three columns was well below the toxicity level. Further tests showed that Isolute SCX and Isolute SCX-2 suffered less apparent damage from radiation generated in situ.A comparison of the ion exchange properties of the inorganic resin Isolute SCX-2 with alkali metal cations, including francium, to several better known organic resins is also presented. With hydrophobic organic ion exchange resins the selectivity of alkali metal cations tends to increase as the mass of the ion increases while the selectivity's for the less hydrophobic Isolute SCX-2 increased from francium to cesium to potassium to sodium. Lithium had the lowest selectivity, likely due to the strong hydration of the ion, and rubidium did not follow the selectivity trends of the other alkali ions.
Moore, Mark Alan, "The Separation of Bismuth-213 from Actinium-225 and the Ion Exchange Properties of the Alkali Metal Cations with an Inorganic Resin. " PhD diss., University of Tennessee, 2017.