The radioactive isotope 119Sb has high potential for use in targeted radiotherapeutic applications for treating cancer. Because the low-energy Auger electrons emitted from the 119Sb isotope have short penetrations in biological media, selective delivery of 119Sb to tumors could kill cancerous cells while leaving proximal healthy tissue undamaged. A major technical hurtle associated with the development of 119Sb treatment methods is the preparation of adequate quantities of 119Sb to support development and deployment of the potential radiopharmaceuticals. Recently, we have overcome this challenge and established a separation method for preparing sufficient quantities of 119Sb. Production relies on isolation of 119Te (the 119Sb parent) from a natural Sb target. Critical to the success of our 119Sb production procedure was the development of sufficient understanding of the basic chemistry that governed the key Te/Sb separation steps. This presentation will describe our efforts to establish that understanding using extended X-ray absorption fine structure (EXAFS) spectroscopy. Of particular importance was the oxidation state and local coordination environment (within 6 Å) of Sb and Te in solutions used in the separation steps. EXAFS spectroscopy also provided an opportunity to characterize the coordination and oxidation state of Te when bound by functionalized resins used in the Sb/Te separations. Most importantly, this study demonstrates how developing an understanding of element speciation and coordination environments provides valuable insight for the rational design of effective isotope separation procedures.

Understanding Te and Sb separations in support of targeted Auger therapy using X-ray absorption spectroscopy

255th National Meeting (2018)

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