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Title: Application of ion exchange and extraction chromatography to the separation of actinium from proton-irradiated thorium metal for analytical purposes

Abstract

We present that actinium-225 (t 1/2 = 9.92 d) is an α-emitting radionuclide with nuclear properties well-suited for use in targeted alpha therapy (TAT), a powerful treatment method for malignant tumors. Actinium-225 can also be utilized as a generator for 213Bi (t 1/2 45.6 min), which is another valuable candidate for TAT. Actinium-225 can be produced via proton irradiation of thorium metal; however, long-lived 227Ac (t 1/2 = 21.8 a, 99% β -, 1% α) is co-produced during this process and will impact the quality of the final product. Thus, accurate assays are needed to determine the 225Ac/ 227Ac ratio, which is dependent on beam energy, irradiation time and target design. Accurate actinium assays, in turn, require efficient separation of actinium isotopes from both the Th matrix and highly radioactive activation by-products, especially radiolanthanides formed from proton-induced fission. In this study, we introduce a novel, selective chromatographic technique for the recovery and purification of actinium isotopes from irradiated Th matrices. A two-step sequence of cation exchange and extraction chromatography was implemented. Radiolanthanides were quantitatively removed from Ac, and no non-Ac radionuclidic impurities were detected in the final Ac fraction. An 225Ac spike added prior to separation was recovered at ≥98%,more » and Ac decontamination from Th was found to be ≥10 6. Finally, the purified actinium fraction allowed for highly accurate 227Ac determination at analytical scales, i.e., at 227Ac activities of 1–100 kBq (27 nCi to 2.7 μCi).« less

Authors:
 [1];  [1];  [1]; ORCiD logo [1]; ORCiD logo [1];  [1]; ORCiD logo [1];  [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
OSTI Identifier:
1492639
Alternate Identifier(s):
OSTI ID: 1244093
Report Number(s):
LA-UR-14-26567
Journal ID: ISSN 0021-9673
Grant/Contract Number:  
89233218CNA000001; AC52-06NA253996
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Chromatography
Additional Journal Information:
Journal Volume: 1380; Journal Issue: C; Journal ID: ISSN 0021-9673
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; 62 RADIOLOGY AND NUCLEAR MEDICINE; Thorium metal; Actinium isotopes; Thorium chelationIon exchange; Extraction chromatography; Lanthanide separation

Citation Formats

Radchenko, Valery, Engle, Jonathan W., Wilson, Justin Jeff, Maassen, Joel Ryan, Nortier, Francois Meiring, Taylor, Wayne Allen, Birnbaum, Eva R., Hudston, Lisa Ann, John, Kevin Dale, and Fassbender, Michael Ernst. Application of ion exchange and extraction chromatography to the separation of actinium from proton-irradiated thorium metal for analytical purposes. United States: N. p., 2014. Web. doi:10.1016/j.chroma.2014.12.045.
Radchenko, Valery, Engle, Jonathan W., Wilson, Justin Jeff, Maassen, Joel Ryan, Nortier, Francois Meiring, Taylor, Wayne Allen, Birnbaum, Eva R., Hudston, Lisa Ann, John, Kevin Dale, & Fassbender, Michael Ernst. Application of ion exchange and extraction chromatography to the separation of actinium from proton-irradiated thorium metal for analytical purposes. United States. doi:10.1016/j.chroma.2014.12.045.
Radchenko, Valery, Engle, Jonathan W., Wilson, Justin Jeff, Maassen, Joel Ryan, Nortier, Francois Meiring, Taylor, Wayne Allen, Birnbaum, Eva R., Hudston, Lisa Ann, John, Kevin Dale, and Fassbender, Michael Ernst. Thu . "Application of ion exchange and extraction chromatography to the separation of actinium from proton-irradiated thorium metal for analytical purposes". United States. doi:10.1016/j.chroma.2014.12.045. https://www.osti.gov/servlets/purl/1492639.
@article{osti_1492639,
title = {Application of ion exchange and extraction chromatography to the separation of actinium from proton-irradiated thorium metal for analytical purposes},
author = {Radchenko, Valery and Engle, Jonathan W. and Wilson, Justin Jeff and Maassen, Joel Ryan and Nortier, Francois Meiring and Taylor, Wayne Allen and Birnbaum, Eva R. and Hudston, Lisa Ann and John, Kevin Dale and Fassbender, Michael Ernst},
abstractNote = {We present that actinium-225 (t1/2 = 9.92 d) is an α-emitting radionuclide with nuclear properties well-suited for use in targeted alpha therapy (TAT), a powerful treatment method for malignant tumors. Actinium-225 can also be utilized as a generator for 213Bi (t1/2 45.6 min), which is another valuable candidate for TAT. Actinium-225 can be produced via proton irradiation of thorium metal; however, long-lived 227Ac (t1/2 = 21.8 a, 99% β-, 1% α) is co-produced during this process and will impact the quality of the final product. Thus, accurate assays are needed to determine the 225Ac/227Ac ratio, which is dependent on beam energy, irradiation time and target design. Accurate actinium assays, in turn, require efficient separation of actinium isotopes from both the Th matrix and highly radioactive activation by-products, especially radiolanthanides formed from proton-induced fission. In this study, we introduce a novel, selective chromatographic technique for the recovery and purification of actinium isotopes from irradiated Th matrices. A two-step sequence of cation exchange and extraction chromatography was implemented. Radiolanthanides were quantitatively removed from Ac, and no non-Ac radionuclidic impurities were detected in the final Ac fraction. An 225Ac spike added prior to separation was recovered at ≥98%, and Ac decontamination from Th was found to be ≥106. Finally, the purified actinium fraction allowed for highly accurate 227Ac determination at analytical scales, i.e., at 227Ac activities of 1–100 kBq (27 nCi to 2.7 μCi).},
doi = {10.1016/j.chroma.2014.12.045},
journal = {Journal of Chromatography},
number = C,
volume = 1380,
place = {United States},
year = {2014},
month = {12}
}

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