AVS 65th International Symposium & Exhibition
    Actinides and Rare Earths Focus Topic Wednesday Sessions
       Session AC+AS+SA-WeA

Invited Paper AC+AS+SA-WeA7
Spectroscopic Studies of Trivalent Actinide Coordination

Wednesday, October 24, 2018, 4:20 pm, Room 202C

Session: Chemistry and Physics of the Actinides and Rare Earths
Presenter: Benjamin Stein, Los Alamos National Laboratory
Authors: B.W. Stein, Los Alamos National Laboratory
M.G. Kerlin, Los Alamos National Laboratory
A.L. Morgenstern, Los Alamos National Laboratory
E. Batista, Los Alamos National Laboratory
S.E. Bone, Los Alamos National Laboratory
S.K. Cary, Los Alamos National Laboratory
J. Lezama Pacheco, SLAC National Accelerator Laboratory
S.A. Kozimor, Los Alamos National Laboratory
P. Yang, Los Alamos National Laboratory
Correspondent: Click to Email
Radioisotopes have a rich history in medicine, with their use dating back to the earliest studies of radioactivity. Only recently, however, have α-particle emitting radionuclides been considered for medical applications. Targeted alpha therapy utilizes the unique properties of α-emitting radionuclides to selectively kill cancer cells, with the short range of α-particles causing minimal collateral damage to nearby healthy cells. Actinium-225 (225Ac) has been identified by the Department of Energy Isotope Program Long Range plan as an isotope of high national interest for targeted alpha therapy, due to its favorable half-life (10 days) and 4 α-emissions in the decay chain. However, if the 225Ac is not securely bound to the targeting vector this effectiveness results in very high toxicity to off-target (i.e. healthy) cells. Due to the high radioactivity and limited supply of all actinium isotopes, very little fundamental chemistry is known about this elusive element. Utilizing the unique radiological facilities at Los Alamos, we have been able to use microscopic amounts (~30 micrograms) of the longer-lived isotope actinium-227 (half-life of 22 years) for chemical studies. Utilizing this isotope, we have developed handling and containment techniques to perform "classic" spectroscopic and chemical studies in support of developing actinium chelates to advance the use of 225Ac in targeted alpha therapy. During these studies of actinium coordination chemistry we have also made comparisons with the more "traditional" trivalent actinides, in particular americium and curium. We will discuss our latest EXAFS, NMR, and computational results on these difficult to handle elements by presenting a comparison of acetate and phosphonate binding, and how this informs chelator development.