When beta therapy fails – Is alpha therapy a solution? Actinium-225 production and applications

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Jonathan Fitzsimmons

Brookhaven National Lab Upton USA

: J Diagn Tech Biomed Anal

Abstract

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A ctinium-225 ( 225 Ac) has a half life of 9.92 days, decaying through multiple intermediate nuclei to a daughter isotope Bismuth-213 ( 213 Bi) with a half life of 45 min. Both isotopes have been investigated for targeted alpha therapy. Researchers have shown 213 Bi DOTATOC can shrink tumors in patients that had previously not responded to similar treatments with the beta emitting isotopes 90 Y and 177 Lu. The United States Department of Energy (US DOE) supplies purified 225 Ac from a generator system associated with the parent isotope 229 Th, but this approach does not supply enough 225 Ac for the applications associated with both 225 Ac and 213 Bi. To meet this demand the US DOE has initiated a Tri-lab (Los Alamos-Brookhaven-Oak Ridge National Laboratories) effort to develop 225 Ac by irradiation of a thorium target with high energy (90-200 MeV) protons. One of the main challenges associated with this production route is isolation of 225 Ac from bulk thorium and other radionuclides (~400) formed as a result of fission and other nuclear reactions. In targeted alpha therapy with 225 Ac the retention of the multiple daughters of 225 Ac at the target site has been problematic. A chemical method to produce a targeting nanochelator to: capture 225 Ac, retain the daughters of alpha decay, and target tumors will be discussed

Biography

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Jonathan Fitzsimmons completed his Master from Johns Hopkins University in 2000, and received his PhD in Radiochemistry in 2005 from University of Missouri-Columbia. He performed Postdoctoral studies at Los Alamos National Laboratory and research at the University of North Carolina at Chapel Hill. He is currently a Medical Scientist at Brookhaven National Laboratory, where he developed a production scale separation of 68Ge, and is a part of the TriLab team to develop 225 Ac on a production scale. He has published over ten papers in reputed journals, has one patent and is serving on an expert panel for the US Pharmacopeia.

E-Mail: jfitzsimmons@bnl.gov