Production of 230Pa by proton irradiation of 232Th at the LANL isotope production facility: Precursor of 230U for targeted alpha therapy.

Uranium-230 (t1/2 = 20.8 d) is an alpha-emitting radionuclide that has potential application in targeted alpha therapy (TAT) of cancer. Its parent isotope 230Pa (t1/2 = 17.4 d), can be produced by proton irradiation of thorium metal targets. Preliminary 230Pa production runs were performed at the Los Alamos National Laboratory Isotope Production Facility (LANL-IPF) using thin thorium metal targets and a proton beam energy of 15-30 MeV, followed by radiochemical separation of 230Pa from the irradiated target matrix. The measured 230Pa production yields were found to exceed the predicted values in most of the experiments that were performed. This data will inform further production efforts for providing 230Pa/230U for clinical trials.