Theoretical Prediction of the Preferred Production Routes of 225Ac from Proton Induced Reactions on 232Th

Abstract

Alpha emitting radionuclides have potential for the therapy of cancers because of their high linear energy transfer, and short range biologic effectiveness. Alpha emitter 225Ac(T1/2 = 10.0 days) is a potent nuclide for targeted radionuclide therapy. 225Ac excitation functions via 232Th (p,7np)225Th→225Ac, 232Th (p,6n2p)225Ac, 232Th (p,4nα)225Ac, 232Th (p,5n3p)225Th→ 225Ac, and 232Th (p,3nαp)225Ra→225Ac  reactions were calculated by Empire 3.2 code up to 200MeV and compared with existing data. No single nuclear level density with a pre-equilibrium model produce results which agree with the existing experimental data all through the energy range. However, a hybrid of the different nuclear level densities with the Hybrid Monte Carlo Simulation (HMS) and the exciton PCROSS pre-equilibrium models at different energy range provide results which are in good agreement with the existing experimental data. Hence the preferred production route for the direct and indirect production of 225Ac has also been suggested.