A theoretical model for the production of Ac-225 for cancer therapy by neutron capture transmutation of Ra-226

• Published in: Applied radiation and isotopes Vol. 72; pp. 152 - 157
• Main Authors: Melville, G., Melville, P.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2013
• Subjects: Ac-225; Neutron irradiation; Nuclear reactor; Ra-225; Ra-226; Targeted alpha therapy; Ra-226; Ac-225; Neutron irradiation; Targeted alpha therapy; Ra-225; Nuclear reactor
• ISSN: 0969-8043; 1872-9800
• DOI: 10.1016/j.apradiso.2012.09.019

Radium needles that were once implanted into tumours as a cancer treatment are now obsolete and constitute a radioactive waste problem, as their half-life is 1600 years. We are investigating the reduction of radium by transmutation by bombarding Ra-226 with high-energy neutrons from a neutron source to produce Ra-225 and hence Ac-225, which can be used as a generator to produce Bi-213 for use in ‘Targeted Alpha Therapy’ for cancer. This paper examines the possibility of producing Ac-225 by neutron capture using a theoretical model in which neutron energy is convoluted with the corresponding neutron cross sections of Ra-226. The total integrated yield can then be obtained. This study shows that an intense beam of high-energy neutrons could initiate neutron capture on Ra-226 to produce Ra-225 and hence practical amounts of Ac-225 and a useful reduction of Ra-226. ► Ra-226 was irradiated with reactor neutrons in simulations. ► Ra-225 yields were calculated for neutron energies between 8MeV and 12.5MeV. ► Fast Breeder reactors supply a greater neutron flux at higher energies. ► Commercial quantities of Ra-225 could be produced from grams of Ra-226 in days.