Accelerator Based Production of $^{225}$Ac for Cancer Treatment

Abstract

Targeted Alpha Therapy potentially offers a more specific action in killing tumor cells and less damage to neighbouring normal cells compared to β-emitters. 225 Ac along with three other αemitting daughter nuclei 221 Fr, 217 At and 213 Po have significant potency for clinical use. Monte carlo simulation has been carried out using MONC code for production routes of 225 Ac for its possible generation using proton accelerators with Thorium-232 and Radium-226 targets. All the calculations has been carried out using global model parameters without adjusting for individual target. The study reveals that proton beam of 20-30MeV energy with 5µA current on radium-226 target can give rise to 1Ci of 225 Ac activity in a week of irradiation. Thorium irradiation at low proton energy produces smaller 225 Ac activity but one can benefit from high current, stable proton accelerators. Proton energy of 100MeV or above with hundreds of µA current can produce reasonable 225 Ac activity for practical use. However, the contamination of other co-produced radioisotopes is much less at low proton energy hence low energy high current proton accelerators are also viable alternative to generate Actinium-225 radio isotope.

Production of 225Ac for medical application from 232Th-metallic targets in Nb-shells irradiated with middle-energy protons

“…There are about 15 projects worldwide for the production of 225 Ac or 229 Th from 226 Ra-containing targets. 17 Different methods are reported, in particular irradiation of radiumcontaining targets with protons, [18][19][20] deuterons, 21 gamma quanta 22 or neutrons 23,24 followed by the recovery of 225 Ac or 229 Th from the irradiated targets by ion exchange and other chemical methods. Generally, radium salts, e.g., carbonate, nitrate or chloride are used as target materials.…”