Cyclotron production of 225Ac from an electroplated 226Ra target
Kotaro Nagatsu, Hisashi Suzuki, Masami Fukada, Taku Ito, Jun Ichinose, Yoshio Honda, Katsuyuki Minegishi, Tatsuya Higashi, Ming‐Rong Zhang
Abstract
Abstract Purpose We demonstrate cyclotron production of high-quality 225 Ac using an electroplated 226 Ra target. Methods 226 Ra was extracted from legacy Ra sources using a chelating resin. Subsequent ion-exchange purification gave pure 226 Ra with a certain amount of carrier Ba. The radium target was prepared by electroplating. We successfully deposited about 37 MBq of 226 Ra on a target box. Maximum activation was achieved using 15.6 MeV protons on the target at 20 µA for 5 h. Two functional resins with various concentrations of nitric acid purified 225 Ac and recovered 226 Ra. Cooling the intermediate 225 Ac for 2–3 weeks decayed the major byproduct of 226 Ac and increased the radionuclidic purity of 225 Ac. Repeating the same separation protocol provided high-quality 225 Ac. Results We obtained 225 Ac at a yield of about 2.4 MBq at the end of bombardment (EOB), and the subsequent initial purification gave 1.7 MBq of 225 Ac with 226 Ac/ 225 Ac ratio of < 3% at 4 days from EOB. Additional cooling time coupled with the separation procedure (secondary purification) effectively increased the 225 Ac (4n + 1 series) radionuclidic purity up to 99 + %. The recovered 225 Ac had a similar identification to commercially available 225 Ac originating from a 229 Th/ 225 Ac generator. Conclusion This procedure, which involves the 226 Ra(p,2n) 225 Ac reaction and the appropriate purification, has the potential to be a major alternative pathway for 225 Ac production because it can be performed in any facility with a compact cyclotron to address the increasing demand for 225 Ac.