Cyclotron production of 225Ac from an electroplated 226Ra target

Purpose We demonstrate cyclotron production of high-quality 225Ac using an electroplated 226Ra target. Methods 226Ra was extracted from legacy Ra sources using a chelating resin. Subsequent ion-exchange purification gave pure 226Ra with a certain amount of carrier Ba. The radium target was prepared by electroplating. We successfully deposited about 37 MBq of 226Ra 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 225Ac and recovered 226Ra. Cooling the intermediate 225Ac for 2–3 weeks decayed the major byproduct of 226Ac and increased the radionuclidic purity of 225Ac. Repeating the same separation protocol provided high-quality 225Ac. Results We obtained 225Ac at a yield of about 2.4 MBq at the end of bombardment (EOB), and the subsequent initial purification gave 1.7 MBq of 225Ac with 226Ac/225Ac ratio of < 3% at 4 days from EOB. Additional cooling time coupled with the separation procedure (secondary purification) effectively increased the 225Ac (4n + 1 series) radionuclidic purity up to 99 + %. The recovered 225Ac had a similar identification to commercially available 225Ac originating from a 229Th/225Ac generator. Conclusion This procedure, which involves the 226Ra(p,2n)225Ac reaction and the appropriate purification, has the potential to be a major alternative pathway for 225Ac production because it can be performed in any facility with a compact cyclotron to address the increasing demand for 225Ac.

Cyclotron Production of 225Ac from an electroplated 226Ra Target

Purpose We demonstrate a cyclotron production of high-quality 225Ac using an electroplated 226Ra target. Methods All 226Ra used in this work was extracted from legacy Ra sources using a chelating resin. The subsequent ion-exchange purification gave pure 226Ra with a certain amount of carrier Ba. The radium target was prepared by electroplating. We successfully deposited about 1 mg (mCi) of 226Ra on a target box. Activation was performed by 16.5 MeV protons (on the target) at 20 µA for 5 h as the maximum. Purification of 225Ac as well as 226Ra recovery was performed using two functional resins with various concentrations of nitric acid. Cooling of the intermediate 225Ac for 2–3 weeks decayed the major byproduct of 226Ac and increased the radionuclidic purity of 225Ac. Then the same separation protocol was repeated to provide high-quality 225Ac. Results We obtained 225Ac at a yield of about 2.4 MBq (65 µCi) at EOB, and the subsequent primal purification gave 1.7 MBq (48 µCi) of 225Ac with 226Ac/225Ac ratio of < 4% at 4 d from EOB. Additional cooling time coupled with the repeated separation procedure (secondary purification) effectively increased the 225Ac (4n + 1 series) radionuclidic purity up to 99+%, which showed a similar identification to a commercially available 225Ac originating from a 229Th/225Ac generator. Conclusion The 226Ra(p,2n)225Ac reaction and the appropriate purification procedure has the potential to be a major alternative pathway for 225Ac production and can be performed in any facility with a compact cyclotron to address the increasing demand for 225Ac.

Choice of accelerator type for Boron Neutron Capture Therapy system

There are briefly considered physical and medical aspects contemporary development of Boron Neutron Capture Therapy (BNCT) system. Choice of accelerator for neutron produce is discussed. Three of accelerator types are compared: electrostatic accelerator, compact cyclotron and RFQ with working frequency of P-diapason. A few factors determine choice: providing required neutron flux, compactness of accelerator and whole BNCT system, economical power consumption. Our choice is radio-frequency quadrupole. Two of RFQ variants are considered: compact RFQ and universal one, which has possibility to accelerate two of types particles (proton and deuteron) and to use two of types targets (Lithium and Beryllium) for neutron production.