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Research Article
Kotaro Nagatsu
National Institutes for Quantum and Radiological Science and Technology: Kokuritsu Kenkyu Kaihatsu Hojin Ryoshi Kagaku Gijutsu Kenkyu Kaihatsu Kiko
Corresponding Author
License:
This work is licensed under a CC BY 4.0 License. Read Full License
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.
Keywords
Actinium-225, Radium-226, Alpha emitter, Targeted alpha therapy
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CURRENT STATUS: Under Revision
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Posted 04 Mar, 2021
No community comments so far
Editorial decision: Major Revision
On 25 Mar, 2021
Reviewers invited
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Received 27 Feb, 2021
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This preprint is under consideration at European Journal of Nuclear Medicine and Molecular Imaging. A preprint is a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Learn more about In Review
Research Article
Kotaro Nagatsu
National Institutes for Quantum and Radiological Science and Technology: Kokuritsu Kenkyu Kaihatsu Hojin Ryoshi Kagaku Gijutsu Kenkyu Kaihatsu Kiko
Corresponding Author
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Under Revision
Version 1
Posted 04 Mar, 2021
No community comments so far
Editorial decision: Major Revision
On 25 Mar, 2021
Reviewers invited
Invitations sent on 27 Feb, 2021
Review #? received
Received 27 Feb, 2021
First submitted
On 24 Feb, 2021
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
License:
This work is licensed under a CC BY 4.0 License. Read Full License
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.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
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