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Updated: Dec 14, 2025
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Preparing an Isotopically Pure 229Th Ion Beam for Studies of 229mTh
Published on: May 3, 2019
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232Th-Spallation-Produced 225Ac with Reduced 227Ac Content
Andrew K H Robertson1,2, Brooke L McNeil2,3, Hua Yang2
1Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1.
Inorganic Chemistry
|July 18, 2020
Summary
Researchers developed a new method to produce high-purity actinium-225 (225Ac) for cancer therapy. This process significantly reduces the problematic actinium-227 (227Ac) byproduct, improving the quality of 225Ac generators.
Area of Science:
- Nuclear medicine
- Radiochemistry
- Medical physics
Background:
- Actinium-225 (225Ac) is a promising alpha-emitter for targeted cancer therapy.
- Current production methods for 225Ac face challenges with low yields and the co-production of impurities like actinium-227 (227Ac).
- Accelerator-based production of 225Ac from thorium irradiation generates undesirable 227Ac.
Purpose of the Study:
- To develop an improved method for producing 225Ac with reduced 227Ac content.
- To create a 225Ra/225Ac generator system yielding high-purity 225Ac.
- To evaluate the quality and radiolabeling capabilities of the produced 225Ac.
Main Methods:
- Irradiation of thorium targets with high-energy protons.
- Separation of 225Ac from irradiated thorium and other radioactive products using thorium peroxide precipitation, cation exchange, and extraction chromatography.
- Development of a two-stage purification process to obtain both directly and indirectly produced 225Ac.
Main Results:
- A directly produced 225Ac product with a measured 227Ac content of (0.15 ± 0.04)% was achieved.
- An indirectly produced 225Ac product from a 225Ra generator showed significantly lower 227Ac content (<7.5 × 10-5%).
- The indirectly produced 225Ac demonstrated comparable or improved chemical purity and radiolabeling efficiency.
Conclusions:
- The developed thorium peroxide precipitation and chromatographic separation method effectively reduces 227Ac contamination in 225Ac production.
- The 225Ra/225Ac generator system provides a high-quality 225Ac source suitable for clinical applications.
- This advancement supports the increased availability of high-purity 225Ac for targeted alpha therapy.
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