Design of a thorium metal target for 225Ac production at TRIUMF
Date
2019
Authors
Robertson, Andrew K. H.
Lobbezoo, Andrew
Moskven, Louis
Schaffer, Paul
Hoehr, Cornelia
Journal Title
Journal ISSN
Volume Title
Publisher
Instruments
Abstract
With recent impressive clinical results of targeted alpha therapy using 225Ac, significant
effort has been directed towards providing a reliable and sufficient supply of 225Ac to enable
widespread using of 225Ac-radiopharmaceuticals. TRIUMF has begun production of 225Ac via
spallation of thorium metal with 480 MeV protons. As part of this program, a new 225Ac-production
target system capable of withstanding the power deposited by the proton beam was designed and its
performance simulated over a range of potential operating parameters. Special attention was given
to heat transfer and stresses within the target components. The target was successfully tested in two
irradiations with a 72–73 μA proton beam for a duration of 36.5 h. The decay corrected activity at
end of irradiation (average ± standard deviation) was (524 ± 21) MBq (14.2 mCi) and (86 ± 13) MBq
(2.3 mCi) for 225Ac and 225Ra, respectively. These correspond to saturation yields of 72.5 MBq/μA
for 225Ac and 17.6 MBq/μA for 225Ra. Longer irradiations and production scale-up are planned in
the future.
Description
Keywords
actinium-225, thorium, spallation, proton target, ANSYS, targeted alpha therapy
Citation
Robertson, A. K. H., Lobbezoo, A., Moskven, L., Schaeffer, P., & Hoehr, C. (2019). “Design of a thorium metal target for 225Ac production at TRIUMF.” Instruments, 3(1), 18. https://doi.org/10.3390/instruments3010018