Design of a Thorium Metal Target for <sup>225</sup>Ac Production at TRIUMF

oleh: Andrew K.H. Robertson, Andrew Lobbezoo, Louis Moskven, Paul Schaffer, Cornelia Hoehr

Format: Article
Diterbitkan: MDPI AG 2019-02-01

Deskripsi

With recent impressive clinical results of targeted alpha therapy using <sup>225</sup>Ac, significant effort has been directed towards providing a reliable and sufficient supply of <sup>225</sup>Ac to enable widespread using of <sup>225</sup>Ac-radiopharmaceuticals. TRIUMF has begun production of <sup>225</sup>Ac via spallation of thorium metal with 480 MeV protons. As part of this program, a new <sup>225</sup>Ac-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&#8315;73 &#181;A proton beam for a duration of 36.5 h. The decay corrected activity at end of irradiation (average &#177; standard deviation) was (524 &#177; 21) MBq (14.2 mCi) and (86 &#177; 13) MBq (2.3 mCi) for <sup>225</sup>Ac and <sup>225</sup>Ra, respectively. These correspond to saturation yields of 72.5 MBq/&#181;A for <sup>225</sup>Ac and 17.6 MBq/&#181;A for <sup>225</sup>Ra. Longer irradiations and production scale-up are planned in the future.