From Beamline to Scanner with $^{225}$Ac

Due to the high linear energy transfer and short range of alpha-radiation, targeted radiation therapy using alpha-emitting pharmaceuticals that successfully target small disease clusters will kill target cells with limited harm to healthy tissue, potentially treating the most aggressive forms of cancer. As the parent of a decay chain with four alpha- and two beta-decays, $^{225}$Ac is a promising candidate for such a treatment. However, this requires retention of the entire decay chain at the target site, preventing the creation of freely circulating alpha-emitters that reduce therapeutic effect and increase toxicity to non-target tissues. Two major challenges to $^{225}$Ac pharmaceutical development exist: insufficient global supply, and the difficulty of preventing toxicity by retaining the entire decay chain at the target site. While TRIUMF works towards large-scale (\~ Ci amounts) production of $^{225}$Ac, we already use our Isotope Separation On-Line facility to provide small ($<$ 1 mCi) quantities for in-house chemistry and imaging research that aims to improve and assess $^{225}$Ac radiopharmaceutical targeting. This presentation provides an overview of this research program and the journey of $^{225}$Ac from the beamline to the scanner.