Speaker
Description
$^{225}$Ac has been identified as a promising isotope for Targeted Alpha Therapy (TAT) treatment of metastasized tumors [1]. For logistic and medical purposes, a better understanding of the nuclear data along the entire $^{225}$Ac decay chain is required. Currently discrepancies are observed when measuring the activity using techniques that utilize different daughter nuclides and different methods. As an attempt to resolve these discrepancies, the IS741 collaboration aims to determine the decay properties along the decay chain by implanting specific isotopes of the decay sequence ($^{225}$Ac, $^{221}$Fr, $^{213}$Bi and $^{209}$Tl) separately in dedicated beam times [2]. For this, the ISOLDE Decay Station (IDS) was employed utilizing its tape station for the implantations [3]. Special focus was put on extracting the angular distribution of coincident $\gamma$-rays, by placing twelve HPGe detectors in defined angles around the implantation point. The study of $^{225}$Ac and $^{221}$Fr was performed in December 2024, and the $^{213}$Bi and $^{209}$Tl experiment is planned as the last experiment before LS3. This contribution will discuss the current status of the IS741 experiment.
References:
[1] C. Kratochwil et al., “225Ac-PSMA-617 for PSMA-Targeted α-Radiation Therapy of Metastatic Castration-Resistant Prostate Cancer,” Journal of Nuclear Medicine, 2016.
[2] A. Algora et al., “Proposal to the isolde and neutron time-of-flight committee: Detailed decay spectroscopy of 225ac and its daughters to support its use in medical applications,” European Organization for Nuclear Research (CERN), Geneva, Switzerland, Research Proposal CERN-INTC-2023-063, 2023.
[3] ISOLDE Decay Station (IDS) Collaboration, Isolde decay station (ids), https://isolde-ids.web.cern.ch/, accessed: 2025-10-13, 2025.
