2-7 June 2019
Simon Fraser University
America/Vancouver timezone
Welcome to the 2019 CAP Congress Program website! / Bienvenue au siteweb du programme du Congrès de l'ACP 2019 !

Production and purification of radium-225 and actinium-225 at TRIUMF’s Isotope Separation On-line (ISOL) facility and subsequent radiolabeling studies with alpha-emitter actinium-225

4 Jun 2019, 13:15
30m
SCC 9000 (Simon Fraser University)

SCC 9000

Simon Fraser University

Invited Speaker / Conférencier(ère) invité(e) Symposia Day - Nuclear Astrophysics and Medical Isotopes (in honour of Prof. John D'Auria) T3-3 Nuclear Astrophysics/Structure and Medical Isotopes in honour of Prof. John D'Auria PM-1 (DNP) | Astrophysique nucléaire / Structure et isotopes médicaux en hommage au prof. John D'Auria PM-1 (DPN)

Speaker

Caterina Ramogida (Simon Fraser University)

Description

With four alpha particles in its decay chain, actinium-225 (225Ac; t1/2 = 9.9 d) is a promising candidate isotope for Targeted Alpha Therapy (TAT) when coupled with a disease targeting vector. The current limited global supply of 225Ac (67 GBq/year), and lack of appropriate chelating ligands able to complex this isotope has delayed the advancement of 225Ac-drugs towards the clinic [1]. Herein, we describe efforts to produce, purify, and evaluate the radiolabeling ability of 225Ac, by leveraging TRIUMF’s ISAC isotope separation on-line (ISOL) facility. 225Ac alongside, parent nuclide radium-225 ( 225Ra; t1/2 = 14.8 d), were produced via spallation of uranium carbide targets with 480 MeV protons on ISOL’s radioactive beam facility. Downstream from the target, a high-resolution mass separator was used to isolate 225Ra and 225Ac ions from other isotopes produced in the spallation process. The 28 keV beam was directed towards an aluminum holder in which the ions were implanted at a depth between 10 and 30 nm. Implantation yields of 1.6x108 and 5.7x107 ions/s resulted in isolation of 1.0 – 7.5 and 1.4 – 18.0 MBq of 225Ra and 225Ac, respectively. The implanted activity was etched off the sample stage with dilute acid, and 225Ac was separated in >99% yield from 225Ra using solid phase extraction (DGA resin) [2]. This method has resulted in the isolation of MBq quantities of both 225Ra and 225Ac, where the former can be stored and used as a generator for 225Ac. Subsequently, 225Ac coordination properties with a library of acyclic chelators based on picolinic acids (such as H4(CHX)octapa [3],[4] [N4O4], and H6phospa [5] [N4O6]) along with commercial standard DOTA (N4O4) were evaluated by testing radiolabeling efficiency, and complex stability. In conclusion, we have successfully established a production method for 225Ac which yields activities adequate for pre-clinical screening. Furthermore, several novel actinium-chelators showed promising 225Ac radiolabeling properties and kinetic inertness in vitro compared to DOTA, and will be tested in vivo in future studies.

Primary author

Caterina Ramogida (Simon Fraser University)

Co-authors

Andrew K.H. Robertson (UBC) Peter Kunz (TRIUMF) Una Jermilova (TRIUMF) Jens Lassen (TRIUMF) Ivica Bratanovic (TRIUMF) Victoria Brown (TRIUMF) Valery Radchenko (TRIUMF) Chris Orvig (UBC) Paul Schaffer (TRIUMF)

Presentation Materials