Elisabeth Oehlke1, Cornelia Hoehr2, Xinchi Hou3, Victoire Hanemaayer2, Stefan Zeisler2, Michael J Adam2, Thomas J Ruth4, Anna Celler3, Ken Buckley2, Francois Benard5, Paul Schaffer6. 1. TRIUMF, 4004 Wesbrook Mall, V6T 2A3, Vancouver, BC, Canada; Delft University of Technology, Mekelweg 15, 2629 JB Delft, The Netherlands. Electronic address: e.oehlke@tudelft.nl. 2. TRIUMF, 4004 Wesbrook Mall, V6T 2A3, Vancouver, BC, Canada. 3. University of British Columbia, 3350-950W. 10th Avenue, Vancouver, BC, V5Z 4E3, Canada. 4. TRIUMF, 4004 Wesbrook Mall, V6T 2A3, Vancouver, BC, Canada; British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, BC, V5Z 1L3, Canada. 5. British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, BC, V5Z 1L3, Canada; University of British Columbia, 3350-950W. 10th Avenue, Vancouver, BC, V5Z 4E3, Canada. 6. TRIUMF, 4004 Wesbrook Mall, V6T 2A3, Vancouver, BC, Canada; University of British Columbia, 3350-950W. 10th Avenue, Vancouver, BC, V5Z 4E3, Canada.
Abstract
INTRODUCTION: Diagnostic radiometals are typically obtained from cyclotrons by irradiating solid targets or from radioisotope generators. These methods have the advantage of high production yields, but require additional solid target handling infrastructure that is not readily available to many cyclotron facilities. Herein, we provide an overview of our results regarding the production of various positron-emitting radiometals using a liquid target system installed on a 13 MeV cyclotron at TRIUMF. Details about the production, purification and quality control of (89)Zr, (68)Ga and for the first time (86)Y are discussed. METHODS: Aqueous solutions containing 1.35-1.65 g/mL of natural-abundance zinc nitrate, yttrium nitrate, and strontium nitrate were irradiated on a 13 MeV cyclotron using a standard liquid target. Different target body and foil materials were investigated for corrosion. Production yields were calculated using theoretical cross-sections from the EMPIRE code and compared with experimental results. The radioisotopes were extracted from irradiated target material using solid phase extraction methods adapted from previously reported methods, and used for radiolabelling experiments. RESULTS: We demonstrated production quantities that are sufficient for chemical and biological studies for three separate radiometals, (89)Zr (Asat = 360 MBq/μA and yield = 3.17 MBq/μA), (86)Y (Asat = 31 MBq/μA and yield = 1.44 MBq/μA), and (68)Ga (Asat = 141 MBq/μA and yield = 64 MBq/μA) from one hour long irradiations on a typical medical cyclotron. (68)Ga yields were sufficient for potential clinical applications. In order to avoid corrosion of the target body and target foil, nitrate solutions were chosen as well as niobium as target-body material. An automatic loading system enabled up to three production runs per day. The separation efficiency ranged from 82 to 99%. Subsequently, (68)Ga and (86)Y were successfully used to radiolabel DOTA-based chelators while deferoxamine was used to coordinate (89)Zr.
INTRODUCTION: Diagnostic radiometals are typically obtained from cyclotrons by irradiating solid targets or from radioisotope generators. These methods have the advantage of high production yields, but require additional solid target handling infrastructure that is not readily available to many cyclotron facilities. Herein, we provide an overview of our results regarding the production of various positron-emitting radiometals using a liquid target system installed on a 13 MeV cyclotron at TRIUMF. Details about the production, purification and quality control of (89)Zr, (68)Ga and for the first time (86)Y are discussed. METHODS: Aqueous solutions containing 1.35-1.65 g/mL of natural-abundance zinc nitrate, yttrium nitrate, and strontium nitrate were irradiated on a 13 MeV cyclotron using a standard liquid target. Different target body and foil materials were investigated for corrosion. Production yields were calculated using theoretical cross-sections from the EMPIRE code and compared with experimental results. The radioisotopes were extracted from irradiated target material using solid phase extraction methods adapted from previously reported methods, and used for radiolabelling experiments. RESULTS: We demonstrated production quantities that are sufficient for chemical and biological studies for three separate radiometals, (89)Zr (Asat = 360 MBq/μA and yield = 3.17 MBq/μA), (86)Y (Asat = 31 MBq/μA and yield = 1.44 MBq/μA), and (68)Ga (Asat = 141 MBq/μA and yield = 64 MBq/μA) from one hour long irradiations on a typical medical cyclotron. (68)Ga yields were sufficient for potential clinical applications. In order to avoid corrosion of the target body and target foil, nitrate solutions were chosen as well as niobium as target-body material. An automatic loading system enabled up to three production runs per day. The separation efficiency ranged from 82 to 99%. Subsequently, (68)Ga and (86)Y were successfully used to radiolabel DOTA-based chelators while deferoxamine was used to coordinate (89)Zr.
Authors: Melissa E Rodnick; Carina Sollert; Daniela Stark; Mara Clark; Andrew Katsifis; Brian G Hockley; D Christian Parr; Jens Frigell; Bradford D Henderson; Monica Abghari-Gerst; Morand R Piert; Michael J Fulham; Stefan Eberl; Katherine Gagnon; Peter J H Scott Journal: EJNMMI Radiopharm Chem Date: 2020-11-12