Production of Y-86 and other radiometals for research purposes using a solution target system.
BACKGROUND
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.
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.
Elisabeth
E
Oehlke
TRIUMF, 4004 Wesbrook Mall, V6T 2A3, Vancouver, BC, Canada.
Cornelia
C
Hoehr
University of British Columbia, 3350-950W. 10th Avenue, Vancouver, BC, V5Z 4E3, Canada.
Xinchi
X
Hou
TRIUMF, 4004 Wesbrook Mall, V6T 2A3, Vancouver, BC, Canada.
Victoire
V
Hanemaayer
TRIUMF, 4004 Wesbrook Mall, V6T 2A3, Vancouver, BC, Canada.
Stefan
S
Zeisler
TRIUMF, 4004 Wesbrook Mall, V6T 2A3, Vancouver, BC, Canada.
Michael J
MJ
Adam
TRIUMF, 4004 Wesbrook Mall, V6T 2A3, Vancouver, BC, Canada; British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, BC, V5Z 1L3, Canada.
Thomas J
TJ
Ruth
University of British Columbia, 3350-950W. 10th Avenue, Vancouver, BC, V5Z 4E3, Canada.
Anna
A
Celler
TRIUMF, 4004 Wesbrook Mall, V6T 2A3, Vancouver, BC, Canada.
Ken
K
Buckley
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.
Francois
F
Benard
TRIUMF, 4004 Wesbrook Mall, V6T 2A3, Vancouver, BC, Canada; University of British Columbia, 3350-950W. 10th Avenue, Vancouver, BC, V5Z 4E3, Canada.
Paul
P
Schaffer
D011232:Chemical Precipitation; D017357:Cyclotrons; D011786:Quality Control; D011854:Radiochemistry / Q000295:instrumentation / Q000379:methods*; D012492:Salts / Q000737:chemistry; D012996:Solutions; D015021:Yttrium Radioisotopes / Q000737:chemistry* / Q000302:isolation & purification
D012492:Salts; D012996:Solutions; D015021:Yttrium Radioisotopes
(86)Y; PET; Radioisotope production; Radiometal; Targetry; Yttrium-86