18F−THK−5351 ; Tau imaging ; Fluorine-18 ; PET ; Radiotracer ; Automation
Abstract
18F−THK−5351
18F−THK−5351
is a PET radiotracer to image the hyperphosphorylated tau fibrillar aggregates in human brain. This protocol describes the optimized radiosynthesis of 18F−THK−5351
18F−THK−5351
using a commercial GE TRACERlabTM
TRACERlabTM
FXFN
FXFN
radiosynthesis module. 18F−THK−5351
18F−THK−5351
was prepared by nucleophilic [18F
18F
]fluorination from its protected tosylate precursors, (S)-(2-(2-methylaminopyrid-5-yl)-6-[[2-(tetrahydro-2H-pyran-2-yloxy)-3-tosyloxy]propoxy] quinolone(THK-5352), at 110∘C
110∘C
for 10 min in dimethyl sulfoxide, followed by deprotection with 1 N HCl. The average radiochemical yield of 18F−THK−5351
18F−THK−5351
was 31.9±6.7
31.9±6.7
(decay-corrected, n = 10), with molar activity of 198.1±33.9GBq/μmol
198.1±33.9GBq/μmol
(5.4±0.9Ci/μmol
5.4±0.9Ci/μmol
, n = 10). The radiochemical purity was determined to be above 98%. The overall production time including HPLC purification is approximately 70 min. This fully-automated protocol is validated for clinical use.