In-vivo imaging characteristics of two fluorinated flumazenil radiotracers in the rat

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dc.contributor.authorDedeurwaerdere, Sen_AU
dc.contributor.authorGrégoire, MCen_AU
dc.contributor.authorVivash, Len_AU
dc.contributor.authorRoselt, Pen_AU
dc.contributor.authorBinns, Den_AU
dc.contributor.authorFookes, CJRen_AU
dc.contributor.authorGreguric, Ien_AU
dc.contributor.authorPham, TQen_AU
dc.contributor.authorLoc'h, Cen_AU
dc.contributor.authorKatsifis, Aen_AU
dc.contributor.authorHicks, RJen_AU
dc.contributor.authorO'Brien, TJen_AU
dc.contributor.authorMyers, DEen_AU
dc.date.accessioned2010-04-01T05:43:00Zen_AU
dc.date.accessioned2010-04-30T05:08:03Zen_AU
dc.date.available2010-04-01T05:43:00Zen_AU
dc.date.available2010-04-30T05:08:03Zen_AU
dc.date.issued2009-06en_AU
dc.date.statistics2009-06en_AU
dc.description.abstractPurpose: [11C]Flumazenil shows promise as a clinical and research PET radiotracer to image changes in GABAA central benzodiazepine receptor (cBZR), but its widespread use has been limited by practical limitations of [11C]. This study evaluated the imaging characteristics of two fluorinated PET radiotracers in rats in vivo: [18F]fluoroflumazenil ([18F]FFMZ) and [18F]flumazenil ([18F]FMZ). Methods: PET acquisitions were performed on a small-animal scanner following injection of [18F]FFMZ in nine rats and [18F]FMZ in eight rats. The following treatments were investigated: (1) injection of the tracer dose, (2) presaturation then injection of the tracer dose, and (3) injection of the tracer dose followed by a displacement injection. Unchanged tracer was measured in plasma and brain structures in four animals 10 and 30 min after injection, and ex-vivo autoradiography was also performed. Results: For both [18F]FFMZ and [18F]FMZ maximal brain activity peaked rapidly, and was highest in the hippocampus (1.12±0.06 SUV, 1.24±0.10 SUV, respectively), and lowest in the pons (1.00±0.07 SUV, 1.03±0.09 SUV, respectively). By 50 min after injection, maximal uptake for [18F]FFMZ and [18F]FMZ had decreased in the hippocampus to 18±3% and 80±1% (p<0.01), respectively. The presaturation and displacement studies showed a higher nonspecific component for [18F]FFMZ than for [18F]FMZ. Metabolite studies showed that at 30 min only 10% of the signal was from [18F]FFMZ in the brain. This nonspecific binding was apparent on autoradiography. In contrast, [18F]FMZ accounted for >70% of the signal in the brain, which resulted in well-defined regional binding on autoradiography. Conclusion These results demonstrate that [18F]FMZ is a superior radiotracer to [18F]FFMZ for in-vivo PET imaging of the GABAA/cBZR, having slower metabolism and leading to lower concentrations of metabolites in the brain that results in a substantially better signal-to-noise ratio. © 2009, Springer.en_AU
dc.identifier.citationDedeurwaerdere, S.,Grégoire , M. C., Vivash, L., Roselt, P., Binns, D., Fookes, C., Greguric, I., Pham, T., Loc'h, C., Katsifis, A., Hicks, R. J., O'Brien, T. J., & Myers, D. E. (2009). In-vivo imaging characteristics of two fluorinated flumazenil radiotracers in the rat. European Journal of Nuclear Medicine and Molecular Imaging, 36(6), 958-965. doi:10.1007/s00259-009-1066-4en_AU
dc.identifier.govdoc1517en_AU
dc.identifier.issn619-7070en_AU
dc.identifier.issue6en_AU
dc.identifier.journaltitleEuropean Journal of Nuclear Medicine and Molecular Imagingen_AU
dc.identifier.pagination958-965en_AU
dc.identifier.urihttp://dx.doi.org/10.1007/s00259-009-1066-4en_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/3025en_AU
dc.identifier.volume36en_AU
dc.language.isoenen_AU
dc.publisherSpringeren_AU
dc.subjectRatsen_AU
dc.subjectRadiopharmaceuticalsen_AU
dc.subjectTracer techniquesen_AU
dc.subjectIn vivoen_AU
dc.subjectPositron computed tomographyen_AU
dc.subjectFluorinationen_AU
dc.titleIn-vivo imaging characteristics of two fluorinated flumazenil radiotracers in the raten_AU
dc.typeJournal Articleen_AU
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