• Medientyp: E-Artikel
  • Titel: High-Affinity Dopamine D2/D3 PET Radioligands 18F-Fallypride and 11C-FLB457: A Comparison of Kinetics in Extrastriatal Regions Using a Multiple-Injection Protocol
  • Beteiligte: Vandehey, Nicholas T; Moirano, Jeffrey M; Converse, Alexander K; Holden, James E; Mukherjee, Jogesh; Murali, Dhanabalan; Nickles, R Jerry; Davidson, Richard J; Schneider, Mary L; Christian, Bradley T
  • Erschienen: SAGE Publications, 2010
  • Erschienen in: Journal of Cerebral Blood Flow & Metabolism, 30 (2010) 5, Seite 994-1007
  • Sprache: Englisch
  • DOI: 10.1038/jcbfm.2009.270
  • ISSN: 0271-678X; 1559-7016
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  • Beschreibung: 18F-Fallypride and 11C-FLB457 are commonly used PET radioligands for imaging extrastriatal dopamine D2/D3 receptors, but differences in their in vivo kinetics may affect the sensitivity for measuring subtle changes in receptor binding. Focusing on regions of low binding, a direct comparison of the kinetics of 18F-fallypride and 11C-FLB457 was made using a MI protocol. Injection protocols were designed to estimate K1, k2, fND kon, Bmax, and koff in the midbrain and cortical regions of the rhesus monkey. 11C-FLB457 cleared from the arterial plasma faster and yielded a ND space distribution volume ( K1/ k2) that is three times higher than 18F-fallypride, primarily due to a slower k2 (FAL:FLB; k2=0.54 min−1:0.18 min−1). The dissociation rate constant, koff, was slower for 11C-FLB457, resulting in a lower KDapp than 18F-fallypride (FAL:FLB; 0.39 nM:0.13 nM). Specific D2/D3 binding could be detected in the cerebellum for 11C-FLB457 but not 18F-fallypride. Both radioligands can be used to image extrastriatal D2/D3 receptors, with 11C-FLB457 providing greater sensitivity to subtle changes in low-receptor-density cortical regions and 18F-fallypride being more sensitive to endogenous dopamine displacement in medium-to-high-receptor-density regions. In the presence of specific D2/D3 binding in the cerebellum, reference region analysis methods will give a greater bias in BPND with 11C-FLB457 than with 18F-fallypride.
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