In:
Journal of Cerebral Blood Flow & Metabolism, SAGE Publications, Vol. 30, No. 5 ( 2010-05), p. 994-1007
Kurzfassung:
18 F-Fallypride and 11 C-FLB457 are commonly used PET radioligands for imaging extrastriatal dopamine D 2 /D 3 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 18 F-fallypride and 11 C-FLB457 was made using a MI protocol. Injection protocols were designed to estimate K 1 , k 2 , f ND k on , B max , and k off in the midbrain and cortical regions of the rhesus monkey. 11 C-FLB457 cleared from the arterial plasma faster and yielded a ND space distribution volume ( K 1 / k 2 ) that is three times higher than 18 F-fallypride, primarily due to a slower k 2 (FAL:FLB; k 2 =0.54 min −1 :0.18 min −1 ). The dissociation rate constant, k off , was slower for 11 C-FLB457, resulting in a lower K Dapp than 18 F-fallypride (FAL:FLB; 0.39 nM:0.13 nM). Specific D 2 /D 3 binding could be detected in the cerebellum for 11 C-FLB457 but not 18 F-fallypride. Both radioligands can be used to image extrastriatal D 2 /D 3 receptors, with 11 C-FLB457 providing greater sensitivity to subtle changes in low-receptor-density cortical regions and 18 F-fallypride being more sensitive to endogenous dopamine displacement in medium-to-high-receptor-density regions. In the presence of specific D 2 /D 3 binding in the cerebellum, reference region analysis methods will give a greater bias in BP ND with 11 C-FLB457 than with 18 F-fallypride.
Materialart:
Online-Ressource
ISSN:
0271-678X
,
1559-7016
DOI:
10.1038/jcbfm.2009.270
Sprache:
Englisch
Verlag:
SAGE Publications
Publikationsdatum:
2010
ZDB Id:
2039456-1
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