Measurement of Cortical Dopamine D1 Receptor Binding with [11C]SCH 23390: A Test–Retest Analysis

Abstract

[¹¹C]SCH 23390 is a standard ligand for positron emission tomography (PET) studies on striatal dopamine D₁ receptors. Its usefulness for cortical D₁ receptor quantification in human PET studies has been questioned but has not been addressed previously. The authors tested the reproducibility of [¹¹C]SCH 23390 binding potential (BP) in cortical areas in five healthy volunteers using three-dimensional PET. Measurement of D₁ receptor BP was reproducible in basal ganglia, as well as in all cortical areas studied (intraclass correlation coefficients between 0.81 and 0.92). The absolute variability in cortical areas was 9.21% ± 0.07%. The reproducibility of cortical D₁ receptor BP measurement with [¹¹C]SCH 23390 is equal to that observed with a more recent D₁ -ligand, [¹¹C]NNC 112. [¹¹C]NNC 112 produces slightly higher specific-to-nonspecific binding ratios but has markedly slower kinetics resulting in a need for a longer scan time. These aspects should be considered when designing studies on the cortical D₁ -like receptors.