Abstract
1144
Objectives: Norepinephrine transporter (NET) is considered to play important roles in both physiological and pathological processes in the brain. Although in vivo imaging of the regional brain distribution of NET has been an important research topic during the past years, the measurement of regional NET levels has been hampered by the lack of suitable PET radioligands for NET. (S,S)-[18F]FMeNER-D2 is a recently developed PET ligand for in vivo quantification of norepinephrine transporter. A monkey occupancy study with the radioligand indicated that (S,S)-[18F]FMeNER-D2 can be useful for quantitative PET analysis. In this preliminary study, regional distributions in the living human brain were evaluated. Methods: Brain PET measurements were performed for a total of 255 min after the injection of 188.3 ± 5.7 MBq of (S,S)-[18F]FMeNER-D2 in 4 healthy male subjects. To calculate the percentage of injected (S,S)-[18F]FMeNER-D2 in the brain, regions-of-interest (ROI’s) for whole brain were drawn on the coregistered MRI/PET images. To obtain regional distribution values, ROI’s for the thalamus and caudate were drawn manually on the co-registered MRI/PET images. The uptake ratios (the thalamus versus the caudate) were summed from 90 minutes to 255 minutes. Results: (S,S)-[18F]FMeNER-D2 displayed good brain penetration and selective retention in regions rich in norepinephrine reuptake sites. Mean peak uptake of the injected radiation dose in the whole brain as a percentage of the injected dose was 2.6 ± 0.5% at 12.5 minutes. The radioactivity of the thalamus minus the caudate reached the peak within the PET measurements. The ratio of radioactivity uptake in the thalamus to that in the caudate was 1.50 ± 0.06. Conclusions: The present preliminary investigation indicates that (S,S)-[18F]FMeNER-D2 has suitable characteristics for probing the norepinephrine reuptake system with PET in the human brain.
- Society of Nuclear Medicine, Inc.