PET radiotracer Chemical name and structure Application in ALS References [11 C]flumazenil Ethyl 8-fluoro-5-(methyl-11 C)-6-oxo-5,6-dihydro-4H-benzo[f]imidazo[1,5-a][1,4]diazepine-3-carboxylate Decreased binding in mainly motor and frontal regions as compared to controls. [6 , 65 , 66 ] [11 C]WAY100635 N-(2-(4-(2-(methoxy-11 C)phenyl)piperazin-1-yl)ethyl)-N-(pyridin-2-yl)cyclohexanecarboxamide Decreased binding in several gyri and frontotemporal regions through SPM and VOI analysis as compared to controls. [67 ] [18 F]FPEB 3-(Fluoro-18 F)-5-(pyridin-2-ylethynyl)benzonitrile Increased binding in the hippocampus, striatum, and frontal cortex of mice models. [49 ] [18 F]PSS232 (E)-3-(pyridin-2-ylethynyl)cyclohex-2-en-1-one O-(3-(2-(fluoro-18 F)ethoxy)propyl) oxime Increased binding in the striatum, hippocampus, and cortex in mice models and increased binding in the basal ganglia and frontal, motor, and temporal cortices of ALS postmortem tissue. [48 ] [18 F]fallypride N-((1-allylpyrrolidin-2-yl)methyl)-5-(3-(fluoro-18 F)propyl)-2,3-dimethoxybenzamide Reduced uptake in the superior frontal gyrus, nucleus accumbens, left temporal lobe, and angular gyrus in patients compared to controls. [68 ] [18 F]SynVesT-1 (R)-4-(3-(fluoro-18 F)phenyl)-1-((3-methylpyridin-4-yl)methyl)pyrrolidin-2-one Decreased binding in the frontal lobe, anterior cingulate, hippocampus-insula region, and right temporal lobe in patients compared with controls. [69 ] [18 F]OF-NB1 3-(4-(2-(Fluoro-18 F)phenyl)butyl)-2,3,4,5-tetrahydro-1H-benzo[d]azepine-1,7-diol Decreased binding in postmortem frontal and motor cortex brain tissue compared to control tissue. [70 ]
