7-Fluoro-3,4-dihydro-4-methyl-1H-1,4-benzodiazepine-2,5-dione-d3 is the isotope labelled analog of 7-Fluoro-3,4-dihydro-4-methyl-1H-1,4-benzodiazepine-2,5-dione,. 7-Fluoro-3,4-dihydro-4-methyl-1H-1,4-benzodiazepine-2,5-dione, is used as a reactant in the synthetic preparation of 18F-labeled radiotracers for γ-aminobutyric acid A (GABAA) receptor positron emission tomography (PET) imaging.