[Thiocarbonyl-11C]disulfiram ([11C]DSF) was synthesized via iodine oxidation of [11C]diethylcarbamodithioic acid ([11C]DETC), which was prepared from [11C]carbon disulfide and diethylamine. The decay-corrected isolated radiochemical yield (RCY) of [11C]DSF was greatly affected by the addition of unlabeled carbon disulfide. In the presence of carbon disulfide, the RCY was increased up to 22% with low molar activity (Am, 0.27 GBq/μmol). On the other hand, [11C]DSF was obtained in 0.4% RCY with a high Am value (95 GBq/μmol) in the absence of carbon disulfide. The radiochemical purity of [11C]DSF was always >98%. The first PET study on [11C]DSF was performed in mice. A high uptake of radioactivity was observed in the liver, kidneys, and gallbladder. The uptake level and distribution pattern in mice were not significantly affected by the Am value of the [11C]DSF sample used. In vivo metabolite analysis showed the rapid decomposition of [11C]DSF in mouse plasma.