Investigation of Radioactivity Concentration of the Normal Brain Region for the Phantom Experiment in Brain Tumor PET Imaging

PURPOSE: There are few reports focusing on the radioactivity concentration in the normal brain region for the phantom experiment. We investigated the radioactivity concentration of normal brain regions for the phantom experiment of brain tumor PET imaging. METHODS: A total of 30 patients (age: 53±19 years old, body weight: 58±11 kg) underwent the brain tumor PET examinations using 18F-fluorothymidine (18F-FLT), 18F-fluoromisonidazole (18F-FMISO) and 11C-methionine (11C-MET) during April 1, 2017-October 1, 2017. A region of interest was set in the brain parenchyma excluding the tumor lesion area and the ventricle in PET image, and radioactivity concentrations of the normal brain region were obtained. RESULTS: The radioactivity concentrations of the normal brain region were 0.79±0.25 kBq/ml for 18F-FLT, 2.34±0.42 kBq/ml for 18F-FMISO and 4.05±0.80 kBq/ml for 11C-MET. CONCLUSION: We proposed the radioactivity concentrations of background region in the phantom for brain tumor PET imaging using 18F-FLT, 18F-FMISO and 11C-MET.