RESUMO
Objective To analyze the metabolic differences of 11C-flumazenil (11C-FMZ) with different specific radioactivity by detecting the percentage proportion of the main metabolites in vivo. Methods 5 male and 5 female volunteers with average age of (41.7±4.7) years and weight of (69.3±6.8) kg were selected from May to October 2019. 11C-FMZ with high and low specific radioactivity (268.3±57.2)×103 and (57.8±11.4)×103 Ci/mol was injected successively. The percentage of injected dose/liter of 11C-FMZ and its metabolites in the plasma at 1, 2, 3, 4, 5, 10, 15, 20, 30, 40 and 60 min after the injection was measured. Paired sample mean t test was used to calculate and compare the percentage of metabolites in the two groups. Results The percentage proportion of metabolites increased gradually with time, and reached the stable level after 15 min. The percentage proportion of low specific radioactivity group was higher than that of high specific radioactivity group with a significant statistical difference between 15 min and 60 min (P<0.05). Conclusion The metabolic rate of 11C-FMZ with different specific radioactivity was significantly different after injection and the specific radioactivity difference should be avoided if possible in clinical application.