Determination of optimal acquisition time of [¹⁸F]FCWAY PET for imaging serotonin 1A receptors in the healthy male subjects

The purpose of this research is to find optimal acquisition time point of [¹⁸F]FCWAY PET for the assessment of serotonin 1A receptor (5-HT_1A) density. To achieve this goal, we examined the specific-to-nonspecific ratios in various brain regions. The cerebellum has very few 5-HT_1A receptors in the brain, so we set this region as the reference tissue. As a result, specific-to-nonspecific binding ratios in the frontal, temporal cortex and the hippocampus were steadily increased at 90min after injection and remained stable at 120min. In addition, the binding ratio of the late time was significantly higher than that of the previous time points. From these results, we recommend that 90min p.i. is a better single time point for the analysis rather than previous time points for assessing [¹⁸F]FCWAY binding to 5-HT_1A receptors.