For the comparison of the usage of the other time points, we investigated the usage of brain concentration in earlier: 15 min or later: 2 h time points as input instead of 1 h. The overall RMSE and R2-values were 0.312 and 0.760 when using 15 min (N= 407), and 0.300 and 0.751 (N=306) when using 2 hr. Although the result when using 1 hr was best (overall RMSE and R2values: 0.246 and 0.805) in this study, since the difference was not large, we can decide what time point is the best according to each cases practically.