Schematic representation of different methods to determine the rate constants obtained from one-tissue compartment model. (A) Rate constants K
1 and k
2, obtained from one-tissue compartment model with all scan data incorporated. K
1 represents the passive influx, while k
2 is a combination of active and passive efflux. (B) shows rate constants obtained from a one-tissue compartment model with only the first 2 min of the scan data. Pseudo K
1 is defined as a combination of the passive influx and active efflux, but k
2 only represents passive efflux. C, concentration of 11C-dLop.