A partial saturation protocol permits the non-invasive and time-efficient estimation of B and appK separately. Given the different biological phenomena that underlie these parameters, this method may be applied for the in-depth study of the dopaminergic system in translational molecular imaging studies. It can detect the biological variations in these parameters, dissociating the variations in receptor density (B) from affinity (1/appK), which reflects the interactions of the receptor with its endogenous ligand.