Linearized method: A new approach for kinetic analysis of central dopamine D2 receptor specific binding

We proposed a new method (`linearized method´) to analyze neuroleptic ligand-receptor specific binding in a human brain using positron emission tomography (PET). We derived the linear equation to solve four rate constants, k₃, k₄, k₅, k₆ from PET data. This method does not demand a radioactivity curve in plasma as an input function to the brain, and can perform fast calculations in order to determine rate constants. We also tested the nonlinearized method including nonlinear equations which is a conventional analysis using plasma radioactivity corrected for ligand metabolites as an input function. We applied these methods to evaluate dopamine D₂ receptor specific binding of [¹¹C] YM-09151-2. The value of B_max/K_d=k₃/k ₄ obtained by the linearized method was 5.72±3.1 which was consistent with the value of 5.78±3.4 obtained by the nonlinearized method