Before revision: For a catenary two-tissue compartment model with transfer constants (forward transport from plasma to tissue), ( backward transport from plasma to tissue ), (binding parameter proportional to ), and (dissociation constant) to analyze enzyme or receptor system, the slope represents the total distribution volume () and is given by , where , , , and , in which is the concentration of radiotracer binding sites, is the equilibrium dissociation constant for the binding site complex, is the ligand-receptor association constant, is the ligand-receptor dissociation constant.
After revision: For a catenary two-tissue compartment model with transfer constants (forward transport from plasma to tissue), ( reverse transport from tissue to plasma ), (binding parameter proportional to ), and (dissociation constant) to analyze enzyme or receptor system, the slope represents the total distribution volume () and is given by , where , , , and , in which is the concentration of ligand ligand-binding sites, is the equilibrium dissociation constant for the binding site complex, is the ligand-binding association constant, is the ligand-binding dissociation constant.