The PKIN tool allows the simultaneous fitting of the shape parameters of the blood models and the kinetic parameters of the tissue model. This fitting mode can be activated by checking the Float blood parameters box on the Extras pane. It is active in the fitting of the single tissue TAC as well as in coupled fitting.
With Fit blood on, ALL parameters of the Whole blood and the Plasma model (but not the plasma fraction or parent fraction parameters) which have the fit check on will be modified during the fit of the kinetic tissue model. In the situation illustrated below 9 parameters (plus additional on the Whole blood panel) will be fitted at the same time.
Note: Only the tissue model curve is fitted to the measurement. The blood models are not fitted to the actual blood measurements. It is only the impact of the blood curves on the calculated tissue model curve which results in the modification of the blood model parameters.