FIGURE 2. Example of model estimation of blood flow and metabolic rate. (A) Compartmental model fits of tumor and tissue time–activity curves. Lack of smoothness in fit curve (tumor fit and normal [Nl] breast fit) results from lack of smoothing of blood time–activity curve, which serves as input to model, before use in model. (B) Graphic analysis plot for tumor and Nl breast shows line fits for data from 30 to 60 min after injection. Y-axis is normalized activity, which is tissue activity/blood activity. X-axis is normalized time, which is integrated blood activity/blood activity. 18F-FDG flux constant is estimated from slope of line fit (tumor fit and Nl breast fit).
