Figure 4: The error in the estimated PET kinetic parameters as a function of the noise in the tissue curves. Each panel corresponds to a different set of PET kinetic parameters. For each set of parameters, when the error in is less than 10 times the square root of the activity level, the parameter error is less than 50. As the error in continues to increase, the error in and increases rapidly. The error in and also continues to increase, but less rapidly.