Automatic input function estimation for pharmacokinetic modeling

This system (200), apparatus (300), and method (100) of the present invention provide an analytic way to solve the (input) estimation problem of pharmacokinetic modeling: estimating parameters of a kinetic model from a series of tracer (radioactively labeled imaging agent) activity measurements (e.g. by positron emission tomography). Since the model describes a biological process its parameters have a direct functional interpretation (e.g. hypoxia for the tracer FMISO) that can be of diagnostic value. The measurements represent the activity distribution in time and space in the form of a 4D data set d(t, x, y, z), t = 1, . . . , T. The kinetic parameter estimation procedure (205) requires knowledge of the tracer input activity. This input activity can either be measured invasively or it can be estimated from the data in a preprocessing step.; The estimation problem can be solved efficiently if the model and its input are described analytically. Typically parameterized functions (often sums of exponential term