Indirect and Direct Pharmacokinetic Parameter Reconstruction in Dynamic Diffuse Fluorescence Tomography by Adaptive Extended Kalman Filtering Scheme

Pharmacokinetic diffuse fluorescence tomography (DFT) can provide helpful diagnostic information for tumor differentiation and monitoring. Among the methods of achieving pharmacokinetic parameters, adaptive extended Kalman filtering (AEKF) as a nonlinear filter method demonstrates the merits of quantitativeness, noise-robustness, and initialization independence. In this paper, indirect and direct AEKF schemes based on a commonly used two-compartment model were studied to extract pharmacokinetic parameters from simulation data. To assess the effect of metabolic rate on the reconstruction results, a series of numerical simulation experiments with the metabolic time range from 4.16 min to 38 min were carried out and the results obtained by the two schemes were compared. The results demonstrate that when the metabolic time is longer than 18 min, the pharmacokinetic-rate estimates of two schemes are similar; however, when the metabolic time is shorter than 5 min, the pharmacokinetic parameters obtained by the indirect scheme are far from the true value and even unavailable.