A novel relative-equilibrium graphical plot for rapid reversible tracer studies in dynamic PET imaging

Abstract Objective: This study aims to address the issue of long scan durations required by traditional graphical analysis methods, such as the Logan plot and its variant, the reversible equilibrium (RE) Logan plot, for dynamic PET imaging of tracer kinetics. 
Approach: We propose a relative RE Logan model that builds on the principles of the Logan plot and its variant to significantly reduce scan time without compromising the accuracy of tracer kinetics analysis. The model is supported by theoretical evidence and experimental validations, including two computer simulations and one clinical data analysis. 
Main results: The proposed model demonstrates a significant linear relationship between the variable x and the slope DV_T of the RE Logan plot, and the variable x' and the slope DV_T' of the relative RE Logan plot. The Pearson correlation coefficients (r) of the linear fitting of the x' to the x equal 0.9849 in the simulated data and 0.9912 in the clinical data. Similarly, the r value for the linear fitting of DV_T' to DV_T equal 0.9989 and 0.9988 in the simulated data, and 0.9954 in the clinical data. 
Significance: These results demonstrate the model’s capability to maintain strong linear relationships and produce parametric images comparable to those of the traditional RE Logan plot, but with the considerable advantage of shorter scan durations. This innovation holds significant potential for enhancing the efficiency and feasibility of PET imaging in clinical settings.