Is Dynamic Total-body PET Imaging Feasible in the Clinical Daily Practice?

Abstract PurposeDynamic PET (dPET) imaging of multi-temporal frames can quantitate tracer kinetics and has been mostly used in the research rather than clinical daily practice due to the long acquisition time. The total-body PET/CT scanner can generate fine time-activity curves (TACs) in dPET imaging and provide tempo-spatially synchronized pharmacokinetics in the entire human body. To investigate the feasibility in daily practice, the study aimed to explore the shortest acquisition time of dPET imaging. MethodsTen patients who underwent an 18F-FDG total-body dPET examination were retrospectively enrolled. Both the Patlak graphic analysis (Ki) and irreversible two tissues compartment model (i2TCM) analysis (K1, k2, k3) were used to calculate the kinetic parameters with different shortened acquisition durations. These kinetic parameters at various organs/tissues and lesions were compared with those obtained from the reference 60min acquisition. In addition, a hybrid approach combining the initial 20-min dPET data and the static PET scan at 55-60 min post-injection was proposed, and the kinetic parameters were calculated and compared with the references. ResultsPatlak Ki derived from the first 50-min dPET acquisition showed no significant difference in healthy organs/tissues compared with the reference (all p > 0.05), while the lesions can be visually distinguished even in the initial 20-min Ki images. In the i2TCM analysis, the kinetic parameters — K1, k2, k3 of 30-min dPET acquisition showed no significant difference for healthy organs/tissues and lesions compared to 60-min dPET acquisition (all p > 0.05). The kinetic parameters obtained from the proposed hybrid approach can provide reliable kinetic parameters as well as those obtained in the static PET imaging. ConclusionsThe dPET total-body imaging can be shortened to 30 min to generate reliable kinetic parameters with i2TCM. Additionally, the hybrid approach provides both robust tracer metabolic information and the conventional standard uptake values (SUVs), demonstrating its feasibility in clinical practice.