Fig. 4

ΔAIC for organs and metastatic lesions. ΔAIC = AIC (reversible two-tissue compartment model)—AIC (irreversible two-tissue compartment model). As the model with the lowest AIC is the best fit, a positive ΔAIC reflects that the irreversible two-tissue compartment model is the best fit, while a negative ΔAIC reflects that the reversible two-tissue compartment model is the best fit. Black triangles have ΔAIC ≤ 2 while black dots have ΔAIC > 2 (ΔAIC > 2 is considered a significant difference between models)