Abstract
BACKGROUND: This study evaluates the feasibility of using a simplified Patlak parametric imaging technique with a scaled population-based input function (sPBIF) in pancreatic cancer. METHODS: Twenty-six patients underwent multi-bed, multi-pass [(18)F]FDG PET/CT scans, from which both dynamic and static PET images were reconstructed. Patlak parametric images were generated from the dynamic PET series using both the image-derived input function (IDIF) and the sPBIF. The consistency between IDIF and sPBIF was evaluated by comparing the area under the curve (AUC) and Patlak parameters derived from both input functions. The detectability of pancreatic lesions, assessed by tumor-to-background ratio (TBR) and contrast-to-noise ratio (CNR), was compared between SUV and Patlak parametric images. Additionally, the correlation between clinicopathological features and PET parameters, including SUV and Patlak values, was analyzed. RESULTS: We found good agreement between the AUC for IDIF and sPBIF with correlation coefficients of 0.87 and 0.93 for the 0-30 min and 0-50 min intervals, respectively. The Patlak parameters from IDIF and sPBIF presented correlation coefficients higher than 0.94. The SUV and Patlak K(i) exhibited correlation coefficients greater than 0.92 and 0.73 in malignant and benign pancreatic lesions, respectively. The SUV and Patlak V(0) correlated with correlation coefficients higher than 0.75 in benign lesions, but exhibited only a weak correlation in malignant lesions. The TBR of Patlak K(i) was significantly higher in malignant lesions compared to SUV. However, the CNR of Patlak K(i) was lower due to increased noise in the parametric images. Most clinicopathological features showed weak correlation with PET parameters, except for a marginal classification of lesion differentiation by the maximum K(i) value. CONCLUSIONS: The sPBIF approach enables the acquisition of additional Patlak parametric images alongside static SUV imaging in pancreatic cancer patients. K(i) parametric imaging provided higher contrast than static imaging for detecting pancreatic lesions.