Diagnostic accuracy of dual-phase 18F-FDG PET/CT using time-of-flight reconstruction algorithm in conjunction with TrueX or Q.Clear in staging suspected pancreatic cancer

Demarcation of small pancreatic and metastatic abdominal lesions is challenging due to the noisy background. We evaluated the impact of time-of-flight (TOF) in conjunction with TrueX (= point spread function (PSF)-based algorithm) or Q.Clear (= Bayesian penalized likelihood reconstruction algorithm) in dual-phase (DP) ¹⁸F-FDG-PET/CT on image quality (IQ) and lesion detection rate in staging suspected pancreatic cancer. This prospective single-center study included 120 patients. A total of 908 lesions were evaluated by three board-certified nuclear medicine physicians. IQ, SUV_max, and lesion volume (V) of pancreatic lesions, lymph node metastases, organ metastases, and other benign lesions were compared between TOF and non-TOF. All pancreatic lesions were histopathologically confirmed, and all other lesions were confirmed either histopathologically or radiologically. IQ and lesion demarcation were scored on a 6-point Likert-type scale. Overall IQ and demarcation of pancreatic lesions (PLD) were very good in TOF-images (overall IQ, non-TOF, 2.2; TOF, 1.8, P = 0.017; PLD, non-TOF, 2.6, TOF, 2.2, P < 0.001). Thirty-four additional lesions in 23 (19%) patients were detected using TOF alone (mean [SD] SUV_max 4.6 [1.5]; mean [SD] V 2.6 cm³ [1.3]). 18/23 metastatic lesions identified with TOF alone led to treatment change in 8 patients. SUV_max was significantly increased (P< 0.001), whereas V was significantly decreased in TOF images (P = 0.002). Application of TOF poses additional value in detecting small pancreatic and metastatic lesions, which has an impact on further treatment, avoiding unnecessary surgery.