The effect of respiratory-gated positron emission tomography/computed tomography in patients with pancreatic cancer.

Our aim of this study was to evaluate prospectively in patients with pancreatic cancer the effects of respiratory- gating during PET/CT acquisition on the determination of lesion volume and to measure tracer uptake. Our research included 36 patients diagnosed with pancreatic cancer. They underwent conventional whole-body PET/CT and subsequently respiratory-gated PET/CT of the upper abdomen. Based on list-mode PET acquisition data, respiratory-gated and non-gated images were created. Maximum standardized uptake values (SUVmax) and lesion volumes were compared between gated and non-gated images and also the rate of increase in SUVmax based on lesion size. Results showed that respiratory gating was successful in 34/36 patients. The median non-gated SUVmax was 6.2±2.1 and was 8.1±2.5 for respiratory- gated (P<0.01). Lesion volumes could be calculated in 27/34 patients. The median non-gated lesion volume was 5.82±5.57cm(3) and 4.31±4.56cm(3) for respiratory-gated (P<0.01). Furthermore, small lesions of ≤2cm had a significantly higher proportion of increased SUVmax compared to large lesions of >2cm (P=0.016). In conclusion, respiratory-gated PET/CT for patients with pancreatic cancer reduced respiratory motion artifacts and allowed significantly higher SUVmax to be obtained. In addition, the rate of increase in SUVmax tended to be higher in patients with pancreatic cancers of less or equal to 2cm diameter.