In order to evaluate the utility of positron emission tomography (PET) with 18F-labelled deoxyglucose (FDG) for detection of pancreatic cancer 15 patients with pancreatic masses shown by computed tomography were investigated. Static PET scans covering an axial field of view of 15 cm were obtained 45 min after intravenous injection of 150-300 MBq FDG. Focally increased FDG accumulation was present in 12 out of 13 patients with histologically proven adenocarcinoma, in particular in eight of nine lymph node and four of five liver metastases. Scans of two patients with chronic pancreatitis confirmed by surgery revealed a normal FDG distribution. Contrast between tumour and normal tissue depended the metabolic situation prior to FDG injection. High ratios were found in fasting patients whereas no elevated FDG uptake was measured in an insulin-dependent diabetic suffering from carcinoma of the pancreatic head. We conclude that FDG PET might have the potential for detection and even differentiation of pancreatic carcinoma from chronic pancreatitis. Further studies are necessary to substantiate these preliminary findings and to optimize results in diabetic patients.