[C-11]methionine positron emission tomography for the evaluation of pancreatic exocrine function in chronic pancreatitis

Positron emission tomography (PET) can be used for the quantitative analysi s of amino acid metabolism. The aim of this study was to investigate whethe r pancreatic exocrine function can be evaluated by [C-11]methionine PET in chronic pancreatitis (CP) patients. Dynamic PET scan of the pancreas and li ver was performed in eight healthy subjects and seven patients with CP afte r intravenous (i.v.) injection of [C-11]methionine. Simultaneously, duodena l juice was collected with the background of continuous i.v, administration of secretin (125 ng/kg/h). The radioactivity ratio of the pancreas to that of the liver (PLR) was calculated by regions of interest (ROI) analysis. A mylase output and bicarbonate concentration were measured in the duodenal a spirates. The PLR of CP patients was significantly lower than that of healt hy subjects at all time points after methionine injection. The PLRs at 4.5 minutes (PLR4.5) after methionine injection were positively correlated with the amylase output, mean bicarbonate concentration, and volume of duodenal aspirates (R = 0.74, 0.69, 0.46). It is concluded that [C-11]methionine PE T would be a noninvasive method for the evaluation of exocrine pancreatic f unction, which may represent total amino acids uptake of viable acinar cell s in the pancreas.