The role of positron emission tomography in the detection of pancreatic disease.

Positron emission tomography (PET) was used to assess possible pancreatic disease in 100 patients. Following injection of 10-15 mCi (370-740 MBq) of 11C-L-methionine, 4-12 transverse sections 2 cm thick were obtained. In 85 patients with a definite diagnosis (45 normal, 9 acute pancreatitis, 18 chronic pancreatitis, and 13 cancer), PET showed a sensitivity of 85.0%, a specificity of 97.8%, and an accuracy of 91.8%, higher than with transmission computed tomography (CT) or ultrasonography, despite relatively low spatial resolution; this can be explained by the fact that exocrine pancreatic function was altered prior to morphological change. In 22 normal subjects, 0.011 +/- 0.003% (mean +/- S.D). of injected 11C was found in 1 ml of liver tissue and 0.015 +/- 0.005% in 1 ml of pancreatic tissue; the pancreas-to-liver concentration ratio was 1.3 +/- 0.4. Hepatic 11C concentration was identical in the four groups of patients. Pancreatic uptake of 11C-L-methionine was significantly lower in patients with chronic pancreatitis (n = 13) and pancreatic carcinoma (n = 10) (p less than 0.001); however, it was not possible to distinguish cancer from chronic pancreatitis because the same functional alteration occurred in both.