Normal Uptake of 11C-Acetate in Pancreas, Liver, Spleen, and Suprarenal Gland in PET

PURPOSE 11C-Acetate is radiotracer being considered an alternative to 18F-fluorodeoxyglucose. Evaluation of 11C-acetate biodistribution in human parenchymal organs is described. METHODS AND MATERIALS 60 consecutive patients referred to 11C-acetate PET CT suspected of renal or prostate cancer relapse with negative results (no recurrent tumor) were included in the study. Acquisition from the base of skull to upper thigh was made 20 min after i.v. injection of 720 MBq of 11C-acetate. The distribution was evaluated by measuring the uptake in pancreas (uncinate process and body separately), liver, spleen, and left suprarenal gland. Clinical data of included patients showed no abnormalities in these organs. RESULTS Biodistributions of 11C-acetate radiotracer were compared in different organs. Standardized uptake values of 11C-acetate were significantly higher in pancreatic parenchyma (SUV mean 6,4) than in liver (SUV mean 3,3), spleen (SUV mean 4,5), or suprarenal gland (SUV mean 2,7) tissues. No significant difference was found between pancreatic head (SUV mean 6,4) and body (SUV mean 5,9) uptake. In case of all aforementioned organs, there were no differences either between both sexes or between formerly diagnosed tumors (renal and prostate). CONCLUSIONS Evaluation of 11C-acetate uptake differences in parenchymal organs will allow establishing normal patterns of distribution. High pancreatic uptake may be used in quantitative assessment of organ function in diffuse nonneoplastic pathology.