RT Journal Article SR Electronic T1 Evaluation of the Biodistribution of 11C-Methionine in Children and Young Adults JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1902 OP 1908 DO 10.2967/jnumed.112.118125 VO 54 IS 11 A1 Sebastian M. Harris A1 James C. Davis A1 Scott E. Snyder A1 Elizabeth R. Butch A1 Amy L. Vāvere A1 Mehmet Kocak A1 Barry L. Shulkin YR 2013 UL http://jnm.snmjournals.org/content/54/11/1902.abstract AB The purpose of this study was to evaluate the biodistribution of 11C-labeled methionine in non–tumor-involved organs in pediatric patients studied for malignant diseases. Methods: Ninety-three children and young adults with known or suspected malignancies underwent 11C-methionine PET and CT scans. Imaging began 5–15 min after injection of 740 MBq (20 mCi) per 1.7 m2 of body surface area. Images were acquired from the top of the head through the mid thighs. Standardized uptake values were determined using regions of interest drawn on the CT image and transferred to the corresponding transverse PET slice. Results: The highest concentrations of 11C-methionine were found in the pancreas and liver. Less intense uptake was seen in other regions, such as the salivary glands, tonsils, and bone marrow. There was little uptake in the lungs, fat (including brown adipose tissue), and muscle. Uptake in bone marrow, parotid glands, and tonsils was slightly but statistically significantly higher in men than women. Testicular, bone marrow, and left ventricular uptake increased with age. There was little variability statistically between comparisons of uptake change and groupings of age, race, sex, and patients studied at the time of diagnosis versus previously treated patients. Conclusion: High uptake of 11C-methionine is reliably found in the pancreas and liver, consistent with the anabolic functions of these organs. Low uptake in the brain, neck, chest, pelvis, and extremities will facilitate tumor localization in those areas. However, intense uptake in the upper abdomen may limit the diagnostic utility of 11C-methionine in that area.