The role of 11C-acetate PET imaging for diagnosis of renal cancer

Objective: To evaluate the relationship between 11C-acetate and 18F-fluorodeoxyglucose (FDG) for the detection of renal neoplasm and to determine the feasibility of 11C-acetate used as a complement of 18F-FDG. Methods: Twenty-nine patients with 25 primary lesions underwent 11C-acetate (111-655 MBq intravenous injection) PET imaging (early imaging after injection instantly, and delayed imaging 10 min latter), and among them 22 patients underwent 18F-FDG PET imaging within one week. Twenty-five primary and three metastatic lesions were confirmed histologically. One metastasis was proved by CT and clinical follow-up. Thirteen renal clear cell carcinoma and six transitional cell carcinoma lesions had pathologic grading. Results: Among all human organs, pancreas showed persistent highest uptake of 11C-acetate. Activity in bowel was due to the pancreatic excretion. High accumulation was also observed in renal cortex initially but was cleared rapidly, while most primary lesions of renal cell carcinoma showed radioactive hot areas in delayed images. Compared with 18F-FDG (30.8% positively), 11C-acetate was more sensitive in detecting primary lesions of renal cell carcinoma (76.9% positively). However, 18F-FDG was an effective tracer in the diagnosis of transitional cell carcinoma, since 5 (5/5) of them were all visualized while only 2 (2/6) were demonstrated in 11C-acetate imaging. One renal angiomyolipoma was both positive in early and delayed imaging of 11C-acetate, but urethritis was negative. Conclusions: 11C-acetate is more sensitive than 18F-FDG for the detection of well differentiated renal cell carcinoma, especially for grade I - Il. Therefore, 1lC-acetate imaging can be used as a complement for 18F-FDG. (authors)