Abstract
Background: Positron emission tomography (PET) with (18)F-FDG is being used more frequently to evaluate primary pelvic tumors (PTs). However, a standardized hydration protocol is essential for an optimal diuretic effect and constant results. Methods: We reviewed 109 patients with PTs who had undergone (18)F-FDG PET/CT examinations between November 2006 and April 2013. Four different protocols were used: (a) no hydration (group 1); (b) oral hydration (800 mL) after an early scan (group 2); (c) intravenous (IV) hydration (500 mL) during an early scan followed by oral hydration (800 mL) and IV furosemide (20 mg) after an early scan (group 3); and (d) oral hydration (800 mL) before an FDG injection followed by the protocol from group 3 (group 4). The maximum standardized uptake (SUV(max)) of the urinary bladder (UB) and PTs and the PT/UB SUV(max) ratios were examined. Results: The UB SUV(max) of group 4 was significantly lower in the early scan compared to that in the other three groups. Group 4 had a significantly higher PT/UB SUV(max) ratio in the early scan than the other three groups, and it also had a 52.5% positivity rate for PTs. Conclusions: The pre-hydration plus forced diuresis protocol yielded the optimal effect of UB radiotracer washout and had the best PT/UB SUV(max) ratio in both scans.