Pre-Hydration and a Forced Diuresis Protocol for 18F-FDG PET/CT Yielded an Optimal Effect on Primary Pelvic Malignancies

<b>Background:</b> Positron emission tomography (PET) with ¹⁸F-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. <b>Methods:</b> We reviewed 109 patients with PTs who had undergone ¹⁸F-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. <b>Results:</b> 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. <b>Conclusions:</b> 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.