6-¹⁸F-Fluorodopamine (¹⁸F-FDA) PET is a highly sensitive tool for the localization of pheochromocytoma (PHEO). The aim of this study was to establish cutoff values for pathologic and physiologic adrenal gland tracer uptake. Methods: ¹⁸F-FDA PET with CT coregistration was performed in 14 patients (10 men and 4 women; age [mean ± SD], 42.9 ± 13.3 y) with unilateral adrenal gland PHEO and in 13 control subjects (5 men and 8 women; age, 51.7612.5 y) without PHEO. Standardized uptake values (SUVs) were compared between adrenal glands with PHEO and normal left adrenal glands in control subjects. Results: ¹⁸F-FDA accumulation was observed in all adrenal glands with PHEO and in 6 of 13 control adrenal glands (P = 0.02). The SUV was higher in adrenal glands with PHEO (mean ± SD, 16.1 ± 6.1) than in ¹⁸F-FDA-positive control adrenal glands (7.7 ± 1.4) (P = 0.005). SUV cutoffs for distinguishing between adrenal glands with PHEO and normal adrenal glands were 7.3 (100% sensitivity) and 10.1 (100% specificity). Conclusion: The SUVs of adrenal foci on ¹⁸F-FDA PET facilitate the distinction between adrenal glands with PHEO and normal adrenal glands.