Some malignant lung neoplasms may demonstrate low or absent uptake on F18-fluorodeoxyglucose (FDG) PET/computed tomography. Pathologic type and clinical stage are independent factors associated with FDG avidity. Among lung malignancies with low FDG avidity, adenocarcinoma in situ and carcinoid are the most common. Early stage disease often has low FDG uptake. Small lesion size is another significant factor associated with negative FDG PET findings, which is due to a partial volume effect. Morphology of lung lesions on anatomic images may also affect FDG avidity. Subsolid pulmonary nodules, ground-glass nodules, or ground-glass opacity may be sources of false-negative PET.