Differential Diagnosis of Solitary Pulmonary Nodules with Positron Emission Tomography Using [11C]L-Methionine

Abstract
Two patient with soliatray pulmonary nodules, 1.5-2.0 cm in diameter, were studied by positron emission tomography using [11C-Methyl]L-methionine (11C-Met). Case 1 showed high accumulation of 11C-Met in the tumor, and a tumor/muscle ratio of 6.0 suggesting malignancy. Tissue obtained by biopsy revealed a squamous cell carcinoma. Case 2 showed nonspecific isotope accumulation in the tumor, and a tumor/muscle ratio of 1.2 suggesting a benign lesion. Lung biopsy demonstrated granuloma. Positron emission tomography with 11C-Met seems to be useful for the differential diagnosis of solitary lung nodules.