Abstract: For qualitation diagnosis of single pulmonary nodules (SPN), both ¹⁸F-fluorodeoxyglueose (¹⁸F-FDG)PET and ¹¹C-choline PET have their own advantages. The outcome of the PET imaging will have more value for diagnosis if the two agents are used. ¹⁸F-FDG PET has more high sensitivity and specificity for diagnosis of malignant SPN and metastasis of lymphonodes, ¹¹C-choline PET can decrease the false positive rate of inflamed foei and is helpful to diagnosis of brain metastasis from the malignant SPN. However, both agents can't be accumulated in bronehioalveolar carcinoma and small lung cancer with lower metabolism. It is reported that 3'-deoxy-3'-¹⁸F-fluorothymidine (¹⁸F-FLT) PET can be used to detect the benign nodes from the malignanee, evaluate the therapeutic effect and prognosis.¹⁸F-FLT may be a prospective PET tracer in clinical applieation.