Abstract: It is very difficult to differentiate correctly between the benign and malignant solitary pulmonary nodules(SPNs). About 30% of the resected indefinite SPNs are benign. Conventional imaging techniques can identify most patients with SPN, but cannot afford a few patients with SPN which have equivocate manifestations, and each has some limitations. PET-CT is a new imaging technique that can offer metabolic and anatomical information of SPN, which results in higher diagnostic sensitivity and accuracy of SPN. Recently various new imaging method is further improved the diagnostic accuracy.