肺癌是最常见的恶性肿瘤,我国2010年肺癌新发病例达60.59万~([1]),居各类恶性肿瘤之首。多数病例因早期症状不明显,就诊发现时已属中、晚期,5年生存率仅为15.6%~([2])。早期发现、及时处理是改善肺癌预后的关键。对于早期肺癌的诊断近年有很多研究进展,而胸部CT检查是发现早期肺癌的有效方法。早期肺癌的CT影像表现为直径≤30 mm的小结节,甚至 Lung cancer is the most common malignant tumor. In China, the number of new cases of lung cancer in 2010 reached 605900 ~ ([1]), ranking the first among all kinds of malignant tumors. The majority of cases due to early symptoms is not obvious, the treatment was found in the late, 5-year survival rate was only 15.6% ~ ([2]). Early detection and timely treatment is the key to improve the prognosis of lung cancer. In recent years, there have been many advances in the diagnosis of early lung cancer, and chest CT examination is an effective method to detect early stage lung cancer. CT images of early stage lung cancer show small nodules of ≤30 mm in diameter or even