 Figure 3a: (a) Transverse 5-mm CT section shows an apparently pure ground-glass nodule in the left lower lobe (arrow). (b) Transverse 1-mm CT section at the same level as a reveals that this is a suspicious part-solid nodule with cystic components (arrow).  Figure 3b: (a) Transverse 5-mm CT section shows an apparently pure ground-glass nodule in the left lower lobe (arrow). (b) Transverse 1-mm CT section at the same level as a reveals that this is a suspicious part-solid nodule with cystic components (arrow).  Figure 4a: (a) Transverse 1-mm CT section shows a nodular opacity adjacent to the minor fissure (arrow). (b) Coronal reconstructed CT image shows that the opacity is a benign linear scar or lymphoid tissue (arrow).  Figure 4b: (a) Transverse 1-mm CT section shows a nodular opacity adjacent to the minor fissure (arrow). (b) Coronal reconstructed CT image shows that the opacity is a benign linear scar or lymphoid tissue (arrow). CT examinations of the thorax performed to follow lung nodules should use a low-radiation technique (grade 1A: strong recommendation, high quality evidence). Techniques to reduce radiation dose are of particular importance, given the frequency with which follow-up CT examinations are performed. We recommend adjusting exposure factors according to body habitus, with a goal of achieving a volumetric CT dose index (or CTDI |