Figure 7b. Transverse CT images in a 53-year-old woman with adenocarcinoma of the right upper lobe who was not a candidate for surgery because of comorbid disease. Three-dimensional conformal radiation therapy was performed. (a) Baseline image shows a lobulated lesion (arrows) of the right upper lobe. (b) Image obtained 37 months after completion of radiation therapy shows an atypical pattern of radiation fibrosis of a small nodule (arrow) associated with a linear scar. Without prior knowledge of treatment, this could be misinterpreted as a pulmonary nodule arising from a scar.