Images show lung cancer screening CT scan in 66-year-old woman. (a) Axial, (b) coronal, and (c) sagittal images show right upper-lobe nodule (arrow) classified as Lung CT Screening Reporting and Data System (Lung-RADS) category 3 nodule by one reader using manual measurements, as Lung-RADS 4A nodule by two readers using manual measurements, and as Lung-RADS 3 nodule by all three readers using volumetry. Manual average diameter is 7 mm as measured by one reader, 8 mm as measured by one reader, and 9 mm as measured by one reader; semiautomated average diameter is 7 mm as measured by two readers and 8 mm as measured by one reader; and semiautomated volume is 122 mm3 as measured by two readers and 133 mm3 as measured by one reader. Nodule remains stable on surveillance scans through 3 years of follow-up.