Figure 1b: Digital tomosynthesis of human lung. (a) Posteroanterior radiograph shows region of interest. (b) Digital tomosynthesis section demonstrates 15-mm pulmonary nodule (arrow) that was not visualized in a. Note also improved clarity of vascular detail in b, which was reconstructed with a matrix inversion tomosynthesis technique that used 61 projection images acquired in 10 seconds over a total tube swing angle of 16°. Fifty-nine sections were generated with 3-mm spacing. Total subject entrance exposure was approximately the same as that for a screen-film lateral chest radiograph. (Image courtesy of James T. Dobbins III, PhD, H. Page McAdams, MD, and Devon J. Godfrey, Duke University Medical Center.)