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. Author manuscript; available in PMC: 2013 Jul 1.
Published in final edited form as: Phys Med Biol. 2010 Jan 7;55(1):305–327. doi: 10.1088/0031-9155/55/1/018

Figure 2. 4D Landmark point trajectories.

Figure 2

4D landmark point sets were utilized to test the adequacy of the trajectory model and spatial accuracy of the DIR algorithms studied. a) The 4DCT image sets used in this study consisted of the 6 images spanning the expiratory phases from maximum inhalation (T00) to maximum exhalation (T50). 75 landmark point sets were identified on 10 cases as shown for the example point. Each 4D landmark point was identified (yellow arrow) for phases T00 through T50 as shown. b) A sample 4D trajectory of the landmark point depicted is plotted. Note that the T30 and T40 points overlay each other.