MRI-Based Radiotherapy Planning to Reduce Rectal Dose in Excess of Tolerance

Figure 3

Discordance between CT and MR prostate contour by quadrant. Absolute volume (a) and percent overlap (b) of CT PTV3 mm and MR PTV5 mm are shown. (c) Percent volume by quadrant where the CT PTV3mm extends outside MR PTV5 mm is shown in blue, and percent volume by quadrant where the MR PTV5 mm extends outside the CT PTV3 mm is shown in red. Graphical representation of regions of discordance between CT PTV3 mm and MR PTV5 mm is shown in the panels. (d) Volume in green shows areas were the MR PTV5 mm extends outside the CT PTV3 mm, and volume in blue shows areas were the CT PTV3 mm extends outside the MR PTV5 mm. (e) Location (by quadrant) where CT PTV3 mm extends outside the MR PTV5 mm is shown. (f) Location (by quadrant) where MR PTV5 mm extends outside the CT PTV3 mm is shown. All panels show mean ± standard deviation. In panels A and C, individual values for all 15 subjects are shown.  < 0.05,  < 0.01, and  < 0.001 by two-tailed paired Student’s t-test or signed rank test.

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