1. Dosimetric Benefits and Practical Pitfalls of Daily Online Adaptive MRI-Guided Stereotactic Radiation Therapy for Pancreatic Cancer 
Nancy El-Bared, MD, Lorraine Portelance, MD, Benjamin O. Spieler, MD, Deukwoo Kwon, PhD, Kyle R. Padgett, PhD, Karen M. Brown, CMD, Eric A. Mellon, MD, PhD 
Practical Radiation Oncology 
Volume 9, Issue 1, Pages e46-e54 (January 2019)
DOI: /j.prro
Copyright © 2018 American Society for Radiation Oncology Terms and Conditions

2. Figure 1
Dot plots demonstrate nonadaptive (NA) and adaptive (A) fraction target volume and organ-at-risk doses for 10 patients treated with 5-fraction stereotactic body radiation therapy. Red vertical lines in each figure indicate the objective doses. For each NA and A plan, plotted are planning target volume (PTV) at 100% isodose (PTV100) (prescription 90%) (A), bowel maximum dose (goal Dmax 38 Gy) (B), stomach V33 Gy (volume receiving 33 Gy or more; goal V33 Gy <1 cm3) (C), stomach maximum dose (goal Dmax 38 Gy) (D), duodenum V33Gy (goal V33 Gy <1 cm3) (E), and duodenum maximum dose (goal Dmax 38 Gy) (F). Each patient's fraction is represented by a different color as per the legend. The results of this figure are summarized in Table 2. At a glance, adaptive plans always put the prescription dose (90%) into the PTV (A) and they put less dose into stomach and duodenum (fewer dots to the left of the red line in C-F). However they can put more dose into the bowel (B, more dots to the right of the red line) because of large interfraction variability of the large bowel and tendency not to weight the large bowel as strongly in the optimizer objectives when it was not initially at risk.
Practical Radiation Oncology 2019 9, e46-e54DOI: ( /j.prro )
Copyright © 2018 American Society for Radiation Oncology Terms and Conditions

3. Figure 2
The stomach (green) is much larger between a single patient's (patient 2 in Figs 1 and 3) planning magnetic resonance imaging (MRI) (A) and third fraction setup MRI (B). Additional contours shown: liver (blue), duodenum (yellow), spinal canal (dark blue), kidneys (pink), bowel loops (orange), and gross tumor volume (red).
Practical Radiation Oncology 2019 9, e46-e54DOI: ( /j.prro )
Copyright © 2018 American Society for Radiation Oncology Terms and Conditions

4. Figure 3
Stomach volume observed for the planning magnetic resonance imaging (MRI) (fraction 0) and the 5 subsequent treatment setup MRI scans (A). Plotted against change in stomach volume (%) are changes in: planning target volume at 100% isodose (PTV100) (B), stomach V33 Gy (volume receiving 33 Gy or more) (C), stomach maximum dose (Dmax) (D), duodenum V33 Gy (E), and duodenum Dmax (F).
Practical Radiation Oncology 2019 9, e46-e54DOI: ( /j.prro )
Copyright © 2018 American Society for Radiation Oncology Terms and Conditions

5. Figure 4
Plan 20 Gy isodose line comparison between a nonadaptive and an adaptive fraction where the spinal canal 20 Gy dose objective was violated. The nonadaptive plan (A) demonstrates that the spinal canal (blue contour) is not within the 20 Gy isodose line (red), whereas the adaptive plan (B) isodose line has been shifted to include the entire spinal canal. Planning target volume is contoured in magenta.
Practical Radiation Oncology 2019 9, e46-e54DOI: ( /j.prro )
Copyright © 2018 American Society for Radiation Oncology Terms and Conditions