PMC6349633_01
Original planning computed tomography scan. Yellow indicates internal target volume, and red planning target volume.
gr1.jpg
PMC6349633_01_gr1.jpg
fig1
The planning target volume (PTV) was created using a 5 mm uniform margin around the ITV (Fig 1).
Comparison of the original and repeat 4-dimensional computed tomography (CT) scans. (A) Four-dimensional CT scan after change in tumor position noted on daily cone beam CT scan. (B) Four-dimensional CT scan performed for original planning purposes. (C) Fused image of the original and repeat 4-dimensional CT scans showing tumor changes.
gr2.jpg
PMC6349633_01_gr2.jpg
fig2
At the time of re-simulation, the GTV was determined to have shifted approximately 8 mm inferiorly, 9 mm posteriorly, and 1 mm laterally (3-dimensional distance: 12 mm; Fig 2).