Table 1. The dosimetric variation of the nominal plan and RR plan under scenarios of rotated patient planning image CT (-3 and +3 degree along the superior-inferior axis) and verification CT scan (VFCT1 and VFCT2). The ​​​​​​​ is defined as the percentage change of each scenario relative to the plan on the planning CT, which is less affected by the slight dose difference between the nominal plan and RR plan and helps to compare the robustness of the two plans.

CCW: Counter-clockwise; CT: Computed tomography; CTV: Clinical target volume; CW: Clockwise; iGTV: internal gross target volume; RR: Roll robust; VFCT: Verification CT.

	iGTV D95	iGTV D50	CTV D95	​​​​​​​​​​​​​​CTV D50
The nominal plan
-3 degree (CCW)	-10.1%	-4.0%	-14.5%	-3.8%
+3 degree (CW)	-5.9%	-1.8%	-5.8%	-2.1%
VFCT1	-20.2%	-8.9%	-25.6%	-9.9%
VFCT2	-9.2%	-2.0%	-13.8%	-1.8%
RR plan
-3 degree (CCW)	-1.2%	-0.8%	-1.2%	-0.2%
+3 degree (CW)	-3.3%	-1.4%	-3.2%	-1.0%
VFCT1	-5.4%	-2.4%	-7.3%	-1.8%
VFCT2	-2.7%	-0.3%	-4.7%	0.0%