Impact evaluation of intra-fractional variation on online adaptive radiotherapy for postoperative cervical and endometrial cancer

Table 1 Comparison of target volume and organs at risk contours before and after treatment

Region	ASD (mm)	DSC	95% HD (mm)	Posterior-anterior (mm)	Left-right (mm)	Superior-inferior (mm)
CTV-N	0.83 ± 0.33	0.9 ± 0.09	3.94 ± 1.17	0.75 ± 1.05	-0.14 ± 1.31	-0.71 ± 6.69
CTV-V	1.69 ± 0.74	0.8 ± 0.11	6.42 ± 2.45	0.46 ± 2.58	-0.11 ± 1.42	-0.58 ± 7.27
Bladder	1.75 ± 1.02	0.91 ± 0.04	7.24 ± 3.92	0.34 ± 2.01	-0.20 ± 1.09	-1.02 ± 5.57
Rectum	1.71 ± 1.09	0.81 ± 0.08	7.67 ± 4.54	0.17 ± 2.09	0.27 ± 1.59	1.38 ± 8.12
Bowel	3.56 ± 1.79	0.6 ± 0.25	18.8 ± 14	-3.99 ± 4.17	0.29 ± 6.07	1.47 ± 31.08

Positive values of centroid deviation indicate shifts towards the inferior, right, and anterior directions, while negative values reflect superior, left, and posterior shifts. ASD: Average surface distance; DSC: Dice similarity coefficient; HD: Hausdorff distance; CTV-N: Novel clinical target volume; CTV-V: Clinical target volume that includes the proximal vagina and any paravaginal tissue.

Table 2 Dosimetric outcomes of target volume and organs at risks

ROIs	Dosimetric metrics	Adapted plan + iCBCT1	Adapted plan + iCBCT2	Scheduled plan + iCBCT1	Scheduled plan + iCBCT2	P1 value	P2 value
CTV-N	V100% (%)	99.94 ± 0.09	99.08 ± 8.88	97.02 ± 6.47	96.40 ± 10.72	0.45	0.34
CTV-N	D99% (%)	100.87 ± 0.20	100.04 ± 8.96	100.03 ± 1.41	99.36 ± 9.07	0.99	0.16
CTV-V	V100% (%)	99.97 ± 0.05	98.66 ± 9.02	96.11 ± 3.71	96.41 ± 9.80	< 0.05	0.58
CTV-V	D99% (%)	100.84 ± 0.19	99.07 ± 10.57	92.97 ± 9.00	95.65 ± 11.15	< 0.05	< 0.05
Bladder	V40Gy (%)	24.62 ± 4.54	26.22 ± 5.32	26.16 ± 5.80	27.35 ± 6.00	< 0.05	< 0.05
	V30Gy (%)	38.49 ± 5.93	40.25 ± 6.28	40.62 ± 6.96	41.80 ± 6.83	< 0.05	< 0.05
	V20Gy (%)	59.72 ± 7.05	61.54 ± 7.01	63.13 ± 8.99	64.19 ± 8.37	< 0.05	0.09
	V10Gy (%)	92.40 ± 3.78	92.91 ± 3.40	94.10 ± 3.91	94.19 ± 3.55	< 0.05	0.75
	Dmean (Gy)	26.77 ± 1.95	27.38 ± 2.06	27.71 ± 2.55	28.10 ± 2.48	< 0.05	< 0.05
Rectum	V40Gy (%)	38.18 ± 9.26	37.36 ± 11.01	39.39 ± 14.46	37.74 ± 13.82	0.47	0.11
	V30Gy (%)	56.53 ± 10.42	56.49 ± 11.36	59.77 ± 14.15	58.79 ± 13.53	0.06	0.33
	V20Gy (%)	74.13 ± 9.64	74.70 ± 9.79	79.11 ± 10.51	78.84 ± 10.04	< 0.05	0.71
	V10Gy (%)	94.27 ± 4.61	94.42 ± 4.67	95.54 ± 4.01	95.71 ± 3.75	< 0.05	0.55
	Dmean (Gy)	31.67 ± 3.39	31.61 ± 3.60	32.82 ± 4.29	32.48 ± 4.00	0.06	0.26
Bowel	V40Gy (%)	12.48 ± 6.39	9.92 ± 5.44	12.93 ± 6.73	10.24 ± 5.83	< 0.05	< 0.05
	V30Gy (%)	23.83 ± 10.91	21.11 ± 10.38	25.38 ± 11.99	22.11 ± 11.36	< 0.05	< 0.05
	V20Gy (%)	41.30 ± 17.02	39.45 ± 17.04	47.04 ± 19.78	44.79 ± 19.83	< 0.05	0.11
	V10Gy (%)	60.24 ± 24.25	59.60 ± 24.74	69.08 ± 27.92	68.75 ± 28.37	0.36	0.88
	Dmean (Gy)	18.05 ± 7.33	17.23 ± 7.17	19.83 ± 8.12	18.93 ± 7.91	0.07	0.12

¹The comparison between adapted plan + iterative cone-beam computed tomography (iCBCT) pretreatment iCBCT scan and adapted plan + posttreatment iCBCT scan.

²The comparison between scheduled plan + pretreatment iCBCT scan and scheduled plan + posttreatment iCBCT scan.

iCBCT₁: Pretreatment iterative cone-beam computed tomography scan; iCBCT₂: Posttreatment iterative cone-beam computed tomography scan; CTV-N: Novel clinical target volume; CTV-V: Clinical target volume that includes the proximal vagina and any paravaginal tissue.