Automatic Segmentation of Clinical Target Volume and Organs-at-Risk for Breast Conservative Radiotherapy Using a Convolutional Neural Network

Figures & data

Table 1 The Standard Delineation of CTV After BCS

Borders	Cranial	Caudal	Ventral	Dorsal	Lateral	Medial
Residual breast CTV	Upper border of palpable/visible breast tissue; maximally up to the inferior edge of the sterno- clavicular joint	Most caudal CT slice with visible breast	5 mm below the skin surface	Major pectoral muscle or costae and intercostal muscles where no muscle	Lateral breast fold; anterior to the lateral thoracic artery	The edge of sternum

Figure 1 Architecture of (A) deep dilated convolutional neural network (DDCNN), (B) our proposed network, and (C) the residual block used in decoder part of our network.

Table 2 DSC and 95HD for CTV and All OARs

ROI	CTV	Contra-Lateral Breast	Spinal Cord	Heart	Right Lung	Left Lung
DSC±STD
U-ResNet	0.94±0.019	0.94±0.016	0.93±0.024	0.94±0.023	0.96±0.017	0.96±0.025
U-Net	0.93±0.022	0.93±0.020	0.92±0.029	0.93±0.026	0.96±0.018	0.96±0.024
P value	0.001	< 0.001	0.015	0.066	0.257	0.942
95HD±STD (mm)
U-ResNet	4.31±1.76	3.59±1.56	4.37±2.13	4.86±1.48	3.18±1.64	2.79±1.62
U-Net	4.88±1.64	4.15±1.28	5.07±2.26	5.17±2.32	2.89±1.26	2.76±1.52
P value	0.030	0.010	0.003	0.559	0.041	0.781

Figure 2 Boxplots obtained for DSC and 95HD analyses of U-ResNet and U-Net. (A) DSC analyses, (B) 95HD analyses.

Figure 3 CTV and OAR contours generated by (A) GT, (B) U-ResNet, and (C) U-Net after breast conservative surgery.

Table 3 Evaluation for CTV and OARs by Oncologist A

Scores	CTV		Contra-Lateral Breast		Spinal Cord		Heart		Right Lung		Left Lung
	AI	GT	AI	GT	AI	GT	AI	GT	AI	GT	AI	GT
1	0	0	0	0	0	0	0	0	0	0	0	0
2	0.6%	1.9%	0	0	0	0	0	5%	0	0	0	0
3	7%	7.4%	30%	35%	5%	20%	20%	20%	20%	20%	10%	0
4	92.4%	90.7%	70%	65%	95%	80%	80%	75%	80%	80%	90%	100%
P value	0.612		0.414		0.083		0.527		1.00		0.157

Table 4 Evaluation for CTV and OARs by Oncologist B

Scores	CTV		Contra-Lateral Breast		Spinal Cord		Heart		Right Lung		Left Lung
	AI	GT	AI	GT	AI	GT	AI	GT	AI	GT	AI	GT
1	0	0	0	0	0	0	0	0	0	0	0	0
2	0.6%	0.6%	0	0	0	0	0	0	0	0	0	0
3	23.5%	14.9%	10%	15%	0	0	0	0	0	0	0	0
4	75.9%	85.5%	90%	85%	100%	100%	100%	100%	100%	100%	100%	100%
P value	0.612		0.655		1.00		1.00		1.00		1.00

Figure 4 The average CTV scores evaluated by two oncologists.

Table 5 The Consistency Test Between Two Oncologists

CTV Score		Doctor A
		0	1	2	3	Total
Doctor B	0	0	0	0	0	0
	1	0	2	4	17	23
	2	0	5	26	75	106
	3	0	0	17	504	521
	Total	0	7	47	596	650