Artificial intelligence in radiation oncology

Table 2 Target volume segmentation

Ref.	Tumor site	Artificial intelligence technique	Patient number	Contouring	Results
Ikushima et al[39], 2017	Lung	SVM	14 (solid: 6, GGO: 4, mixed GGO: 4)	GTV	DSC: (1) 0.777 for 14 cases; and (2) 0.763 for GGO, 0.701 for mixed GGO
Cui et al[40], 2021	Lung	DVNs	192 (solid: 118, part-solid:53, pure GGO: 21)	GTV	3D-DSC: (1) Solid: 0.838 ± 0.074; (2) Part-solid: 0.822 ± 0.078; and (3) GGO: 0.819 ± 0.059
Zhong et al[41], 2019	Lung	3D-DFCN	60	GTV	DSC: (1) CT: 0.861 ± 0.037; and (2) PET: 0.828 ± 0.087
Kawata et al[42], 2017	Lung	FCM, ANN, SVM	16 (solid: 6, GGO:4, part-solid GGO:6)	GTV	DSC: (1) FCM-based framework:0.79 ± 0.06; (2) ANN-based framework: 0.76 ± 0.14; and (3) SVM-based framework: 0.73 ± 0.14
Li et al[43], 2019	Nasopharynx	U-Net	502	GTV	DSC: (1) Lymph nodes: 65.86%; (2) Primary tumor: 74.00%; HDs: (1) Lymph nodes: 32.10 mm; and (2) Primary tumor:12.85 mm
Zhao et al[45], 2019	Nasopharynx	FCN	30	GTV	DSC: 87.47%
Guo et al[46], 2020	Head and neck	Dense Net and 3D U-Net	250	GTV	DSC: (1) Dense Net with PET/CT: 0.73; (2) Dense Net with PET: 0.67; (3) Dense Net with CT: 0.32; and (4) 3D U-Net with PET/CT: 0.71; MSD: (1) Dense Net with PET/CT: 2.88; (2) Dense Net with PET: 3.38; (3) Dense Net with CT: -; and (4) 3D U-Net with PET/CT: 2.98; HD95: (1) Dense Net with PET/CT: 6.48; (2) Dense Net with PET: 8.29; (3) Dense Net with CT: -; and (4) 3D U-Net with PET/CT: 7.57
Jeong et al[51], 2020	Brain	3D-R-CNN	21	GTV	DSC: 0.90 ± 0.04; HD: 7.16 ± 5.78 mm; MSD: 0.45 ± 0.34 mm; Center of mass distance: 0.86 ± 0.91 mm
Meng et al[54], 2020	Liver	TDP-CNN	106	GTV	DSC: 0.689; HD: 7.69mm; Average distance: 1.07 mm
Elguindi et al[56], 2019	Prostate	2D-CNN, DeepLabV3 +	50	Prostate	Volumetric DSCL: 0.83 ± 0.06; Surface DSC: 0.85 ± 0.11
Men et al[59], 2017	Rectum	DDCNN	278	CTV	DSC: 87.7%

ANN: Artificial neural network; CT: Computed tomography; CTV: Clinical target volume.; DDCNN: Deep dilated convolutional neural network; DFCN: Fully convolutional network; DSC: Dice similarity coefficient; DVNs: Dense V-network; FCM: Fuzzy-c-means clustering method; GGO: Ground-glass opacity; GTV: Gross tumor volume; HD: Hausdorff distance; MSD: Mean surface distance; PET: Positron emission tomography; R-CNN: Region-based convolutional neural network; SVM: Support vector Machine; SVM: Support vector machine; TDP-CNN: Three-dimensional dual-path multiscale convolutional neural network.