Table 1.

Summary of reviewed DIR application

Study	Transformation model	Application	Site
Yan et al. [12]	FEM-based linear elastic	Dose accumulation	Prostate cancer
Christensen et al. [14]	Viscous fluid flow	Dose accumulation	Cervix cancer
Schaly et al. [15]	Thin-plate splines	Dose accumulation	Prostate cancer
Velec et al. [16]	FEM-based linear elastic	Dose accumulation	Lung cancer
Sohn et al. [13]	FEM-based linear elastic	Mathematical modeling	Prostate cancer
Nguyen et al. [17]	FEM-based linear elastic	Mathematical modeling	Liver cancer
Budiarto et al. [18]	Thin-plate splines	Mathematical modeling	Prostate cancer
Oh et al. [19]	Parametric active contour	Mathematical modeling	Cervix cancer
Shekhar et al. [20]	B-splines	Automatic segmentation	Lung cancer and abdomen cancer
Chao et al. [21]	Demons algorithm	Automatic segmentation	Head and neck cancer
Lee et al. [22]	Calculus of variance	Automatic segmentation	Head and neck cancer
Wang et al. [23]	Commercial algorithm (Pinnacle)	Automatic segmentation	Head and neck, prostate, and lung cancer
Reed et al. [24]	Demons algorithm	Automatic segmentation	Breast cancer
Guerrero et al. [25]	Optical flow	Functional imaging	Breath hold CT of lung
Yaremko et al. [26]	Optical flow	Functional imaging	4D CT lung
Yamamoto et al. [27]	Calculus of variance	Functional imaging	4D CT lung

DIR, deformable image registration; FEM, finite element method; CT, computed tomography.