Table 3.

Overview of RL in medical image registration.

References	ROI	Dimension	Modality	Transformation
(Ghesu et al 2016; Ghesu et al 2019)	Cardiac, HN	2D, 3D	MR, CT, US	NA
(Krebs et al 2017)	Prostate	3D-3D	MR	Deformable
(Liao et al 2016)	Spine, Cardiac	3D-3D	CT-CBCT	Rigid
(Ma et al 2017)	Chest, Abdomen	2D-2D	CT-Depth Image	Rigid
(Miao et al 2017)	Spine	3D-2D	3DCT-Xray	Rigid
(Zheng et al 2018)	Spine	3D-2D	3DCT-Xray	Rigid
(Sun et al 2019)	Nasopharyngeal	2D-2D	MR-CT	Rigid with scaling