TABLE II.

Dice similarity metric computed for critical organs before and after deformable registration.

Patient No./MVCT No.	Rigid alignment			Deformable registration
	Bladder	Rectuma	Prostate	Bladder	Rectuma	Prostate
Prostate $1∕1$	0.44	0.72	0.81	0.95	0.77	0.91
Prostate $1∕2$	0.37	0.61	0.71	0.97	0.78	0.96
Prostate $2∕1$	0.76	0.62	0.30	0.96	0.81	0.87
Prostate $2∕2$	0.56	0.58	0.41	0.97	0.83	0.88
Prostate $3∕1$	0.44	0.58	0.43	0.97	0.81	0.92
Prostate $3∕2$	0.50	0.62	0.64	0.97	0.79	0.95
GYN $1∕1$	0.57	0.63	—	0.96	0.77	—
GYN $1∕2$	0.52	0.56	—	0.93	0.93	—
GYN $2∕1$	0.40	0.69	—	0.92	0.83	—
GYN $2∕2$	0.70	0.56	—	0.92	0.78	—
Average	0.52	0.62	0.55	0.95	0.81	0.92

^aFor rectum, the Dice metric is computed only on the slices that rectum was contoured on MVCT images because rectum could have been contoured for different number of slices on MVCT and kVCT.