Table 4.

Validation of registration errors using landmarks. For patients 1 to 3, the landmarks were manually selected in the CT segments and the reference volume. The CT segments used in the validation were randomly selected from the middle to inferior lung and with higher corresponding tidal volumes so that image motions were the largest with respect to the reference volume.

	Landmark pairs	Mean (mm)	Standard deviation (mm)	Maximum (mm)
Patient 1	137	0.98	0.47	2.78
Patient 2	43	1.47	0.95	3.72
Patient 3	43	0.96	0.62	3.08
Full volume 4D-CT	34	1.48	1.34	5.87