Table 2.

Rotations about the LR, AP, and IS axes of the five cervical vertebrae compared to the CBCT reference images taken at the first treatment fraction. Values are expressed as mean (SD) [range].

	Left-right (deg)	Anterior-posterior (deg)	Inferior-superior (deg)
C1	0.4 (2.1) [−3.3 to 5.1]	0.2 (1.0) [−1.9 to 1.9]	−0.4 (2.6) [−3.4 to 6.6]
C2	2.2 (3.2) [−3.0 to 7.5]	0.1 (1.2) [−2.8 to 2.6]	0.2 (2.6) [−4.0 to 5.8]
C3	2.1 (3.6) [−4.7 to 7.8]	0.2 (1.2) [−1.9 to 2.9]	0.0 (2.5) [−4.4 to 4.7]
C4	1.5 (3.3) [−5.0 to 6.1]	−0.1 (1.6) [−2.5 to 3.2]	−0.1 (2.6) [−5.2 to 4.3]
C5	0.2 (2.8) [−3.8 to 5.4]	0.7 (1.3) [−1.3 to 3.2]	0.4 (2.2) [−4.1 to 3.9]