Table 3.

Percent difference of the off‐axis ratio between IBA and other systems inside the 120%–130% area of half radiation field. $\text{Mean}\pm \hspace{0.17em}\text{SD}$ (range) inside the 120%–130% area of half radiation field in both positive and negative directions

Depth (mm)	PTW	Standard Imaging	Sun Nuclear
15	$-0.03\pm 0.03(-0.07–+0.03)$	$0.24\pm 0.15(-0.08–+0.41)$	$0.09\pm 0.10(-0.08–+0.26)$
50	$-0.03\pm 0.04(-0.13–+0.03)$	$0.06\pm 0.19(-0.36–+0.29)$	$-0.01\pm 0.15(-0.25–+0.17)$
100	$-0.04\pm 0.04(-0.12–+0.01)$	$0.11\pm 0.19(-0.30–+0.35)$	$-0.04\pm 0.18(-0.30–+0.17)$
200	$0.04\pm 0.09(-0.17–+0.09)$	$0.46\pm 0.23(+0.04-+0.77)$	$0.01\pm 0.19(-0.31–+0.25)$