Table 4.

Average magnitude of percent differences for PDD measurements. The PDD measurements are grouped laterally into central axis, left rail, and right rail regions. For each region, the overall agreement (all depths), 0–5 cm depth, and 5–15 cm depth are reported

% Diff. (PDD)	Region	Overall	0–5 cm Depth	5–15 cm Depth
6 MV FFF	Central Axis	2.98%	1.13%	4.11%
	Rt. Rail	3.38%	3.65%	4.19%
	Lt. Rail	4.83%	3.50%	5.64%
10 MV FFF	Central Axis	2.45%	1.12%	3.11%
	Rt. Rail	2.73%	1.27%	3.42%
	Lt. Rail	2.05%	1.93%	2.10%