Table 4.

Results of Targeting Studies During Surface-based Rigid Registration

Case	Target	No. of points	Mean residual (mm)	Normal distance (mm)
1	Right	1,700	5.1±3.5	4.7±2.5
	Middle	1,500	5.1 ±3.5	5.6±2.7
	Left	2,700	4.8±3.5	9.3±3.7
2	Right	3,000	5.0±3.7	4.5±3.7
	Middle	1,900	4.9±3.6	7.9±4.5
	Left	1,500	4.9±3.7	9.0±5.1
7	Right	1,000	4.5±2.9	5.2±4.3
	Middle	1,600	4.4±2.9	5.5±5.2
	Left	1,300	4.5±3.0	2.6±2.5

In these studies, the targets are based on the inferior ridge of the liver broken into three regions. There are two metrics listed for each target. The first metric is a closest point distance (mean±SEM) in millimeters, which is listed in the fourth column. The second is the root-mean-square (mean±SEM) distance from each point on the preoperative target surface to where its surface normal intersects with the intraoperative target surface.