Table 5. AP, LAT, and VERT changes on head-stage coordinates have an effect on the MidACPC coordinates. A head-stage movement is computed by moving +2 mm AP, +2 mm LAT, +2 mm VERT on the left and right trajectories and the resulting MidACPC position is computed. The change in MidACPC from the original target is computed as delta. Finally, a new MidACPC target is chosen on the right and left side and the necessary head-stage adjustments to reach those targets are computed along with the radial error.

AP = Antero-Posterior; LAT = Lateral; VERT = Vertical; MidACPC = Middle of Anterior Commissure and Posterior Commissure; mm = millimeters.

Head-Stage	AP	LAT	VERT		Delta
Right Target	-3	11.5	-3	AP	LAT	VERT
+2 mm AP	-1.31	11.51	-4.06	1.69	0.01	-1.06
+2 mm LAT	-3.31	13.42	-3.47	-0.31	1.92	-0.47
+2 mm VERT	-1.98	12.06	-1.37	1.02	0.56	1.63
New Target	-1	11.5	-3	1.69347	-0.3106348	1.017677
					Radial Error	1.721724
	AP	LAT	VERT		Delta
Left Target	-3	-11.5	-3	AP	LAT	VERT
+2 mm AP	-1.31	-11.49	-4.07	1.69	0.01	-1.07
+2 mm LAT	-2.75	-9.56	-2.58	0.25	1.94	0.42
+2 mm VERT	-1.96	-11.99	-1.36	1.04	-0.49	1.64
New Target	-3	-13.5	-3	-0.01461	-1.9382602	0.492883
					Radial Error	1.938315