Table 1. 3D Point source and plane coordinates used for RT in 3D. SID is 1168 mm, which is known for O-arm2. Note the assumed orthogonality of the AP and LAT planes, which is not necessarily fixed.

AP: Antero-Posterior; LAT: Lateral; VERT: Vertical; SID: Source image distance; RT: Ray tracing.

Point Source			Detector Plane
	AP
AP	653		-515	-515	-515
LAT	-7.5		0	100	0
VERT	93		0	0	100
	LAT
AP	-5		0	100	0
LAT	-655		513	513	513
VERT	5		0	0	100