. 2016 Jul 21;43(8):4734–4741. doi: 10.1118/1.4958962

TABLE I.

Parameters for the collimators used in this study.

Parameters	LEHR	FAN	USCB
Hole size (mm)	1.11	1.5	1.46
Septa (mm)	0.16	0.23	0.24
Hole length (mm)	24.05	34.9^a	37^a
Focal length (mm)	NA	390	200

^{^a}

At location of the perpendicular ray through the focal point.