Table III.

Basic characteristics of commercially available EPIDs. The field size at isocenter is variable for the systems marked by an asterisk. The SDD is source to detector distance. The asterisk indicates SDD is variable. Average resolution calculated from Ref. 45.

Vendor	Elekta	Eliav	Cablon	Siemens	Varian
EPID Type	Video	Video	Video	Video	Ion chamber
Mounting	Rigid	Portable self‐	Retractable	Retractable	Robotic arm
System	removable	contained	adjustable	manually
Field Size at	$25\times 19$	$30\times 25$	$28\times 28$	$30\times 24 140 \text{cm}$	$25\times 25$
Isocenter (cm)	160 cm SDD	140 cm SDD*	140 cm SDD*	SDD	140 cm SDD*
Software Tools	Available	Available	Available	Available	Available
Average spatial resolution (mm)	2.8	1.6	2.3	2.5	1.9