Table II.

Summary of the geometry parameters used for the six participating sites. The QA dose plane parameters were the ones used for both: a) actual MapCHECK measurements (for comparisons/commissioning) and b) simulated dose planes resulting from a conversion of the EPID images.

Site / EPID Vendor	Source-to-EPID Distance (cm)	Source-to-QA Dose Plane (cm)	QA Dose Plane Depth (cm)
A / Varian	140.0	100.0	5.0
B / Varian	100.0	100.0	10.0
C / Siemens	100.0	100.0	5.0
D / Varian	120.0	100.0	5.0
E / Varian	105.0	95.0	5.0
F / Varian	105.0	100.0	5.0