Table 2.

Measured Sc values for rectangular collimator settings for open fields of 6MV-FB and 7MV-UFB of Varian and Siemens linear accelerators.

Collimator setting, X/Y	6MV-FB Clinac iX Varian 2300CD
	4	5	10	15	20	25	30	40
4	0.9511	0.9563	0.9671	0.972	0.9739	0.9745	0.9751	0.9752
5	0.9587	0.961	0.9773	0.9796	0.9801	0.9805	0.9814	0.9823
10	0.973	0.9759	1	1.0049	1.0063	1.0077	1.0086	1.0091
15	0.9798	0.9796	1.0104	1.0163	1.0181	1.0208	1.0222	1.0231
20	0.9856	0.9891	1.0167	1.0222	1.0258	1.0267	1.0289	1.0308
25	0.9872	0.9909	1.0204	1.0267	1.0285	1.0308	1.0326	1.0344
30	0.9903	0.9932	1.0231	1.0289	1.0331	1.0344	1.0376	1.0394
40	0.9952	0.9955	1.0285	1.0358	1.0381	1.0426	1.0449	1.048

Collimator setting, X/Y	6MV-FB Artiste, Siemens
	4	5	10	15	20	25	30	40
4	0.9494	0.9559	0.9649	0.9677	0.9695	0.9709	0.9722	0.9731
5	0.9581	0.9691	0.975	0.9754	0.9759	0.9773	0.9786	0.9795
10	0.9763	0.9795	1	1.0018	1.0045	1.0068	1.0086	1.0096
15	0.9845	0.9859	1.0114	1.0132	1.0164	1.0177	1.0191	1.02
20	0.9854	0.9891	1.015	1.0187	1.0214	1.0228	1.0237	1.0246
25	0.9868	0.9913	1.0159	1.0196	1.0232	1.0241	1.0246	1.025
30	0.9877	0.9936	1.0173	1.0205	1.0246	1.025	1.0255	1.0263
40	0.9891	0.9949	1.0187	1.0214	1.0255	1.0264	1.0273	1.0278

Collimator setting X/Y	7MV-UFB Artiste, Siemens
	4	5	10	15	20	25	30	40
4	0.9658	0.9705	0.9734	0.9738	0.9749	0.9756	0.9758	0.9767
5	0.9798	0.9843	0.9894	0.9907	0.9916	0.9929	0.9939	0.9949
10	0.9886	0.99	1	1.002	1.0033	1.0044	1.0042	1.0062
15	0.9902	0.992	1.0028	1.0062	1.0078	1.008	1.0086	1.0098
20	0.9922	0.9938	1.0053	1.0798	1.0091	1.0104	1.0104	1.0115
25	0.9929	0.9949	1.006	1.0084	1.104	1.0111	1.0115	1.0129
30	0.9936	0.996	1.0067	1.0089	1.0111	1.0118	1.0126	1.013
40	0.9946	0.9969	1.0071	1.0098	1.0115	1.0126	1.0129	1.0138