Table I.

Elekta precise fractional surface dose: $15\times 15{ \text{cm}}^2$ field size, 100 cm SSD. Values in parentheses are for a Varian 2100C accelerator.

Absorber/Energy	6 MV	10 MV	18 MV
Open	0.171 (.205)	0.159	0.199 (0.215)
Block Tray	0.200 (.226)	0.200	0.256 (0.223)
Universal Wedge (Varian 45° wedge)	0.107 (.179)	0.124	0.176 (0.136)