Figure 3.

Peripheral dose in phantom from 10 MV photons for field sizes (a) $5\times 5{\text{cm}}^2$, (b) $10\times 10{\text{cm}}^2$; (c) $15\times 15{\text{cm}}^2$; and (d) $25\times 25{\text{cm}}^2$ at 10 cm depth, normalized to 100% on the central axis at depth of maximum dose (2.5 cm). Open circles, collimator at 0°, open field; solid circles, collimator at 270°, open field; open squares, collimator at 0°, wedged field; closed squares, collimator at 270°, wedged field; crossed squares, collimator at 180°, wedged field.