Figure 4
From: A margin-based analysis of the dosimetric impact of motion on step-and-shoot IMRT lung plans
The effect of varying the drift rate on ∆D 95% for SI, AP and 3D motions are shown in a, b and c respectively, as well as the effect of increasing the total SI drift during treatment (d). Each of the plots shows the effect of changing the drift rate of a 7.2 mm amplitude sinusoidal motion track on target dosimetry for various margin sizes. The shaded regions represent < ±3% change in D95%. Note that the total tumor displacement is equal to the drift displacement plus the sinusoidal amplitude.