Figure 4.
Difference in the D1-D99 from the 3D and 4D simulations for the larger (a) and smaller (c) spot sizes. The D1-D99 values from the 4D simulations are shown in (b) and (d) for the larger and smaller spot sizes respectively. All values are percentages of the prescribed dose per fraction. The data points are the average values from the eight different starting breathing phases and the error bars represent ±1 SD. IMPT20% = single field homogeneity (SFH) restricted to ≤20%, IMPTfull = no restriction on SFH.