Figure 4.

Gamma dose comparison for MFO proton fields. Dose distributions from four fields of a MFO proton plan are measured and compared to their respective calculated doses using both 3D and 2D gamma algorithms. Gamma passing rates obtained from 3D and 2D algorithms are plotted side by side for each field at three different depths: (a) $15\mathrm{g}/{\text{cm}}^2$, (b) $17\mathrm{g}/{\text{cm}}^2$, and (c) $18\mathrm{g}/{\text{cm}}^2$.