Figure 5.

Interplay effects evaluation in intensity‐modulated proton therapy (IMPT) using the dose–volume histogram indices with interplay effects considered, including (a) clinical target volume (CTV_high) D_95% and${\mathrm{D}}_{2\mathrm{c}{\mathrm{m}}^3}$, and CTV_low D_95% normalized to the prescription dose. (b) CTV_high D_5%‐D_95% normalized to the prescription dose. (c) Lung D_mean, cord D_max and${\mathrm{D}}_{0.03\mathrm{c}{\mathrm{m}}^3}$ _, heart D_mean, and liver D_mean in absolute dose. (d) Stomach V_45Gy[RBE] in absolute volume. (e) Lung V_5Gy[RBE] and V_20Gy[RBE], heart V_20Gy[RBE], V_30Gy[RBE] and V_40Gy[RBE], left, right, and total kidneys V_18Gy[RBE], and liver V_30Gy[RBE] in relative volume. In each box plot, the five horizontal lines from top to bottom are the maximum, third quartile, median, first quartile, and minimum value of the corresponding DVH index for the whole group excluding the outliers respectively. The grey points are the outliers as defined in Statistical Analysis subsection. The blue boxes are the IMPT results and white boxes are the VMAT results. At our clinics it is required to have CTV D_95% is at least 95% of the prescription dose for targets and the cord D_max < 45 Gy[RBE] under the influence of interplay effects. Abbreviations: RBE = relative biological effectiveness.