Table 2.
PTV dosimetric results of the VMAT plans used to treat 19 cervical cancer patients devised using three different MSWs
| PTV | Parameter | 0.5 cm MSW | 1.0 cm MSW | 1.5 cm MSW | p 1 | p 2 | p 3 |
|---|---|---|---|---|---|---|---|
| PTV60 | TC (%) | 99.5 ± 0.13 | 99.4 ± 0.16 | 99.18 ± 0.22 | 0.02 | 0.01a | 0.04 |
| Dmean (Gy) | 62.7 ± 0.06 | 62.6 ± 0.05 | 62.73 ± 0.05 | 0.07 | 0.38 | 0.08 | |
| Dmax (Gy) | 65.4 ± 0.23 | 65.2 ± 0.19 | 65.52 ± 0.26 | 0.01a | 0.68 | 0.07 | |
| CI | 0.44 ± 0.02 | 0.51 ± 0.06 | 0.47 ± 0.02 | 0.27 | 0.98 | 0.27 | |
| HI | 1.04 ± 0.00 | 1.04 ± 0.00 | 1.04 ± 0.00 | 0.33 | 0.86 | 0.87 | |
| PTV45 | TC (%) | 99.45 ± 0.12 | 99.28 ± 0.13 | 98.88 ± 0.16 | 0.02 | 0.01a | 0.01a |
| Dmean (Gy) | 49.76 ± 0.39 | 49.72 ± 0.39 | 49.82 ± 0.41 | 0.26 | 0.16 | 0.02 | |
| Dmax (Gy) | 65.66 ± 0.28 | 65.37 ± 0.23 | 65.51 ± 0.22 | 0.01a | 0.782 | 0.11 | |
| CI | 0.75 ± 0.01 | 0.75 ± 0.01 | 0.75 ± 0.01 | 0.37 | 0.54 | 0.92 | |
| HI | 1.27 ± 0.02 | 1.26 ± 0.02 | 1.28 ± 0.02 | 0.02 | 0.01a | 0.00a |
p 1, p‐value comparing 0.5 cm and 1.0 cm MSW plans; p 2, p‐value comparing 0.5 and 1.5 cm MSW plans; p 3, p‐value comparing 1.0 and 1.5 cm MSW plans. PTV, planning target volume; VMAT, volumetric modulated arc therapy; MSW, minimum segment width; TC, target coverage; Dmean, mean dose; Dmax, maximum dose; CI, conformity index; HI, heterogeneity index.
a
statistically significant according to Bonferroni correction.