Table 2.
Dosimetric parameters for VMAT and ssIMRT cohorts
| Events | VMAT (n = 65) | ssIMRT (n = 130) | P Value |
|---|---|---|---|
| PTV | |||
| Mean dose, Gy | 52.1 ± 1.2 | 51.8 ± 1.5 | .195 |
| CI, % | 87.75 ± 10.70 | 83.20 ± 9.42 | .003 |
| HI, % | 8.41 ± 5.77 | 9.02 ± 6.44 | .507 |
| Lung (%) | |||
| V5 | 49.7 ± 14.7 | 48.1 ± 13.8 | .45 |
| V10 | 40.0 ± 10.8 | 31.4 ± 9.8 | .733 |
| V15 | 23.3 ± 9.6 | 23.3 ± 7.8 | .97 |
| V20 | 16.8 ± 8.3 | 17.3 ± 6.8 | .661 |
| V25 | 11.8 ± 7.0 | 12.3 ± 5.9 | .603 |
| Mean lung dose, Gy | 9.97 ± 3.38 | 9.79 ± 3.05 | .707 |
| Heart (%) | |||
| V5 | 90.6 ± 20.6 | 83.2 ± 27.1 | .036 |
| V10 | 78.5 ± 22.0 | 71.7 ± 26.7 | .079 |
| V20 | 48.1 ± 22.1 | 44.9 ± 22.5 | .337 |
| V30 | 26.5 ± 15.5 | 27.2 ± 17.7 | .798 |
| V40 | 14.0 ± 9.3 | 15.9 ± 11.2 | .239 |
| V50 | 5.2 ± 4.4 | 7.0 ± 5.7 | .016 |
| Mean heart dose, Gy | 22.0 ± 7.1 | 21.0 ± 8.4 | .420 |
| Cordmax, Gy | 38.2 ± 5.8 | 38.9 ± 6.3 | .448 |
CI, conformity index; Cordmax, maximum (point) dose to the spinal cord; HI, homogeneity index; PTV, planning target volume; ssIMRT, step and shoot intensity-modulated radiotherapy; VMAT, volumetric modulated arc therapy.