Table 3.
The data for OARs sparing for IMRT, VMAT, and Hybrid IMRT/VMAT plans.
| IMRT | VMAT | Hybrid | IMRT versus VMAT | IMRT versus Hybrid | VMAT versus Hybrid | |
|---|---|---|---|---|---|---|
| Mean ± SD | Mean ± SD | Mean ± SD | p value | p value | p value | |
| Normal lung | ||||||
| D 2% (Gy) | 67.5 ± 2.7 | 67.9 ± 3.7 | 67.7 ± 3.2 | >0.05 | >0.05 | >0.05 |
| ∗ V 30 (%) | 18.7 ± 4.1 | 18.4 ± 4.2 | 17.7 ± 3.9 | >0.05 | <0.05 | <0.05 |
| ∗ V 20 (%) | 25.4 ± 4.9 | 25.2 ± 6.1 | 25.5 ± 5.6 | >0.05 | >0.05 | >0.05 |
| ∗ V 10 (%) | 35.2 ± 6.9 | 41.7 ± 8.0 | 38.5 ± 7.3 | <0.05 | <0.05 | <0.05 |
| ∗ V 5 (%) | 50.0 ± 8.2 | 60.3 ± 11.2 | 57.2 ± 10.7 | <0.05 | <0.05 | <0.05 |
| Mean (Gy) | 14.2 ± 2.2 | 15.2 ± 2.6 | 14.6 ± 2.3 | <0.05 | <0.05 | <0.05 |
| Spinal cord | ||||||
| D max (Gy) | 41.5 ± 10.0 | 35.7 ± 10.5 | 35.9 ± 9.0 | <0.05 | <0.05 | >0.05 |
| Esophagus | ||||||
| D max (Gy) | 67.0 ± 5.7 | 66.2 ± 6.9 | 63.7 ± 7.9 | >0.05 | <0.05 | <0.05 |
| Mean (Gy) | 22.9 ± 9.9 | 23.0 ± 9.6 | 22.4 ± 9.7 | >0.05 | <0.05 | <0.05 |
| Heart | ||||||
| D 2% (Gy) | 34.0 ± 25.7 | 31.3 ± 24.0 | 31.6 ± 23.8 | >0.05 | <0.05 | >0.05 |
| Mean (Gy) | 8.5 ± 8.8 | 7.4 ± 7.1 | 7.8 ± 7.8 | <0.05 | <0.05 | >0.05 |
| ∗ V 60 (%) | 1.1 ± 2.0 | 0.9 ± 1.6 | 0.8 ± 1.5 | <0.05 | <0.05 | >0.05 |
| ∗ V 40 (%) | 4.5 ± 5.6 | 2.8 ± 4.0 | 3.2 ± 4.4 | <0.05 | <0.05 | >0.05 |
PTV is planning target volume, IMRT is intensity modulated radiation therapy, VMAT is volumetric modulated arc therapy, CN is conformation number, and HI is homogeneity index.
∗ V N is percentage volume of OARs receiving at least N Gy of radiation dose.