Table 3.
Dose-volumetric parameters of OARs and whole body
| OAR | DV parameter | VMAT | IMRT with MR-linac | p |
|---|---|---|---|---|
| Bronchi | Maximum dose (Gy) | 24.2 ± 21.7 | 20.4 ± 19.0 | < 0.001 |
| V34.8Gy (cm3) | 0.5 ± 2.0 | 0.0 ± 0.1 | 0.223 | |
| Esophagus | V30Gy (cm3) | 0.0 ± 0.0 | 0.0 ± 0.0 | – |
| Heart | Maximum dose (Gy) | 20.2 ± 16.0 | 19.1 ± 13.7 | 0.087 |
| V34Gy (cm3) | 0.7 ± 2.4 | 0.0 ± 0.1 | 0.168 | |
| Ipsilateral lung | Mean dose (Gy) | 5.7 ± 2.0 | 5.2 ± 2.1 | 0.041 |
| V20Gy (cm3) | 134.8 ± 81.4 | 116.8 ± 80.9 | 0.025 | |
| V10Gy (cm3) | 275.3 ± 139.3 | 244.7 ± 140.2 | 0.047 | |
| V5Gy (cm3) | 414.7 ± 182.0 | 358.1 ± 172.9 | < 0.001 | |
| D1500cc (Gy) | 0.13 ± 0.25 | 0.24 ± 0.37 | 0.001 | |
| D1000cc (Gy) | 0.61 ± 1.15 | 0.76 ± 0.94 | 0.012 | |
| Contralateral lung | Mean dose (Gy) | 0.9 ± 0.4 | 1.0 ± 0.6 | 0.210 |
| V20Gy (cm3) | 0.0 ± 0.0 | 6.6 ± 20.1 | 0.146 | |
| V10Gy (cm3) | 0.5 ± 1.6 | 23.1 ± 44.3 | 0.029 | |
| V5Gy (cm3) | 23.4 ± 37.1 | 49.8 ± 72.1 | 0.049 | |
| D1500cc (Gy) | 0.06 ± 0.10 | 0.11 ± 0.14 | 0.002 | |
| D1000cc (Gy) | 0.21 ± 0.28 | 0.28 ± 0.17 | 0.046 | |
| Rib | Maximum dose (Gy) | 47.2 ± 16.5 | 43.0 ± 12.9 | 0.032 |
| V40Gy (cm3) | 7.7 ± 13.0 | 1.8 ± 3.9 | 0.008 | |
| Skin | Maximum dose (Gy) | 27.8 ± 9.4 | 33.0 ± 4.4 | 0.018 |
| V36Gy (cm3) | 0.1 ± 0.4 | 0.1 ± 0.2 | 0.167 | |
| Spinal cord | Maximum dose (Gy) | 11.0 ± 5.1 | 14.5 ± 5.6 | 0.002 |
| V26Gy (cm3) | 0.0 ± 0.0 | 0.0 ± 0.0 | – | |
| Whole body | Mean dose (Gy) | 1.2 ± 0.5 | 0.9 ± 0.3 | < 0.001 |
| V50% (cm3) | 103.5 ± 82.8 | 78.7 ± 62.9 | < 0.001 |
Note: OAR organ at risk, DV parameter dose-volumetric parameter, VMAT volumetric modulated arc therapy, IMRT intensity modulated radiation therapy, MR-linac magnetic resonance image linear accelerator, VnGy percent volume receiving n Gy, Dncc dose received by at least n cc volume of the planning target volume, Vn% percent volume receiving n% of the prescription dose