Table 2.
The comparison of DVH dose metrics between standard and functional treatment plans (n = 31) are presented for both VMAT and IMPT
| Volumetric Arc Therapy | Intensity Modulated Proton | |||||
|---|---|---|---|---|---|---|
| Standard plan—Mean (SD) | Functional Plan—Mean (SD) | P value | Standard plan—Mean (SD) | Functional Plan—Mean (SD) | P value | |
| CTV metrics | ||||||
| CTV max (RBE[Gy]) | 70.93 (16) | 71.45 (15.9) | 0.1 | 62.09 (5.9) | 62.86 (5.9) | 0.001 a |
| Conformity index | 2.22 (0.7) | 2.15 (0.7) | 0.002 a | 1.79 (0.4) | 1.71 (0.4) | 0.001 a |
| Homogeneity index | 1.22 (0.3) | 1.23 (0.3) | 0.02 | 1.10 (0.2) | 1.11 (0.2) | 0.001 a |
| OAR Metrics | ||||||
| Total MLD (RBE[Gy]) | 16.14 (2.7) | 15.28 (2.9) | <0.001 a | 9.73 (3.3) | 8.78 (2.9) | <0.001 a |
| Total lung V20 (%) | 27.57 (5.7) | 25.50 (6.1) | <0.001 a | 19.54 (6.8) | 17.06 (5.7) | <0.001 a |
| Total lung V5 (%) | 66.8 (11.2) | 64.89 (12.9) | 0.005 | 29.80 (9.2) | 27.67 (8.5) | <0.001 a |
| Esophagus mean (RBE[Gy]) | 24.79 (8.2) | 24.10 (8.6) | 0.005 | 19.57 (10.0) | 19.56 (10.1) | 0.92 |
| Heart mean (RBE[Gy]) | 11.90 (6.2) | 11.88 (6.4) | 0.92 | 4.62 (2.9) | 4.77 (3.5) | 0.75 |
| Cord max (RBE[Gy]) | 36.18 (8.4) | 36.72 (8.4) | 0.46 | 31.84 (9.9) | 33.57 (8.8) | 0.1 |
| Functional lung metrics | ||||||
| Ipsilateral | ||||||
| MLD (RBE[Gy]) | 24.38 (7.2) | 22.49 (7.0) | <0.001 a | 17.65 (7.6) | 14.72 (6.7) | <0.001 a |
| Lung fV5 (%) | 77.9 (17.6) | 76.5 (18.3) | 0.005 | 53.81 (18.2) | 48.10 (17.9) | <0.001 a |
| Lung fV20 (%) | 51.6 (17.1) | 45.57 (16.9) | <0.001 a | 35.83 (16.2) | 28.05 (13.7) | <0.001 a |
| Lung fV30 (%) | 34.9 (16.1) | 30.75 (14.8) | <0.001 a | 26.70 (14.2) | 21.25 (12) | <0.001 a |
| Contralateral | ||||||
| MLD (RBE[Gy]) | 9.26 (3) | 7.99 (2.7) | <0.001 a | 1.75 (2.4) | 1.66 (2.2) | 0.74 |
| Lung fV5 (%) | 69.6 (14.2) | 66.08 (15.3) | 0.015 | 8.24 (11.1) | 6.88 (8.9) | 0.002 a |
| Lung fV20 (%) | 5.79 (6.6) | 4.10 (5.5) | <0.001 a | 2.68 (4.7) | 1.66 (3.1) | 0.004 |
| Lung fV30 (%) | 1.68 (3) | 1.34(2.6) | 0.013 | 1.02 (2.3) | 0.75 (1.7) | 0.015 |
| Total lung | ||||||
| MLD (RBE[Gy]) | 16.05 (3.3) | 14.49 (3.3) | <0.001 a | 8.82 (3.9) | 7.31 (3.3) | <0.001 a |
| Lung fV5 (%) | 73.7 (11.5) | 71.06 (13.3) | 0.003 | 28.78 (11.6) | 25.40 (10.3) | <0.001 a |
| Lung fV10 (%) | 52.8 (13.7) | 43.92 (12.8) | <0.001 a | 24.47 (10.4) | 20.20 (8.4) | <0.001 a |
| Lung fV20 (%) | 26.38 (8.3) | 22.66 (8.2) | <0.001 a | 17.59 (8.4) | 13.48 (6.6) | <0.001 a |
| Lung fV30 (%) | 16.31 (6.9) | 14.30 (6.6) | <0.001 a | 12.49 (6.9) | 9.89 (5.7) | <0.001 a |
| Lung fV40 (%) | 10.54 (6.0) | 9.28 (5.7) | <0.001 a | 9.01 (5.7) | 7.32 (4.9) | <0.001 a |
| Lung fV50 (%) | 5.95 (4.2) | 5.44 (4.2) | 0.006 | 5.78 (4.1) | 4.82 (3.6) | <0.001 |
Functional lung metrics: Using the auto‐segmented functional lung structures from the calculated ventilation map. CTV = iGTV + Margin (Margin = 6 to 10 mm).
Abbreviations: fVX (%), functional %volume that receives X Gy; MLD, mean lung dose; OAR, organ at risk; RBE, relative biological effectiveness.
a
Statistically significant P value with multiple testing corrected alpha level 0.002.