Table 3.
Target volumes and OARs physical dosimetric parameters and comparative analysis between IMRT and ro-IMPT plans
| Dosimetric Parameters | IMRT ((Mean ± SD) | ro-IMPT (Mean ± SD) |
P-value IMRT vs. ro-IMPT |
|---|---|---|---|
| CTV coverage | |||
| CTV HI | 0.04 ± 0.01 | 0.07 ± 0.01 | 0.004* |
| CTV CN | 0.43 ± 0.03 | 0.58 ± 0.05 | 0.004* |
| Stomach | |||
| V55GyE | 2.3 ± 1.0% | 1.0 ± 0.9% | 0.01* |
| V50GyE in cc | 9.8 ± 4.9 cc | 5.5 ± 4.6 cc | 0.01* |
| V50GyE | 4.0 ± 2.1% | 2.3 ± 2.0% | 0.01* |
| V45GyE | 5.8 ± 3.2% | 3.5 ± 3.1% | 0.01* |
| V40GyE | 7.8 ± 4.7% | 5.9 ± 3.7% | 0.01* |
| V30GyE | 13.8 ± 9.2% | 7.5 ± 5.6% | 0.007* |
| V20GyE | 28.7 ± 15.9% | 11.1 ± 7.6% | 0.004* |
| V10GyE | 44.7 ± 18.0% | 17.3 ± 12.0% | 0.004* |
| D0.1cc | 56.4 ± 8.9 GyE | 56.1 ± 8.3 GyE | 0.44 |
| Duodenum | |||
| V55GyE | 1.8 ± 2.0% | 1.2 ± 0.7% | 0.36 |
| V50GyE | 7.5 ± 6.7% | 3.6 ± 2.4% | 0.11 |
| V40GyE | 13.7 ± 11.8% | 11.4 ± 6.5% | 0.16 |
| V30GyE | 22.7 ± 12.4% | 22.9 ± 11.0% | 0.73 |
| V25GyE | 29.5 ± 13.6% | 30.5 ± 13.3% | 0.09 |
| V20GyE | 39.4 ± 15.5% | 39.4 ± 16.8% | 0.49 |
| V10GyE | 62.8 ± 21.3% | 56.5 ± 22.3% | 0.003* |
| D0.1cc | 56.5 ± 5.6 GyE | 55.3 ± 6.4 GyE | 0.17 |
| D1cc | 49.9 ± 7.1 GyE | 49.5 ± 8.1 GyE | 0.42 |
| Small Bowel | |||
| V54GyE | 1.2 ± 1.4% | 0.5 ± 0.8% | 0.02* |
| V50GyE | 2.2 ± 2.5% | 1.2 ± 2.0% | 0.02* |
| V45GyE | 3.5 ± 4.2% | 2.1 ± 3.5% | 0.02* |
| V40GyE | 5.7 ± 6.2% | 2.9 ± 4.7% | 0.01* |
| V30GyE | 19.3 ± 17.0% | 5.1 ± 6.9% | 0.004* |
| V20GyE | 40.5 ± 19.6% | 9.1 ± 9.3% | 0.003* |
| V10GyE | 57.9 ± 15.1% | 17.9 ± 12.5% | 0.004* |
| D0.1cc | 54.8 ± 7.9GyE | 51.0 ± 10.9GyE | 0.057 |
| StoDuo | |||
| V55GyE | 2.3 ± 1.2% | 0.9 ± 0.8% | 0.004* |
| V50GyE in cc | 12.9 ± 5.6 cc | 7.91 ± 4.4 cc | 0.007* |
| V50GyE | 4.5 ± 2.4% | 2.5 ± 1.9% | 0.01* |
| V40GyE | 8.7 ± 4.6% | 5.9 ± 3.7% | 0.02* |
| V30GyE | 15.2 ± 8.3% | 10.1 ± 5.6% | 0.03* |
| V20GyE | 30.6 ± 13.5% | 15.9 ± 7.8% | 0.01* |
| V10GyE | 48.0 ± 15.0% | 23.9 ± 12.7% | 0.004* |
| Kidneys | |||
| Mean dose (GyE) | 6.01 ± 1.16 GyE | 9.82 ± 2.80 GyE | 0.004* |
| V23GyE | 0.04 ± 0.07% | 6.6 ± 6.7% | 0.02* |
| Liver | |||
| Mean dose (GyE) | 6.53 ± 3.2 GyE | 5.64 ± 2.5 GyE | 0.09 |
| V35GyE | 3.0 ± 2.2% | 1.8 ± 1.2% | 0.02* |
| V30GyE | 4.2 ± 3.0% | 2.6 ± 1.6% | 0.03* |
| Spinal Cord | |||
| D0.1cc | 20.8 ± 1.9 GyE | 7.27 ± 4.3 GyE | 0.004* |
Abbreviation: IMRT Intensity-modulated radiotherapy, ro-IMPT Robust Intensity-modulated proton therapy, CTV Clinical target volume, CN Conformation number, HI Homogeneity index, GyE Gray equivalent, cc cubic centimeter, V(X)% percentage volume of OAR at or above “X” GyE, D(X)cc GyE dose of OAR to “X” cc volume, SD Standard deviation
*Significant (P < 0.05)