Table 3.
Differences between Nominal Index and Simple IMRT plans
| Structure | Index IMRT Mean [Range] | Simple IMRT Mean [Range] | p-value |
|---|---|---|---|
| Segment Number* | 47 [34-52] | 18 [6-30] | <0.001 |
| Complexity Score | 0.51 [0.2-0.72] | 0.63 [0.35-0.85] | <0.001 |
| RTOG CI | 1.42 [0.99-2.02] | 1.52 [1.11-2.21] | 0.001 |
| Monitor Units | 1892 [953-3761] | 1695 [934-3832] | 0.012 |
| PTV D95 (Gy) | 42.4 [28.1-60.7] | 42.4 [28.1-60.8] | 0.197 |
| PTV D99 (Gy) | 41.0 [27.3-58.7] | 40.6 [27.2-58.7] | <0.001 |
| PTV Min. 0.5 mL (Gy) | 40.0 [25.7-59.4] | 39.5 [25.7-59.5] | 0.006 |
| PTV EUD (-20) (Gy) | 44.5 [29.4-63.9] | 44.6 [29.6-64.6] | 0.066 |
| Liver NTCP (%) | 2.7 [0-5] | 2.4 [0-5] | 0.370 |
| Effective Liver Volume | 0.38 [0.07-0.7] | 0.38 [0.07-0.71] | 0.418 |
| Mean Liver Dose (Gy) | 15.1 [2.4-20.2] | 15.1 [2.7-19.8] | 0.809 |
| Mean Kidney Dose (Gy) | 3.3 [0-13.7] | 3.4 [0.3-11.7] | 0.509 |
| Max. Cord Dose (Gy) | 16.4 [2.6-24] | 16.2 [2.3-24.8] | 0.713 |
| Max.Stomach Dose (Gy) | 19.6 [1.1-30] | 19.4 [0.6-30] | 0.548 |
| Max. Duodenum Dose (Gy) | 10.1 [0-29.9] | 9.9 [0-29.4] | 0.648 |
| Max. Bowel Dose (Gy) | 9.9 [0-30] | 9.7 [0-30] | 0.545 |
| Max. Esophagus Dose (Gy) | 16.1 [0-30] | 16.1 [0-29.6] | 0.980 |
| Max. Heart Dose (Gy) | 24.5 [0-43.9] | 25.3 | 0.048 |
| Max. Ribs Dose (Gy) | 37.7 [0-48] | 38.2 [0-48] | 0.044 |
| Integral Dose (J) | 68.7 [4.7-181.6] | 69.1 [5.2-173.9] | 0.374 |
* primary endpoint for analysis
Max. is maximum dose to 0.5 mL of relevant structure except for cord where the point maximum dose is reported.