Table 3.
GTV and PTV 95% isodose line coverage.a
| Patient number. Change in volume | GTV coverage on original plan | PTV coverage on original plan | GTV coverage with target volume change (before plan adaptation) | PTV coverage with target volume change (before plan adaptation) | GTV coverage with target volume change (after plan adaptation) | PTV coverage with target volume change (after plan adaptation) | Treatment position offsets before plan adaptationb |
|---|---|---|---|---|---|---|---|
| 1. Increase | 99.86% | 96.16% | 91.7% | 86.84% | 99.78% | 97.12% | Not acceptable |
| 2. Increase | 100% | 95.16% | 93.2% | 89.8% | 100% | 98% | Acceptable |
| 3. Decrease | 99.76% | 96.34% | 100% | 100% | 99.41% | 96.28% | Not acceptable |
| 4. Increase | 99.62% | 97.6% | 92.9% | 88.6% | 99.86% | 97.32% | Acceptable |
a
Target volumes coverage requirements followed ICRU 83 recommendations.
b
Changes in patient anatomy may result in positioning errors; sometimes setup offsets are tolerable, but in some cases cannot be corrected.