Table 3 Conformality and V20 constraints, as per the RTOG 0813 protocol [16]
PTV Volume (cc) | Ratio of prescription isodose volume to the PTV bolume (R100) | Ratio of 50% prescription isodose volume to the PTV volume, (R50) | Maximum dose (in % of dose prescribed) @ 2 cm from PTV in any direction, (D2cm) (Gy) | Percent of Lung receiving 20 Gy total or more (V20) | ||||
|---|---|---|---|---|---|---|---|---|
Deviation | Deviation | Deviation | Deviation | |||||
None | Minor | None | Minor | None | Minor | None | Minor | |
1.8 | < 1.2 | < 1.5 | < 5.9 | < 7.5 | < 50.0 | < 57.0 | < 10 | < 15 |
3.8 | < 1.2 | < 1.5 | < 5.5 | < 6.5 | < 50.0 | < 57.0 | < 10 | < 15 |
7.4 | < 1.2 | < 1.5 | < 5.1 | < 6.0 | < 50.0 | < 58.0 | < 10 | < 15 |
13.2 | < 1.2 | < 1.5 | < 4.7 | < 5.8 | < 50.0 | < 58.0 | < 10 | < 15 |
22.0 | < 1.2 | < 1.5 | < 4.5 | < 5.5 | < 54.0 | < 63.0 | < 10 | < 15 |
34.0 | < 1.2 | < 1.5 | < 4.3 | < 5.3 | < 58.0 | < 68.0 | < 10 | < 15 |
50.0 | < 1.2 | < 1.5 | < 4.0 | < 5.0 | < 62.0 | < 77.0 | < 10 | < 15 |
70.0 | < 1.2 | < 1.5 | < 3.5 | < 4.8 | < 66.0 | < 86.0 | < 10 | < 15 |
95.0 | < 1.2 | < 1.5 | < 3.3 | < 4.4 | < 70.0 | < 89.0 | < 10 | < 15 |
126.0 | < 1.2 | < 1.5 | < 3.1 | < 4.0 | < 73.0 | > 91.0 | < 10 | < 15 |
163.0 | < 1.2 | < 1.5 | < 2.9 | < 3.7 | < 77.0 | > 94.0 | < 10 | < 15 |