Table 3.
Evaluation of PTV maximum (Max), minimum (Min), and prescription isodose for 6 MV flat and FFF beam
| 6 MV Flat Beams | 6 MV FFF Beams | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mean PTV Volume (cc) | Max dose (in % of dose prescribed) | Min dose (in % of dose prescribed) | Prescription Isodose (%) | Max dose (in % of dose prescribed) | Min dose (in % of dose prescribed) | Prescription Isodose (%) | ||||||
| HD a | MM b | HD | MM | HD | MM | HD | MM | HD | MM | HD | MM | |
| 2.39 | 124.8 | 126.7 | 96.2 | 95.2 | 80.4 | 79.2 | 122.8 | 126.1 | 96.6 | 96.4 | 79.3 | 79.4 |
| 5.23 | 122.2 | 128.5 | 96.2 | 95.7 | 82.2 | 78.3 | 121.6 | 124.3 | 96.0 | 95.9 | 81.2 | 77.7 |
| 10.47 | 118.5 | 120.3 | 95.9 | 94.8 | 84.0 | 83.0 | 118.7 | 119.7 | 96.5 | 95.4 | 84.2 | 83.0 |
| 20.18 | 121.1 | 123.8 | 96.6 | 95.3 | 80.6 | 80.2 | 121.1 | 124.6 | 96.4 | 95.7 | 82.5 | 80.8 |
| 40.12 | 123.1 | 123.1 | 95.4 | 94.5 | 81.1 | 80.7 | 121.8 | 123.5 | 95.3 | 95.1 | 81.0 | 81.2 |
| 60.20 | 122.4 | 123.5 | 95.0 | 94.8 | 81.5 | 80.4 | 122.7 | 124.6 | 95.8 | 95.2 | 81.6 | 81.0 |
| 80.60 | 121.8 | 126.7 | 95.4 | 94.1 | 81.2 | 79.9 | 121.7 | 125.2 | 95.7 | 95.1 | 82.0 | 79.0 |
| 100.49 | 123.6 | 124.1 | 94.6 | 94.2 | 80.2 | 80.8 | 124.6 | 123.8 | 96.3 | 95.7 | 81.2 | 81.9 |
| 119.83 | 124.8 | 126.4 | 96.2 | 95 | 79.8 | 80.4 | 125.9 | 123.6 | 96.1 | 94.3 | 81.2 | 80.5 |
| 149.23 | 121.9 | 122.9 | 95.6 | 95.1 | 79.1 | 78.8 | 121.9 | 126.9 | 95.7 | 95.5 | 79.2 | 80.0 |
| Mean | 122.4 | 124.6 | 95.7 | 94.8 | 81.0 | 80.17 | 122.3 | 124.2 | 96.5 | 95.4 | 81.3 | 80.5 |
| STD | 1.857 | 2.42 | 0.623 | 0.499 | 1.37 | 1.29 | 1.953 | 1.929 | 0.417 | 0.564 | 1.45 | 1.51 |
| p‐value | 0.007 | 0.001 | 0.068 | 0.02 | 0.004 | 0.090 | ||||||
a
a HD: 2.5 mm 120 leaf Varian high definition MLC (HDMLC).
b
b MM: 5 mm 120 leaf Varian millennium MLC (MMLC).