Table 2.
The mean and standard deviation absolute differences (abs diff) between the Dixon-spine-lung sCT method (sCTDSL) and CT for the: Spinal Canal Dmax 0.1 cm3, Lung v20 Gy, Proximal Airways Dmax 0.5 cm3, Oesophagus Dmax 0.5 cm3, Brachial Plexus Dmax 0.5 cm3, Heart Dmax 0.5 cm3, Chest Wall D 30 cm3, Conformity Index at Isodose, PTV D95% and PTV D99% dose-volume metrics. Differences were taken with respect to CT for both Plan 1 (planned on CT and re-calculated on sCTDSL) and Plan 2 (planned on sCTDSL and re-calculated on CT), and did not include the rescaled sCT of patient 2.
| Metric | Plan 1 (abs diff) | Plan 2 (abs diff) | Plan 1 (% diff) | Plan 2 (% diff) |
|---|---|---|---|---|
| Spinal Canal | 20 ± 18 (cGy) | 19 ± 22 (cGy) | 1.2 ± 0.8 | 1.2 ± 1.1 |
| Lung v20 Gy | 0.06 ± 0.10 (%) | 0.07 ± 0.08 (%) | 1.1 ± 1.7 | 1.3 ± 16 |
| Proximal Airways | 11 ± 12 (cGy) | 25 ± 26 (cGy) | 2.2 ± 3.3 | 3.1 ± 3.9 |
| Oesophagus | 21 ± 13 (cGy) | 23 ± 16 (cGy) | 1.3 ± 0.6 | 1.3 ± 0.8 |
| Brachial Plexus | 10 ± 17 (cGy) | 8 ± 16 (cGy) | 1.9 ± 2.9 | 1.4 ± 3.4 |
| Heart | 30 ± 32 (cGy) | 31 ± 30 (cGy) | 1.7 ± 1.0 | 3.0 ± 2.7 |
| Chest Wall | 29 ± 20 (cGy) | 28 ± 17 (cGy) | 1.0 ± 0.7 | 1.0 ± 0.6 |
| Conformity Index | 0.03 ± 0.05 (0–1) | 0.02 ± 0.03 (0–1) | 3.9 ± 6.3 | 2.5 ± 2.8 |
| PTV D95% | 96 ± 135 (cGy) | 85 ± 123 (cGy) | 1.7 ± 2.5 | 1.6 ± 2.4 |
| PTV D99% | 77 ± 119 (cGy) | 84 ± 108 (cGy) | 1.4 ± 2.3 | 1.7 ± 2.2 |