TABLE III.
The WEPL errors between the CTref and CBCT images measured in five angular WEPL profiles for each image.
| Absolute error (mean ± SD, mm) | Absolute error (mean ± SD, %)a | |||||
|---|---|---|---|---|---|---|
| Phantom | CBCTraw | CBCTus | CBCTap | CBCTraw | CBCTus | CBCTap |
| Head (L) | 12.4 ± 9.4 | 3.6 ± 3.7 | 1.5 ± 2.0 | 14.3 ± 5.6 | 5.1 ± 4.7 | 1.9 ± 2.4 |
| Head (H) | 10.4 ± 8.0 | 4.6 ± 5.3 | 1.3 ± 1.8 | 11.9 ± 4.8 | 5.6 ± 5.1 | 1.8 ± 2.1 |
| Thorax (L) | 6.6 ± 3.5 | 6.6 ± 6.4 | 3.3 ± 2.6 | 8.3 ± 5.7 | 7.6 ± 7.4 | 3.6 ± 3.0 |
| Thorax (H) | 6.1 ± 3.4 | 7.8 ± 6.7 | 3.0 ± 2.4 | 7.5 ± 4.9 | 9.2 ± 8.6 | 3.4 ± 2.8 |
| Abdomen (L) | 5.0 ± 4.9 | 22.4 ± 9.4 | 2.2 ± 1.4 | 3.5 ± 2.4 | 19.3 ± 6.4 | 1.9 ± 1.0 |
| Abdomen (H) | 5.0 ± 4.9 | 14.6 ± 7.0 | 2.0 ± 1.7 | 3.5 ± 2.4 | 13.1 ± 5.4 | 1.7 ± 1.3 |
| Pelvis (L) | 6.8 ± 4.4 | 12.8 ± 6.7 | 2.8 ± 1.9 | 6.2 ± 4.4 | 12.1 ± 8.2 | 2.2 ± 1.4 |
| Pelvis (H) | 5.8 ± 4.3 | 16.4 ± 7.6 | 2.8 ± 1.9 | 5.2 ± 4.4 | 15.2 ± 9 | 2.2 ± 1.4 |
| Overall | 7.3 ± 5.3 | 11.1 ± 6.6 | 2.4 ± 2.0 | 7.6 ± 4.3 | 10.9 ± 6.9 | 2.3 ± 1.9 |
a
Percentage error relative to the WEPL of CTref; H = high mAs; L = low mAs; SD = one standard deviation.