Table 2.
Comparisons of mean dosimetric parameters (across the five cross-validation folds) between the baseline high-resolution Acuros XB (AXB) dose (with a 1 mm grid) and the low-resolution AXB dose (with a 3 mm grid)/predicted high-resolution AXB dose in the planning target volume (PTV), bladder, and rectum.
| ROI | Parameters | AXB | ||
|---|---|---|---|---|
| Baseline(1 mm grid) | 3 mm grid | PredictionAXB 3 model | ||
| PTV | Mean dose (Gy) | 73.0 (3.7) | 73.7 (3.7) | 73.1 (3.7) |
| Max. dose (Gy) | 79.5 (3.3) | 79.0 (3.5) | 79.3 (3.7) | |
| Min. dose (Gy) | 55.3 (4.3) | 60.0 (4.3) | 56.5 (4.0) | |
| V95% (%) | 97.3 (1.0) | 97.8 (0.9) | 97.4 (0.9) | |
| CI | 1.04 (0.02) | 1.04 (0.02) | 1.04 (0.02) | |
| HI | 0.11 (0.02) | 0.11 (0.01) | 0.11 (0.02) | |
| Bladder | Mean dose (Gy) | 16.8 (11.0) | 17.0 (11.1) | 16.8 (10.9) |
| Max. dose (Gy) | 78.3 (3.2) | 78.0 (3.2) | 77.9 (3.5) | |
| Min. dose (Gy) | 1.0 (0.9) | 1.0 (0.9) | 1.0 (0.9) | |
| V70% (%) | 12.8 (11.4) | 13.0 (11.6) | 12.8 (11.5) | |
| V50% (%) | 19.2 (15.8) | 19.7 (16.0) | 19.3 (15.8) | |
| V30% (%) | 27.4 (19.4) | 27.9 (19.7) | 27.4 (19.4) | |
| Rectum | Mean dose (Gy) | 27.3 (8.0) | 27.9 (8.1) | 27.3 (8.0) |
| Max. dose (Gy) | 75.2 (4.2) | 75.3 (4.0) | 74.9 (4.0) | |
| Min. dose (Gy) | 1.0 (0.6) | 1.0 (0.6) | 1.0 (0.6) | |
| V70% (%) | 11.8 (6.6) | 12.9 (6.8) | 11.9 (6.5) | |
| V50% (%) | 29.2 (14.4) | 30.3 (14.4) | 29.2 (14.3) | |
| V30% (%) | 60.8 (16.8) | 61.3 (16.5) | 60.8 (16.7) | |
The Vn% indicates the percentage of the volume irradiated by n% of the prescription dose. Values expressed in bold are not statistically significant (p-value of >0.05). The standard deviations are indicated in parentheses.
ROI, region of interest; HI, homogeneity index; CI, conformity index; AXB, Acuros XB.