TABLE 4.
Dose differences between deformed computed tomography (dCT) and synthetic CT (sCT) for target volumes at dose–volume histogram (DVH) points
| Cases | Target | DVH point | Physical dose difference (%) | BED difference (%) | ||
|---|---|---|---|---|---|---|
| Mean (1SD) | [min, max] | Mean (1SD) | [min, max] | |||
| All | PTV (N = 17) | D 2% | 0.5 (0.9) | [–0.5, 2.6] | 0.8 (1.4) | [–0.8, 3.9] |
| D 50% | 0.6 (0.8) | [–0.5, 2.6] | 0.8 (1.2) | [–0.8, 4.0] | ||
| D 98% | 0.5 (0.8) | [–0.5, 2.6] | 0.6 (1.1) | [–1.3, 3.7] | ||
| SBRT | PTV (N = 15) | D 99% | 0.4 (1.0) | [–0.8, 3.2] | 0.6 (1.4) | [–1.2, 4.0] |
| GTV (N = 15) | D 0.1cc | 0.4 (1.1) | [–1.7, 2.6] | 0.6 (1.8) | [–2.5, 4.2] | |
| D mean | 0.6 (0.9) | [–0.7, 2.7] | 0.9 (1.4) | [–1.0, 4.1] | ||
| D 99% | 0.5 (0.9) | [–0.9, 2.3] | 0.7 (1.4) | [–1.3, 3.3] | ||
| Prostate | PTV (N = 2) | D 2% | 0.1 (0.2) | [0.0, 0.3] | 0.1 (0.3) | [–0.1, 0.3] |
| D 50% | 0.2 (0.1) | [0.1, 0.2] | 0.2 (0.1) | [0.2, 0.3] | ||
| D 98% | 0.2 (0.2) | [0.1, 0.4] | 0.3 (0.2) | [0.2, 0.4] | ||
| CTV (N = 2) | D 98% | 0.2 (0.0) | [0.2, 0.2] | 0.2 (0.1) | [0.2, 0.3] | |
Note: The mean with one standard deviation (1SD) and range for both physical dose and biologically effective dose (BED) difference are presented. The values are given in percent relative to the dCT‐based dose.
Abbreviations: CTV, clinical target volume; GTV, gross tumor volume; PTV, planning target volume; SBRT, stereotactic body radiation therapy.