Table 2.
Dose–volume histogram statistics for target volumes, Level IB and submandibular glands (SMGs)
| Variable | Dmin (Gy) | Dmax (Gy) | Dmean (Gy) (range) |
|---|---|---|---|
| PTVnx | 65.66 ± 6.88 | 75.07 ± 1.51 | 71.17 ± 0.62 |
| PTVnd | 62.83 ± 7.83 | 71.60 ± 2.14 | 68.15 ± 1.40 |
| PTV1 | 37.12 ± 12.84 | 75.09 ± 2.99 | 65.56 ± 1.10 |
| PTV2 | 35.43 ± 19.79 | 62.25 ± 5.52 | 56.22 ± 1.99 |
| IB-L | 24.93 ± 7.23 | 69.06 ± 2.60 | 51.60 ± 5.25 (40.42–64.70) |
| IB-R | 23.81 ± 7.03 | 68.93 ± 2.45 | 52.20 ± 5.26 (37.52–66.33) |
| SMG-L | 36.50 ± 8.23 | 68.87 ± 2.49 | 53.04 ± 4.68 |
| SMG-R | 38.30 ± 8.74 | 68.79 ± 2.49 | 53.64 ± 4.87 |
Dmax, maximum dose; Dmean, mean dose; Dmin, minimum dose; IB-L, left Level IB; IB-R, right Level IB; PTV, planning target volume; PTV1, PTV of the clinical target volume at high risk for involvement; PTV2, PTV of the target volume at low risk for involvement; PTVnd, PTV of enlarged neck lymph nodes; PTVnx, PTV of nasopharyngeal gross tumour volume; SMG-L, left submandibular gland; SMG-R, right submandibular gland.
Values are given as median ± standard deviation.