Table 10.
Low-dose radiation volume of IMRT, VMAT and TOMO in T3-4 NPC patients.
| Median (IQR) | P-value | |||||||
|---|---|---|---|---|---|---|---|---|
| OAR | Objective | IMRT (cm3) | VMAT (cm3) | TOMO (cm3) | P | I vs. V | I vs. T | V vs. T |
| Body | V5 | 7006 (5660-7460) | 7094 (5634-7440) | 6578 (5586-7217) | 0.006 | 1 | 0.016 | 0.016 |
| V10 | 5899 (4937-6415) | 5959 (4944-6436) | 6037 (5087-6669) | <0.001 | 0.495 | 0.016 | <0.001 | |
| V15 | 5316 (4419-5778) | 5337 (4405-5788) | 5386 (4370-6134) | <0.001 | 1 | 0.001 | <0.001 | |
| V20 | 4764 (3904-5193) | 4771 (3929-5204) | 4950 (3849-5532) | <0.001 | 1 | 0.006 | <0.001 | |
| V25 | 4351 (3519-4734) | 4254 (3557-4665) | 4472 (3539-5048) | <0.001 | 0.062 | 0.192 | <0.001 | |
| V30 | 3920 (3141-4290) | 3768 (3147-4098) | 3856 (3102-4409) | 0.004 | 0.004 | 1 | 0.062 | |
IMRT/I, intensity modulated radiation therapy; VMAT/V, volumetric modulated arc therapy; TOMO/T, tomotherapy; OAR, organ at risk; IQR, inter-quartile range; Vx, the volume of organ receiving more or equal to x Gy.