Table 7.
Low-dose radiation volume of IMRT, VMAT and TOMO in T1-2 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 | 5726 (4576-6701) | 5659 (4548-6905) | 5769 (4706-7105) | <0.001 | 0.433 | <0.001 | 0.045 |
| V10 | 4642 (3794-5479) | 4531 (3782-5501) | 4896 (3796-5825) | 0.001 | 1 | 0.006 | 0.004 | |
| V15 | 4014 (3363-4654) | 3944 (3277-4577) | 4207 (3325-4900) | <0.001 | 0.314 | 0.028 | <0.001 | |
| V20 | 3404 (2946-3960) | 3469 (2900-3978) | 3638 (2894-4173) | 0.002 | 0.991 | 0.045 | 0.002 | |
| V25 | 2973 (2572-3510) | 2987 (2509-3476) | 2932 (2445-3440) | 0.065 | _ | _ | _ | |
| V30 | 2566 (22219-3017) | 2524 (2073-2933) | 2321 (1950-2806) | 0.001 | 0.006 | 0.004 | 1 | |
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.