Table 4.
Low-dose radiation volume of IMRT, VMAT and TOMO in 40 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 | 6231 (5313–7253) | 6371 (5398-7248) | 6348 (5113-7183) | 0.592 | _ | _ | _ |
| V10 | 5110 (4454-6166) | 5181 (4426-6067) | 5490 (4600-6302) | <0.001 | 0.791 | <0.001 | <0.001 | |
| V15 | 4522 (3865-5436) | 4499 (3825-5419) | 4691 (3945-5649) | <0.001 | 0.281 | <0.001 | <0.001 | |
| V20 | 3949 (3391-4772) | 3957 (3316-4847) | 4114 (3370-5086) | <0.001 | 0.656 | <0.001 | <0.001 | |
| V25 | 3519 (2952-4369) | 3485 (2889-4300) | 3471 (2796-4514) | 0.001 | 0.004 | 1 | 0.002 | |
| V30 | 3075 (2523-3970) | 2980 (2468-3807) | 2909 (2279-3921) | <0.001 | <0.001 | 0.011 | 0.353 | |
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.