Table 4.
Dosimetric characteristics comparison for the ipsilateral parotid gland, contralateral parotid gland and oral cavity by treatment with the independent t test
| Ipsilateral Parotid | Contralateral Parotid | Oral Cavity | |||||||
|---|---|---|---|---|---|---|---|---|---|
| IMRT | IMPT | P value | IMRT | IMPT | P value | IMRT | IMPT | P value | |
| Dmean,Gy | 36.5 | 39.0 | 0.037 | 19.9 | 18.9 | 0.30 | 48.4 | 31.4 | <0.001 |
| V5,% | 99.6 | 98.4 | <0.001 | 91.5 | 76.6 | <0.001 | 100.0 | 80.3 | <0.001 |
| V10,% | 82.9 | 91.8 | <0.001 | 58.7 | 60.4 | 0.72 | 99.9 | 70.0 | <0.001 |
| V15,% | 67.9 | 83.3 | <0.001 | 41.6 | 46.2 | 0.21 | 99.2 | 62.0 | <0.001 |
| V20,% | 60.0 | 74.7 | <0.001 | 33.6 | 36.2 | 0.40 | 96.6 | 55.3 | <0.001 |
| V25,% | 54.7 | 66.9 | <0.001 | 28.2 | 28.1 | 0.98 | 91.4 | 49.6 | <0.001 |
| V30,% | 50.5 | 60.1 | <0.001 | 23.9 | 21.4 | 0.29 | 84.0 | 44.6 | <0.001 |
| V35,% | 46.6 | 53.1 | <0.001 | 20.2 | 15.7 | 0.040 | 74.7 | 40.2 | <0.001 |
| V40,% | 42.9 | 46.3 | 0.20 | 16.8 | 11.0 | <0.001 | 64.5 | 36.3 | <0.001 |
| V45,% | 39.2 | 39.4 | 0.90 | 13.3 | 7.2 | <0.001 | 54.9 | 32.7 | <0.001 |
| V50,% | 35.2 | 32.6 | 0.40 | 9.8 | 4.4 | <0.001 | 47.0 | 29.2 | <0.001 |
| V55,% | 30.6 | 25.7 | 0.10 | 6.2 | 2.6 | 0.010 | 39.7 | 25.4 | <0.001 |
| V60,% | 24.7 | 19.2 | 0.10 | 3.2 | 1.5 | 0.090 | 32.7 | 20.9 | <0.001 |
| V65,% | 17.6 | 12.2 | <0.001 | 1.9 | 0.8 | 0.16 | 24.7 | 15.5 | <0.001 |
| V70,% | 9.2 | 5.9 | 0.10 | 0.8 | 0.5 | 0.63 | 13.1 | 9.4 | 0.075 |
The bold values indicate significant statistical differences.
Abbreviations: Dmean, mean dose; Vx, the percent volumes of organ at risk receiving x Gy; IMRT, intensity-modulated (photon) radiation therapy; IMPT, intensity-modulated proton therapy.