Table 2 Mean dose (standard deviation) of target volumes and normal organs at risk—VMAT versus IMRT
Variables | IMRT (n = 74) | VMAT (n = 66) | P value |
|---|---|---|---|
GTV, mean | 7458 (85) | 7457 (84) | 0.93 |
PTV-H, mean | 7369 (49) | 7363 (47) | 0.44 |
PTV-M, mean | 6826 (214) | 6788 (172) | 0.26 |
PTV-L, mean | 5694 (178) | 5660 (74) | 0.25 |
Brain stem, maximum | 5108 (419) | 5094 (387) | 0.84 |
Spinal cord, maximum | 4188 (225) | 4095 (215) | 0.02 |
Right eyeball, mean | 821 (489) | 877 (269) | 0.42 |
Left eyeball, mean | 805 (289) | 902 (319) | 0.08 |
RT optic nerve | 4244 (951) | 4574 (978) | 0.11 |
Lt optic nerve | 4416 (1070) | 4657 (809) | 0.21 |
Right parotid, mean | 2970 (568) | 2912 (383) | 0.51 |
Left parotid, mean | 3017 (482) | 2949 (463) | 0.48 |
Oral cavity, mean | 3796 (479) | 3713 (428) | 0.32 |
Larynx, mean | 3976 (516) | 3919 (431) | 0.52 |
Cervical esophagus, mean | 3712 (420) | 3836 (455) | 0.19 |