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Table 5 Plan parameters stratified by patient

From: Multi-institutional comparison of volumetric modulated arc therapy vs. intensity-modulated radiation therapy for head-and-neck cancer: a planning study

   Patient Technique 1 2 3 4 5
PTVboost CI95 VMAT 1.37 ± 0.03 1.41 ± 0.06 1.46 ± 0.10 1.30 ± 0.03 1.31 ± 0.03
IMRT 1.54 ± 0.09 1.44 ± 0.04 1.50 ± 0.07 1.33 ± 0.05 1.42 ± 0.17
PTVtotal CI95 VMAT 1.43 ± 0.06 1.58 ± 0.07 1.52 ± 0.04 1.57 ± 0.08 1.40 ± 0.04
IMRT 1.53 ± 0.04 1.71 ± 0.09 1.63 ± 0.06 1.67 ± 0.10 1.57 ± 0.11
Spinal cord D1% (Gy) VMAT 42.1 ± 5.5 44.7 ± 2.6 43.4 ± 3.5 44.0 ± 4.1 42.9 ± 3.6
IMRT 43.8 ± 4.3 44.3 ± 2.9 44.8 ± 2.4 44.5 ± 4.7 44.4 ± 4.2
Brain stem D1% (Gy) VMAT 48.3 ± 4.7 42.1 ± 6.0 45.5 ± 5.6 41.4 ± 6.9 41.7 ± 5.0
IMRT 48.2 ± 1.9 45.7 ± 4.3 47.6 ± 4.2 40.5 ± 3.6 37.9 ± 5.0
Parotid gland ipsilateral Dmean (Gy) VMAT 21.7 ± 2.0 30.3 ± 4.9 24.8 ± 3.5 38.1 ± 9.2 25.1 ± 2.4
IMRT 23.6 ± 1.7 33.3 ± 3.5 30.5 ± 10.2 41.8 ± 11.0 26.3 ± 3.2
Parotid gland contralateral Dmean (Gy) VMAT 21.1 ± 1.9 23.1 ± 1.0 22.1 ± 2.1 25.0 ± 2.9 18.6 ± 1.9
IMRT 23.2 ± 1.9 24.1 ± 1.3 24.2 ± 0.5 25.3 ± 3.5 19.4 ± 1.5
Submandibular gland contralateral Dmean (Gy) VMAT 49.2 ± 6.0 55.0 ± 6.3 -- -- 54.8 ± 4.3
IMRT 49.6 ± 5.6 57.4 ± 6.4 -- -- 55.7 ± 3.7
Oral cavity Dmean (Gy) VMAT 31.3 ± 4.8 34.7 ± 5.4 33.3 ± 7.0 47.7 ± 1.7 36.5 ± 7.4
IMRT 34.2 ± 4.8 38.2 ± 3.1 37.4 ± 8.9 48.8 ± 1.7 38.7 ± 7.2
Larynx Dmean (Gy) VMAT 43.2 ± 4.4 44.9 ± 7.3 47.1 ± 4.6 46.8 ± 5.5 45.3 ± 5.5
IMRT 44.5 ± 4.3 45.5 ± 5.8 47.5 ± 4.2 47.7 ± 4.7 47.0 ± 3.9
Pharyngeal constrictors° Dmean (Gy) VMAT 42.3 ± 3.9 50.5 ± 6.6 48.9 ± 2.6 48.0 ± 4.9 45.7 ± 5.2
IMRT 42.1 ± 2.7 48.2 ± 3.7 49.3 ± 2.3 47.9 ± 3.6 46.9 ± 2.6
Mandible° Dmean (Gy) VMAT 41.7 ± 1.3 45.1 ± 1.4 55.2 ± 1.7 54.2 ± 1.5 46.7 ± 1.7
IMRT 42.4 ± 0.9 47.2 ± 1.2 57.6 ± 1.5 55.2 ± 1.6 48.9 ± 1.7
Effective delivery time (min:sec) VMAT 5:38 ± 0:42 6:00 ± 0:48 6:22 ± 1:28 6:07 ± 1:31 5:26 ± 1:04
IMRT 12:52 ± 0:41 13:09 ± 2:18 13:46 ± 1:07 13:30 ± 1:50 12:57 ± 2:23
MUs -- VMAT 581 ± 55 641 ± 90 735 ± 170 668 ± 91 589 ± 73
   IMRT 702 ± 92 836 ± 166 975 ± 125 855 ± 100 773 ± 142
  1. Pairs in bold denote statistically significant differences between VMAT and IMRT.
  2. Pairs in italic denote that the averaged plan parameter is better for IMRT.
  3. ° Not all institutes used objectives to control dose for these structures.