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Table 4 Plan parameters stratified by institute

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

   Institute Technique A B C D E
PTVboost CI95 VMAT 1.39 1.35 1.31 1.43 1.38
IMRT 1.43 1.42 1.37 1.55 1.47
PTVtotal CI95 VMAT 1.51 1.49 1.54 1.45 1.51
IMRT 1.58 1.63 1.70 1.55 1.65
Spinal cord D1% (Gy) VMAT 39.1 45.6 47.7 41.1 43.8
IMRT 39.7 46.7 48.0 42.0 45.5
Brain stem D1% (Gy) VMAT 44.1 45.6 49.4 35.4 44.6
IMRT 42.9 45.8 46.9 40.0 44.4
Parotid gland ipsilateral Dmean (Gy) VMAT 27.6 26.6 33.3 23.2 29.3
IMRT 28.5 28.4 34.2 25.3 39.0
Parotid gland contralateral Dmean (Gy) VMAT 23.9 21.1 23.4 20.6 20.8
IMRT 24.8 22.7 23.6 21.5 23.6
Submandibular gland contralateral Dmean (Gy) VMAT 49.4 58.0 57.4 47.5 52.6
IMRT 49.1 58.6 58.1 51.1 54.3
Oral cavity Dmean (Gy) VMAT 40.0 35.2 41.6 30.7 36.0
IMRT 42.5 40.2 43.6 33.5 37.4
Larynx Dmean (Gy) VMAT 51.4 44.5 49.4 43.5 38.6
IMRT 51.5 46.3 49.1 44.5 40.9
Pharyngeal constrictors° Dmean (Gy) VMAT 52.0 45.0 49.8 43.9 44.7
IMRT 49.0 45.7 48.8 44.2 46.6
Mandible° Dmean (Gy) VMAT 48.8 48.0 50.5 47.6 48.0
IMRT 49.7 49.9 51.1 49.3 51.3
Effective delivery time (min:sec) VMAT 4:51 6:50 -- 5:15 6:41
IMRT 11:47 12:08 -- 15:04 14:00
MUs -- VMAT 600 602 540 774 698
   IMRT 830 670 824 841 975
  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.