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Table 6 Dosimetric comparisons of plans with pre-correction margins and plans with post-correction margins for OARs in 40 NPC patients

From: Dosimetric benefit to organs at risk following margin reductions in nasopharyngeal carcinoma treated with intensity-modulated radiation therapy

Organ Dose index Plans with pre-correction margins Plans with post-correction margins Difference P value
BrainStem_PRV D1% (Gy) 56.93 ± 5.48 55.62 ± 5.23 1.31 ± 1.08 <0.001
SpinalCord_PRV D1% (Gy) 37.95 ± 3.81 36.91 ± 3.45 1.04 ± 1.41 <0.001
OpticNerve_L_PRV D1% (Gy) 51.89 ± 15.01 50.97 ± 14.48 0.91 ± 2.20 0.012
OpticNerve_R_PRV D1% (Gy) 51.58 ± 16.49 50.90 ± 16.57 0.68 ± 2.81 0.134
Chiasm_PRV D1% (Gy) 58.84 ± 13.35 58.63 ± 12.90 0.21 ± 2.36 0.578
Lens_L Dmax (Gy) 5.85 ± 1.81 5.81 ± 1.82 0.04 ± 0.23 0.327
Lens_R Dmax (Gy) 5.88 ± 1.86 5.84 ± 1.84 0.04 ± 0.21 0.223
Parotid_L Dmean (Gy) 37.31 ± 4.29 34.66 ± 4.17 2.65 ± 1.33 <0.001
  V30Gy (%) 60.81 ± 15.83 53.35 ± 15.39 7.46 ± 7.18 <0.001
Parotid_R Dmean (Gy) 37.31 ± 4.08 34.44 ± 4.20 2.87 ± 1.42 <0.001
  V30Gy (%) 61.16 ± 15.25 52.27 ± 15.92 8.89 ± 8.51 <0.001
TemporalLobe_L D1% (Gy) 63.67 ± 6.94 62.73 ± 7.47 0.94 ± 2.17 0.009
TemporalLobe_R D1% (Gy) 64.58 ± 6.24 63.14 ± 6.35 1.44 ± 2.03 <0.001
Mandible_L D1cc (Gy) 60.24 ± 3.43 58.56 ± 4.36 1.67 ± 2.10 <0.001
Mandible_R D1cc (Gy) 60.28 ± 4.56 58.28 ± 5.18 2.00 ± 1.83 <0.001
TMjoint_L D1cc (Gy) 44.67 ± 10.59 42.16 ± 10.79 2.51 ± 4.24 0.001
TMjoint_R D1cc (Gy) 45.46 ± 12.14 43.40 ± 10.99 2.06 ± 3.25 <0.001
Ear_Inner_L Dmean (Gy) 49.36 ± 7.98 47.69 ± 7.67 1.67 ± 1.61 <0.001
Ear_Inner_R Dmean (Gy) 49.86 ± 8.42 48.00 ± 8.17 1.87 ± 2.22 <0.001
Larynx Dmean (Gy) 47.09 ± 2.57 45.98 ± 2.52 1.11 ± 1.46 <0.001
  1. All data are presented as mean ± SD of 40 patients. V30Gy, percentage volume receiving at least 30 Gy. Other abbreviations as in Tables 3 and 4.