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Table 3 Changes in tumor volume and dose intensity based on dose volume histogram before and after surgical spacer placement

From: Surgical spacer placement for proton radiotherapy in locally advanced pancreatic body and tail cancers: initial clinical results

  Parameter Preoperative
Mean value
Postoperative
Mean value
T-test
Tumor Volume (ml) 34.1 45.9 0.023
GTV V95% (%) 49.7 71.9 0.001
  V60(Gy [RBE]) (%) 66.4 84.7  < 0.001
  D95% (Gy [RBE]) 49.7 53.7  < 0.001
  Dmean (Gy [RBE]) 61.5 64.5  < 0.001
  Dmin (Gy [RBE]) 46.2 48.1 0.019
CTV V95% (%) 50.8 66.7 0.004
  V60(Gy [RBE]) (%) 64.1 78.4 0.002
  D95% (Gy [RBE]) 48.0 50.1 0.005
  Dmean (Gy [RBE]) 61.4 63.6 0.003
  Dmin (Gy [RBE]) 44.6 45.2 0.030
PTV V95% (%) 39.3 52.8 0.005
  V60(Gy [RBE]) (%) 51.1 65.2 0.002
  D95% (Gy [RBE]) 45.3 45.9 0.021
  Dmean (Gy [RBE]) 48.7 61.1 0.002
  Dmin (Gy [RBE]) 37.9 37.1 0.451
Stomach D0.5 cc (Gy [RBE]) 46.6 45.8 0.190
  V48(Gy [RBE]) (cc) 0.211 0.16 0.144
  V40(Gy [RBE]) (cc) 22.3 12.2 0.018
  V30(Gy [RBE]) (cc) 40.0 27.5 0.038
Small intestine D0.5 cc (Gy [RBE]) 47.5 47.1 0.239
  V48(Gy [RBE]) (cc) 0.331 0.3 0.337
  V40(Gy [RBE]) (cc) 11.9 9.99 0.031
  V30(Gy [RBE]) (cc) 21.1 16.8 0.020
Large intestine D0.5 cc (Gy [RBE]) 20.7 14.0 0.228
  V48(Gy [RBE]) (cc) 0.068 0.0008 0.101
  V40(Gy [RBE]) (cc) 4.23 0.12 0.088
  V30(Gy [RBE]) (cc) 8.29 0.4 0.089
  1. GTV gross tumor volume, CTV clinical target volume, PTV planning target volume, RBE relative biological effectiveness, V95% the volume that 95% of the treatment planning dose is irradiated, V60 the percentage of volume irradiated more than 60 Gy (RBE), D95% a dose intensity covering 95% of the target volume, Dmean, the average dose of the target volume, Dmin the minimum dose of the target volume; D0.5 cc, maximum dose at which more than 0.5 cc of an organ volume is irradiated; V48, V40 and V30, the volume irradiated by more than 48, 40 and 30 Gy (RBE), respectively