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. Author manuscript; available in PMC: 2015 Aug 1.
Published in final edited form as: Int J Radiat Oncol Biol Phys. 2014 Jul 8;89(5):1121–1128. doi: 10.1016/j.ijrobp.2014.04.051

Table 1.

Planning dosimetry for the dose-probability PTV plans, and its change from the clinical and ITV-based PTV plans.

Dose-probability PTV plans on mid-
position CT, AVG±SD
Δ in dose-probability PTV plan parameters on mid-
position CT compared to:

Clinical PTV plan on
exhale CT, Δ AVG±SD
ITV-based PTV plan on
exhale CT, Δ AVG±SD
Target dosimetry
  PTV–GTV volume 128±69 cm3 −70±45 cm3 or −35±9 %* −79±41 cm3 or −38±3 %*
  Nominal prescription 40.3±7.6 Gy 3.9±2.8 Gy or 9±5%* 3.7±2.4 Gy, or 9±6%*
  PTVD95 42.6±8.4 Gy 4.5±3.0 Gy or 10±6%* 4.0±2.8 Gy or 9±5%*
Normal liver dosimetry
  Mean dose (excluding GTV) 16.1±3.2 Gy −0.4±1.5 Gy or −3±9% −0.5±1.7 Gy or −3±11 %
  Effective volume, 0.39±0.12 −0.05±0.04* −0.05±0.06*
  Liver NTCP, 2.4±4.0 % −0.5±1.5% −0.5±1.4%
PTV coverage quality
  Volume receiving ≥ prescribed dose 99±1% 1±1%* 0±1%
  RTOG conformality index 1.29±0.15 0.0±0.22 −0.06±0.14
  RTOG coverage quality index†† 0.98±0.05 0.05±0.12 0.03±0.11
  RTOG homogeneity index# 1.17±0.06 −0.04±0.05* −0.03±0.05

Abbreviations: AVG=average; CT=computed tomography; GTV=gross tumor volume; ITV=internal target volume; NTCP=normal tissue complication probability; PTV=planning target volume; PTVD95=dose to 95% of the PTV; RTOG=Radiation Therapy Oncology Group; SD=standard deviation.

Notes:

*

p<0.01 two-tailed paired Student’s T-test;

calculated as per Kutcher et al.(19);

calculated with Lyman-linear quadratic model corrected for the dose/fraction (α/β=2.5 Gy)(14);

ratio of nominal prescription isodose volume/PTV;

††

ratio of min PTV dose to 0.5cm3/nominal prescription dose;

#

ratio b of max PTV dose to 0.5cm3/nominal prescription dose.