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Table 2 Quantitative parameters measuring quality: definition of indices

From: Quality assurance of radiotherapy in the ongoing EORTC 22042–26042 trial for atypical and malignant meningioma: results from the dummy runs and prospective individual case Reviews

Parameter [ref] Definition Optimal Value Acceptable Minor Violation Major Violation
RTOG Conformity Index (CI) [11] V pi / V T 1.0 1.0 – 2.0 ≥ 0.9-1.0 or > 2.0-2.5 < 0.9 or >2.5
Target Coverage (TC) [12] V T,pi / V T 1.0 ≥0.95 – 1.0 0.90 - 0.95 < 0.90
Homogeneity Index (HI)* [13] (D 2 %- D 98 %) / D 50 % 0.0 0.0 - 0.12 0.12 - 0.2 > 0.2
  1. *HI minor and major deviations defined according to protocol deviation parameters for dose conformity and PTV D 2 %.
  2. Abbreviations: Vpi, Prescription Isodose Volume; VT, Volume Target; VT,pi, 95% isodose volume within the target; D2%, D50%, D98%, Dose received by 2, 50 and 98 percent of the PTV, respectively.