title: Technical Note: Introduction of variance component analysis to setup error analysis in radiotherapy.
abstract: OBJECTIVE
  The purpose of this technical note is to introduce variance component analysis to the estimation of systematic and random components in setup error of radiotherapy.
  
  
  METHODS
  Balanced data according to the one-factor random effect model were assumed.
  
  
  RESULTS
  Analysis-of-variance (anova)-based computation was applied to estimate the values and their confidence intervals (CIs) for systematic and random errors and the population mean of setup errors. The conventional method overestimates systematic error, especially in hypofractionated settings. The CI for systematic error becomes much wider than that for random error. The anova-based estimation can be extended to a multifactor model considering multiple causes of setup errors (e.g., interpatient, interfraction, and intrafraction).
  
  
  CONCLUSIONS
  Variance component analysis may lead to novel applications to setup error analysis in radiotherapy.
authors: Department of Radiation Oncology and Image-applied Therapy, Kyoto University, 54 Shogoin-Kawaharacho, Sakyo, Kyoto 606-8507, Japan.
authors: Yukinori
authors: Y
authors: Matsuo
authors: Department of Radiation Oncology and Image-applied Therapy, Kyoto University, 54 Shogoin-Kawaharacho, Sakyo, Kyoto 606-8507, Japan.
authors: Mitsuhiro
authors: M
authors: Nakamura
authors: Department of Radiation Oncology and Image-applied Therapy, Kyoto University, 54 Shogoin-Kawaharacho, Sakyo, Kyoto 606-8507, Japan.
authors: Takashi
authors: T
authors: Mizowaki
authors: Department of Radiation Oncology and Image-applied Therapy, Kyoto University, 54 Shogoin-Kawaharacho, Sakyo, Kyoto 606-8507, Japan.
authors: Masahiro
authors: M
authors: Hiraoka
mesh_terms: D000704:Analysis of Variance; D061106:Radiotherapy Setup Errors / Q000517:prevention & control