title: [Quality control of dose delivered by in vivo dosimetry: can one tolerance be used for all localizations?].
abstract: OBJECTIVE
  In vivo dosimetry measurements are accepted when the difference between measured and calculated dose is under 5%. A statistical analysis has been conducted to determine whether this tolerance matched the clinical practice for the studied localizations: pelvis, thorax, head and neck, breast.
  
  
  METHODS
  The technical characteristics of the detectors were checked before being used in clinical practice. Then an automatic statistical analysis was implemented using the 2450 in vivo dosimetry measurements obtained during 1 year.
  
  
  RESULTS
  The global average is 1.10%, the standard deviation 2.46% and the percentage of out of level measurements 4.09%. By distinguishing the localizations, the 5% tolerance appeared to be too narrow for the breast localization.
  
  
  CONCLUSIONS
  Several investigations were initiated to justify the modification of the tolerance for the breast localization. They highlighted an underestimation of the calculated dose when high beam angles are set: a new correction factor was defined to take account this error. A specific tolerance was also specified for the breast localization.
authors.affiliation: Service de radiothérapie, hôpital européen Georges-Pompidou, Paris, France. stephane.dupont@egp.aphp.fr
authors.forename: S
authors.initials: S
authors.lastname: Dupont
authors.forename: L
authors.initials: L
authors.lastname: Aubignac
authors.forename: S
authors.initials: S
authors.lastname: Dufreneix
authors.forename: C
authors.initials: C
authors.lastname: Briand
authors.forename: F
authors.initials: F
authors.lastname: Jaffre
authors.forename: S
authors.initials: S
authors.lastname: Klotz
authors.forename: F
authors.initials: F
authors.lastname: Lecante
authors.forename: D
authors.initials: D
authors.lastname: Le Du
authors.forename: M
authors.initials: M
authors.lastname: Housset
mesh_terms: D003663:Decision Trees; D006801:Humans; D009369:Neoplasms / Q000532:radiotherapy*; D011786:Quality Control; D011878:Radiotherapy / Q000009:adverse effects; D011879:Radiotherapy Dosage / Q000592:standards*