title: Technological advancements and error rates in radiation therapy delivery.
abstract: OBJECTIVE
  Technological advances in radiation therapy (RT) delivery have the potential to reduce errors via increased automation and built-in quality assurance (QA) safeguards, yet may also introduce new types of errors. Intensity-modulated RT (IMRT) is an increasingly used technology that is more technically complex than three-dimensional (3D)-conformal RT and conventional RT. We determined the rate of reported errors in RT delivery among IMRT and 3D/conventional RT treatments and characterized the errors associated with the respective techniques to improve existing QA processes.
  
  
  METHODS
  All errors in external beam RT delivery were prospectively recorded via a nonpunitive error-reporting system at Brigham & Women's Hospital/Dana Farber Cancer Institute. Errors are defined as any unplanned deviation from the intended RT treatment and are reviewed during monthly departmental quality improvement meetings. We analyzed all reported errors since the routine use of IMRT in our department, from January 2004 to July 2009. Fisher's exact test was used to determine the association between treatment technique (IMRT vs. 3D/conventional) and specific error types. Effect estimates were computed using logistic regression.
  
  
  RESULTS
  There were 155 errors in RT delivery among 241,546 fractions (0.06%), and none were clinically significant. IMRT was commonly associated with errors in machine parameters (nine of 19 errors) and data entry and interpretation (six of 19 errors). IMRT was associated with a lower rate of reported errors compared with 3D/conventional RT (0.03% vs. 0.07%, p = 0.001) and specifically fewer accessory errors (odds ratio, 0.11; 95% confidence interval, 0.01-0.78) and setup errors (odds ratio, 0.24; 95% confidence interval, 0.08-0.79).
  
  
  CONCLUSIONS
  The rate of errors in RT delivery is low. The types of errors differ significantly between IMRT and 3D/conventional RT, suggesting that QA processes must be uniquely adapted for each technique. There was a lower error rate with IMRT compared with 3D/conventional RT, highlighting the need for sustained vigilance against errors common to more traditional treatment techniques.
authors.affiliation: Harvard Radiation Oncology Program, Boston, MA, USA. dmargalit@partners.org
authors.forename: Danielle N
authors.initials: DN
authors.lastname: Margalit
authors.forename: Yu-Hui
authors.initials: YH
authors.lastname: Chen
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Catalano
authors.forename: Kenneth
authors.initials: K
authors.lastname: Heckman
authors.forename: Todd
authors.initials: T
authors.lastname: Vivenzio
authors.forename: Kristopher
authors.initials: K
authors.lastname: Nissen
authors.forename: Luciant D
authors.initials: LD
authors.lastname: Wolfsberger
authors.forename: Robert A
authors.initials: RA
authors.lastname: Cormack
authors.forename: Peter
authors.initials: P
authors.lastname: Mauch
authors.forename: Andrea K
authors.initials: AK
authors.lastname: Ng
mesh_terms: D001900:Boston; D002173:Cancer Care Facilities / Q000706:statistics & numerical data; D016001:Confidence Intervals; D006801:Humans; D016015:Logistic Models; D019300:Medical Errors / Q000706:statistics & numerical data*; D016017:Odds Ratio; D061214:Patient Safety; D011785:Quality Assurance, Health Care / Q000592:standards; D011786:Quality Control; D011878:Radiotherapy / Q000379:methods* / Q000592:standards; D061106:Radiotherapy Setup Errors / Q000706:statistics & numerical data; D020266:Radiotherapy, Conformal / Q000706:statistics & numerical data; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data