title: Daily orthogonal kilovoltage imaging using a gantry-mounted on-board imaging system results in a reduction in radiation therapy delivery errors.
abstract: OBJECTIVE
  To determine whether the use of routine image guided radiation therapy (IGRT) using pretreatment on-board imaging (OBI) with orthogonal kilovoltage X-rays reduces treatment delivery errors.
  
  
  METHODS
  A retrospective review of documented treatment delivery errors from 2003 to 2009 was performed. Following implementation of IGRT in 2007, patients received daily OBI with orthogonal kV X-rays prior to treatment. The frequency of errors in the pre- and post-IGRT time frames was compared. Treatment errors (TEs) were classified as IGRT-preventable or non-IGRT-preventable.
  
  
  RESULTS
  A total of 71,260 treatment fractions were delivered to 2764 patients. A total of 135 (0.19%) TEs occurred in 39 (1.4%) patients (3.2% in 2003, 1.1% in 2004, 2.5% in 2005, 2% in 2006, 0.86% in 2007, 0.24% in 2008, and 0.22% in 2009). In 2007, the TE rate decreased by >50% and has remained low (P = .00007, compared to before 2007). Errors were classified as being potentially preventable with IGRT (e.g., incorrect site, patient, or isocenter) vs. not. No patients had any IGRT-preventable TEs from 2007 to 2009, whereas there were 9 from 2003 to 2006 (1 in 2003, 2 in 2004, 2 in 2005, and 4 in 2006; P = .0058) before the implementation of IGRT.
  
  
  CONCLUSIONS
  IGRT implementation has a patient safety benefit with a significant reduction in treatment delivery errors. As such, we recommend the use of IGRT in routine practice to complement existing quality assurance measures.
authors.affiliation: Department of Radiation Oncology, Boston Medical Center and Boston University School of Medicine, Boston, MA 02118, USA. gregory.russo@bmc.org
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Russo
authors.forename: Muhammad M
authors.initials: MM
authors.lastname: Qureshi
authors.forename: Minh-Tam
authors.initials: MT
authors.lastname: Truong
authors.forename: Ariel E
authors.initials: AE
authors.lastname: Hirsch
authors.forename: Lawrence
authors.initials: L
authors.lastname: Orlina
authors.forename: Harry
authors.initials: H
authors.lastname: Bohrs
authors.forename: Pauline
authors.initials: P
authors.lastname: Clancy
authors.forename: John
authors.initials: J
authors.lastname: Willins
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Kachnic
mesh_terms: D004867:Equipment Design; D006801:Humans; D019300:Medical Errors / Q000145:classification / Q000517:prevention & control* / Q000706:statistics & numerical data; D010315:Particle Accelerators; D010355:Patient Identification Systems; D061214:Patient Safety; D058996:Quality Improvement; D011829:Radiation Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D061106:Radiotherapy Setup Errors / Q000517:prevention & control; D061089:Radiotherapy, Image-Guided / Q000295:instrumentation / Q000379:methods*; D012189:Retrospective Studies