title: Implementation of remote 3-dimensional image guided radiation therapy quality assurance for radiation therapy oncology group clinical trials.
abstract: OBJECTIVE
  To report the process and initial experience of remote credentialing of three-dimensional (3D) image guided radiation therapy (IGRT) as part of the quality assurance (QA) of submitted data for Radiation Therapy Oncology Group (RTOG) clinical trials; and to identify major issues resulting from this process and analyze the review results on patient positioning shifts.
  
  
  METHODS
  Image guided radiation therapy datasets including in-room positioning CT scans and daily shifts applied were submitted through the Image Guided Therapy QA Center from institutions for the IGRT credentialing process, as required by various RTOG trials. A centralized virtual environment is established at the RTOG Core Laboratory, containing analysis tools and database infrastructure for remote review by the Physics Principal Investigators of each protocol. The appropriateness of IGRT technique and volumetric image registration accuracy were evaluated. Registration accuracy was verified by repeat registration with a third-party registration software system. With the accumulated review results, registration differences between those obtained by the Physics Principal Investigators and from the institutions were analyzed for different imaging sites, shift directions, and imaging modalities.
  
  
  RESULTS
  The remote review process was successfully carried out for 87 3D cases (out of 137 total cases, including 2-dimensional and 3D) during 2010. Frequent errors in submitted IGRT data and challenges in the review of image registration for some special cases were identified. Workarounds for these issues were developed. The average differences of registration results between reviewers and institutions ranged between 2 mm and 3 mm. Large discrepancies in the superior-inferior direction were found for megavoltage CT cases, owing to low spatial resolution in this direction for most megavoltage CT cases.
  
  
  CONCLUSIONS
  This first experience indicated that remote review for 3D IGRT as part of QA for RTOG clinical trials is feasible and effective. The magnitude of registration discrepancy between institution and reviewer was presented, and the major issues were investigated to further improve this remote evaluation process.
authors.affiliation: Department of Radiation Oncology, Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Cui
authors.forename: James M
authors.initials: JM
authors.lastname: Galvin
authors.forename: William
authors.initials: W
authors.lastname: Parker
authors.forename: Stephen
authors.initials: S
authors.lastname: Breen
authors.forename: Fang-Fang
authors.initials: FF
authors.lastname: Yin
authors.forename: Jing
authors.initials: J
authors.lastname: Cai
authors.forename: Lech S
authors.initials: LS
authors.lastname: Papiez
authors.forename: X Allen
authors.initials: XA
authors.lastname: Li
authors.forename: Greg
authors.initials: G
authors.lastname: Bednarz
authors.forename: Wenzhou
authors.initials: W
authors.lastname: Chen
authors.forename: Ying
authors.initials: Y
authors.lastname: Xiao
mesh_terms: D002986:Clinical Trials as Topic / Q000592:standards*; D003406:Credentialing / Q000592:standards*; D005240:Feasibility Studies; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000592:standards*; D010380:Peer Review / Q000379:methods*; D011785:Quality Assurance, Health Care / Q000379:methods / Q000592:standards*; D018787:Radiation Oncology / Q000592:standards*; D011880:Radiotherapy Planning, Computer-Assisted / Q000592:standards; D061089:Radiotherapy, Image-Guided / Q000379:methods / Q000592:standards*; D015203:Reproducibility of Results; D012984:Software