title: Quantification of renal and diaphragmatic interfractional motion in pediatric image-guided radiation therapy: A multicenter study.
abstract: OBJECTIVE
  To quantify renal and diaphragmatic interfractional motion in order to estimate systematic and random errors, and to investigate the correlation between interfractional motion and patient-specific factors.
  
  
  METHODS
  We used 527 retrospective abdominal-thoracic cone beam CT scans of 39 childhood cancer patients (<18 years) to quantify renal motion relative to bony anatomy in the left-right (LR), cranio-caudal (CC) and anterior-posterior (AP) directions, and diaphragmatic motion in the CC direction only. Interfractional motion was quantified by distributions of systematic and random errors in each direction (standard deviations Σ and σ, respectively). Also, correlation between organ motion and height was analyzed.
  
  
  RESULTS
  Inter-patient organ motion varied widely, with the largest movements in the CC direction. Values of Σ in LR, CC, and AP directions were 1.1, 3.8, 2.1 mm for the right, and 1.3, 3.0, 1.5 mm for the left kidney, respectively. The σ in these three directions was 1.1, 3.1, 1.7 mm for the right, and 1.2, 2.9, 2.1 mm for the left kidney, respectively. For the diaphragm we estimated Σ=5.2 mm and σ=4.0 mm. No correlations were found between organ motion and height.
  
  
  CONCLUSIONS
  The large inter-patient organ motion variations and the lack of correlation between motion and patient-related factors, suggest that individualized margin approaches might be required.
authors.affiliation: Academic Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands. Electronic address: s.c.huijskens@amc.uva.nl.
authors.forename: Sophie C
authors.initials: SC
authors.lastname: Huijskens
authors.affiliation: Academic Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands.
authors.forename: Irma W E M
authors.initials: IW
authors.lastname: van Dijk
authors.affiliation: Academic Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands.
authors.forename: Rianne
authors.initials: R
authors.lastname: de Jong
authors.affiliation: Academic Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands.
authors.forename: Jorrit
authors.initials: J
authors.lastname: Visser
authors.affiliation: Academic Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands.
authors.forename: Raquel Dávila
authors.initials: RD
authors.lastname: Fajardo
authors.affiliation: Academic Medical Center/Emma Children's Hospital, Department of Pediatric Oncology, Amsterdam, The Netherlands.
authors.forename: Cécile M
authors.initials: CM
authors.lastname: Ronckers
authors.affiliation: Radboud University Medical Center, Department of Radiation Oncology, Nijmegen, The Netherlands.
authors.forename: Geert O R J
authors.initials: GO
authors.lastname: Janssens
authors.affiliation: University of Groningen, Department of Radiation Oncology, The Netherlands.
authors.forename: John H
authors.initials: JH
authors.lastname: Maduro
authors.affiliation: Academic Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands.
authors.forename: Coen R N
authors.initials: CR
authors.lastname: Rasch
authors.affiliation: Academic Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands.
authors.forename: Tanja
authors.initials: T
authors.lastname: Alderliesten
authors.affiliation: Academic Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands.
authors.forename: Arjan
authors.initials: A
authors.lastname: Bel
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D003951:Diagnostic Errors; D003964:Diaphragm / Q000502:physiology*; D005260:Female; D006801:Humans; D007223:Infant; D007668:Kidney / Q000502:physiology*; D008297:Male; D009068:Movement / Q000502:physiology; D009369:Neoplasms / Q000532:radiotherapy; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D061089:Radiotherapy, Image-Guided / Q000379:methods*; D012189:Retrospective Studies
keywords: IGRT; Organ motion; Pediatric RT; Systematic and random errors