title: Practice patterns of photon and proton pediatric image guided radiation treatment: results from an International Pediatric Research consortium.
abstract: OBJECTIVE
  Image guided radiation therapy (IGRT) has become common practice for both photon and proton radiation therapy, but there is little consensus regarding its application in the pediatric population. We evaluated clinical patterns of pediatric IGRT practice through an international pediatrics consortium comprised of institutions using either photon or proton radiation therapy.
  
  
  METHODS
  Seven international institutions with dedicated pediatric expertise completed a 53-item survey evaluating patterns of IGRT use in definitive radiation therapy for patients ≤21 years old. Two institutions use proton therapy for children and all others use IG photon therapy. Descriptive statistics including frequencies of IGRT use and means and standard deviations for planning target volume (PTV) margins by institution and treatment site were calculated.
  
  
  RESULTS
  Approximately 750 pediatric patients were treated annually across the 7 institutions. IGRT was used in tumors of the central nervous system (98%), abdomen or pelvis (73%), head and neck (100%), lung (83%), and liver (69%). Photon institutions used kV cone beam computed tomography and kV- and MV-based planar imaging for IGRT, and all proton institutions used kV-based planar imaging; 57% of photon institutions used a specialized pediatric protocol for IGRT that delivers lower dose than standard adult protocols. Immobilization techniques varied by treatment site and institution. IGRT was utilized daily in 45% and weekly in 35% of cases. The PTV margin with use of IGRT ranged from 2 cm to 1 cm across treatment sites and institution.
  
  
  CONCLUSIONS
  Use of IGRT in children was prevalent at all consortium institutions. There was treatment site-specific variability in IGRT use and technique across institutions, although practices varied less at proton facilities. Despite use of IGRT, there was no consensus of optimum PTV margin by treatment site. Given the desire to restrict any additional radiation exposure in children to instances where the exposure is associated with measureable benefit, prospective studies are warranted to optimize IGRT protocols by modality and treatment site.
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland.
authors.forename: Sara R
authors.initials: SR
authors.lastname: Alcorn
authors.affiliation: Department of Radiation, Grupo de Apoio ao Adolescente e à Criança com Câncer, São Paulo, Brazil.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Chen
authors.affiliation: Département de Radiothérapie, Centre de Lutte Contre Le Cancer Léon Bérard, Lyon, France.
authors.forename: Line
authors.initials: L
authors.lastname: Claude
authors.affiliation: Department of Radiation Oncology, Universität Klinik Für Strahlentherapie und Strahlenbiologie, Vienna, Austria.
authors.forename: Karin
authors.initials: K
authors.lastname: Dieckmann
authors.affiliation: Department of Radiation Oncology, University of Washington, Seattle, Washington.
authors.forename: Ralph P
authors.initials: RP
authors.lastname: Ermoian
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland; Department of Radiation Oncology, University of Washington, Seattle, Washington.
authors.forename: Eric C
authors.initials: EC
authors.lastname: Ford
authors.affiliation: Département de Radiothérapie, Centre de Lutte Contre Le Cancer Léon Bérard, Lyon, France.
authors.forename: Claude
authors.initials: C
authors.lastname: Malet
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Shannon M
authors.initials: SM
authors.lastname: MacDonald
authors.affiliation: Department of Radiotherapy, Federal Scientific Clinical Center of Children's Hematology, Oncology and Immunology, Moscow, Russia.
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Nechesnyuk
authors.affiliation: Department of Oncology, Uppsala University Hospital, Uppsala, Sweden.
authors.forename: Kristina
authors.initials: K
authors.lastname: Nilsson
authors.affiliation: Department of Radiation Oncology Centro Infantil Boldrini, São Paulo e Região, Brazil.
authors.forename: Rosangela C
authors.initials: RC
authors.lastname: Villar
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Brian A
authors.initials: BA
authors.lastname: Winey
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland; Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Erik J
authors.initials: EJ
authors.lastname: Tryggestad
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland. Electronic address: sterezak@jhmi.edu.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Terezakis
mesh_terms: D000328:Adult; D002648:Child; D054893:Cone-Beam Computed Tomography; D005500:Follow-Up Studies; D006801:Humans; D007390:International Agencies; D009369:Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D017785:Photons / Q000627:therapeutic use*; D010818:Practice Patterns, Physicians'; D011379:Prognosis; D061766:Proton Therapy; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D061089:Radiotherapy, Image-Guided; D050397:Radiotherapy, Intensity-Modulated; D011522:Protons
chemical_list: D011522:Protons