title: Craniospinal radiotherapy in children: Electron- or photon-based technique of spinal irradiation.
abstract: BACKGROUND
  The prone position and electron-based technique for craniospinal irradiation (CSI) have been standard in our department for many years. But this immobilization is difficult for the anaesthesiologist to gain airway access. The increasing number of children treated under anaesthesia led us to reconsider our technique.
  
  
  OBJECTIVE
  The purpose of this study is to report our new photon-based technique for CSI which could be applied in both the supine and the prone position and to compare this technique with our electron-based technique.
  
  
  METHODS
  Between November 2007 and May 2008, 11 children with brain tumours were treated in the prone position with CSI. For 9 patients two treatment plans were created: the first one using photons and the second one using electron beams for spinal irradiation. We prepared seven 3D-conformal photon plans and four forward planned segmented field plans. We compared 20 treatment plans in terms of target dose homogeneity and sparing of organs at risk.
  
  
  RESULTS
  In segmented field plans better dose homogeneity in the thecal sac volume was achieved than in electron-based plans. Regarding doses in organs at risk, in photon-based plans we obtained a lower dose in the thyroid but a higher one in the heart and liver.
  
  
  CONCLUSIONS
  Our technique can be applied in both the supine and prone position and it seems to be more feasible and precise than the electron technique. However, more homogeneous target coverage and higher precision of dose delivery for photons are obtained at the cost of slightly higher doses to the heart and liver.
authors.affiliation: Department of Radiotherapy, Maria Skłodowska Curie Memorial Cancer Centre - Institute, Wawelska 15, 00-973 Warsaw, Poland.
authors.forename: Marzanna
authors.initials: M
authors.lastname: Chojnacka
authors.affiliation: Department of Radiotherapy, Maria Skłodowska Curie Memorial Cancer Centre - Institute, Wawelska 15, 00-973 Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Skowrońska-Gardas
authors.affiliation: Department of Medical Physics, Maria Skłodowska Curie Memorial Cancer Centre - Institute, Wawelska 15, 00-973 Warsaw, Poland.
authors.forename: Marzena
authors.initials: M
authors.lastname: Morawska-Kaczyńska
authors.affiliation: Department of Medical Physics, Maria Skłodowska Curie Memorial Cancer Centre - Institute, Wawelska 15, 00-973 Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Zygmuntowicz-Piętka
authors.affiliation: Department of Radiotherapy, Maria Skłodowska Curie Memorial Cancer Centre - Institute, Wawelska 15, 00-973 Warsaw, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Pędziwiatr
authors.affiliation: Department of Medical Physics, Maria Skłodowska Curie Memorial Cancer Centre - Institute, Wawelska 15, 00-973 Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Semaniak
keywords: Craniospinal irradiation; Late toxicity; Supine position