title: Prospective study on dosimetric comparison of helical tomotherapy and 3DCRT for craniospinal irradiation - A single institution experience.
abstract: OBJECTIVE
  This prospective study aims to assess feasibility of helical tomotherapy (HT) for craniospinal irradiation (CSI) and perform dosimetric comparison of treatment plans for both HT and 3D conformal radiotherapy (3DCRT).
  
  
  BACKGROUND
  CSI is a challenging procedure. Large PTV size requires field matching due to technical limitations of standard linear accelerators, which cannot irradiate such volumes as a single field. HT could help to avoid these limitations as irradiation of long fields is possible without field matching.
  
  
  METHODS
  Three adults were enrolled from 2009 to 2010. All patients received radiochemotherapy. Treatment plans in prone position for 3DCRT and in supine position for HT were generated. The superior plan was used for patients' irradiation. Plans were compared with the application of DVH, Dx parameters - where x represents a percentage of the structure volume receiving a normalized dose and homogeneity index (HI).
  
  
  RESULTS
  All patients received HT irradiation. The treatment was well tolerated. The HT plans resulted in a better dose coverage and uniformity in the PTV: HI were 5.4, 7.8, 6.8 for HT vs. 10.3, 6.6, 10.4 for 3DCRT. For most organs at risk (OARs), the D(V80) was higher for HT than for 3DCRT, whereas D(V5) was lower for HT.
  
  
  CONCLUSIONS
  HT is feasible for CSI, and in comparison with 3DCRT it improves PTV coverage. HT reduces high dose volumes of OARs, but larger volumes of normal tissue receive low radiation dose. HT requires further study to establish correlations between dosimetrical findings and clinical outcomes, especially with regard to late sequelae of treatment.
authors: Radiotherapy Department II, Greater Poland Cancer Centre, Poznań, Poland.
authors: Anna
authors: A
authors: Bandurska-Luque
authors: Department of Electroradiology, University of Medical Sciences, Poznań, Poland ; Medical Physics Department, Greater Poland Cancer Centre, Poznań, Poland.
authors: Tomasz
authors: T
authors: Piotrowski
authors: Department of Electroradiology, University of Medical Sciences, Poznań, Poland ; Medical Physics Department, Greater Poland Cancer Centre, Poznań, Poland.
authors: Agnieszka
authors: A
authors: Skrobała
authors: Medical Physics Department, Greater Poland Cancer Centre, Poznań, Poland.
authors: Adam
authors: A
authors: Ryczkowski
authors: Radiotherapy Department III, Greater Poland Cancer Centre, Poznań, Poland.
authors: Krystyna
authors: K
authors: Adamska
authors: Department of Electroradiology, University of Medical Sciences, Poznań, Poland ; Radiotherapy Department II, Greater Poland Cancer Centre, Poznań, Poland.
authors: Joanna
authors: J
authors: Kaźmierska
keywords: Craniospinal irradiation; Dosimetric comparison; Helical tomotherapy