title: Helium ions for radiotherapy? Physical and biological verifications of a novel treatment modality.
abstract: OBJECTIVE
  Modern facilities for actively scanned ion beam radiotherapy allow in principle the use of helium beams, which could present specific advantages, especially for pediatric tumors. In order to assess the potential use of these beams for radiotherapy, i.e., to create realistic treatment plans, the authors set up a dedicated (4)He beam model, providing base data for their treatment planning system TRiP98, and they have reported that in this work together with its physical and biological validations.
  
  
  METHODS
  A semiempirical beam model for the physical depth dose deposition and the production of nuclear fragments was developed and introduced in TRiP98. For the biological effect calculations the last version of the local effect model was used. The model predictions were experimentally verified at the HIT facility. The primary beam attenuation and the characteristics of secondary charged particles at various depth in water were investigated using (4)He ion beams of 200 MeV/u. The nuclear charge of secondary fragments was identified using a ΔE/E telescope. 3D absorbed dose distributions were measured with pin point ionization chambers and the biological dosimetry experiments were realized irradiating a Chinese hamster ovary cells stack arranged in an extended target.
  
  
  RESULTS
  The few experimental data available on basic physical processes are reproduced by their beam model. The experimental verification of absorbed dose distributions in extended target volumes yields an overall agreement, with a slight underestimation of the lateral spread. Cell survival along a 4 cm extended target is reproduced with remarkable accuracy.
  
  
  CONCLUSIONS
  The authors presented a simple simulation model for therapeutical (4)He beams which they introduced in TRiP98, and which is validated experimentally by means of physical and biological dosimetries. Thus, it is now possible to perform detailed treatment planning studies with (4)He beams, either exclusively or in combination with other ion modalities.
authors.affiliation: Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Krämer
authors.affiliation: Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt, Germany.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Scifoni
authors.affiliation: Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Schuy
authors.affiliation: Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt, Germany.
authors.forename: Marta
authors.initials: M
authors.lastname: Rovituso
authors.affiliation: Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt, Germany and Trento Institute for Fundamental Physics and Application (TIFPA-INFN), 38123, via Sommarive 14, Trento, Italy.
authors.forename: Walter
authors.initials: W
authors.lastname: Tinganelli
authors.affiliation: Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Maier
authors.affiliation: Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Kaderka
authors.affiliation: Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt, Germany.
authors.forename: Wilma
authors.initials: W
authors.lastname: Kraft-Weyrather
authors.affiliation: Heidelberger Ionenstrahl-Therapiezentrum (HIT), Im Neuenheimer Feld 450, 69120 Heidelberg, Germany and Radioonkologie und Strahlentherapie, Universitätsklinikums Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Brons
authors.affiliation: Heidelberger Ionenstrahl-Therapiezentrum (HIT), Im Neuenheimer Feld 450, 69120 Heidelberg, Germany and Radioonkologie und Strahlentherapie, Universitätsklinikums Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Tessonnier
authors.affiliation: Heidelberger Ionenstrahl-Therapiezentrum (HIT), Im Neuenheimer Feld 450, 69120 Heidelberg, Germany; Radioonkologie und Strahlentherapie, Universitätsklinikums Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany; and Ludwig-Maximilians-Universitaet Muenchen (LMU Munich), Department of Medical Physics, Am Coulombwall 1, 85748 Munich, Germany.
authors.forename: Katia
authors.initials: K
authors.lastname: Parodi
authors.affiliation: Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt, Germany and Trento Institute for Fundamental Physics and Application (TIFPA-INFN), 38123, via Sommarive 14, Trento, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Durante
mesh_terms: D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D063193:Heavy Ion Radiotherapy / Q000379:methods*; D006371:Helium / Q000627:therapeutic use*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted
chemical_list: D006371:Helium