title: Static and rotational intensity modulated techniques for head-neck cancer radiotherapy: a planning comparison.
abstract: OBJECTIVE
  To compare helical Tomotherapy (HT), two volumetric-modulated arc techniques and conventional fixed-field intensity modulated techniques (S-IMRT) for head-neck (HN) cancers.
  
  
  METHODS
  Eighteen HN patients were considered. Four treatment plans were generated for each patient: HT, S-IMRT optimised with Eclipse treatment planning system and two volumetric techniques using Elekta-Oncentra approach (VMAT) and Varian-RapidArc (RA), using two full arcs. All techniques were optimised to simultaneously deliver 66Gy to PTV1 (GTV and enlarged nodes) and 54Gy to PTV2 (subclinical and electively treated nodes). Comparisons were assessed on several dosimetric parameters and, secondarily, on planned MUs and delivery time.
  
  
  RESULTS
  Concerning PTV coverage, significantly better results were found for HT and RA. HT significantly improved the target coverage both compared to S-IMRT and VMAT. No significant differences were found between S-IMRT and volumetric techniques in terms of dose homogeneity. For OARs, all the techniques were able to satisfy all hard constraints; significantly better results were found for HT, especially in the intermediate dose range (15-30 Gy). S-IMRT reached a significantly better OARs sparing with respect to VMAT and RA. No significant differences were found for body mean dose, excepting higher values of V5-V10 for HT. A reduction of planned MUs and delivery treatment time was found with volumetric techniques.
  
  
  CONCLUSIONS
  The objectives of satisfying target coverage and sparing of critical structures were reached with all techniques. S-IMRT techniques were found more advantageous compared to RA and VMAT for OARs sparing. HT reached the best overall treatment plan quality.
authors.affiliation: Medical Physics Department, San Raffaele Scientific Institute, Milano, Italy. Electronic address: broggi.sara@hsr.it.
authors.forename: Sara
authors.initials: S
authors.lastname: Broggi
authors.affiliation: Medical Physics Department, San Raffaele Scientific Institute, Milano, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Perna
authors.affiliation: Medical Physics Department, Ospedale A. Manzoni, Lecco, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Bonsignore
authors.affiliation: Medical Physics Department, San Raffaele Scientific Institute, Milano, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Rinaldin
authors.affiliation: Medical Physics Department, San Raffaele Scientific Institute, Milano, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Fiorino
authors.affiliation: Radiotherapy Department, San Raffaele Scientific Institute, Milano, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Chiara
authors.affiliation: Medical Physics Department, Ospedale A. Manzoni, Lecco, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Frigerio
authors.affiliation: Medical Physics Department, Ospedale A. Manzoni, Lecco, Italy.
authors.forename: Ivana
authors.initials: I
authors.lastname: Butti
authors.affiliation: Medical Physics Department, Ospedale A. Manzoni, Lecco, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Sangalli
authors.affiliation: Radiotherapy Department, San Raffaele Scientific Institute, Milano, Italy.
authors.forename: Italo
authors.initials: I
authors.lastname: Dell'Oca
authors.affiliation: Radiotherapy Department, San Raffaele Scientific Institute, Milano, Italy.
authors.forename: Nadia
authors.initials: N
authors.lastname: Di Muzio
authors.affiliation: Medical Physics Department, San Raffaele Scientific Institute, Milano, Italy.
authors.forename: Giovanni Mauro
authors.initials: GM
authors.lastname: Cattaneo
authors.affiliation: Medical Physics Department, Ospedale A. Manzoni, Lecco, Italy.
authors.forename: Fausto
authors.initials: F
authors.lastname: Declich
mesh_terms: D000465:Algorithms; D001921:Brain / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D004947:Esophagus / Q000528:radiation effects; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D007830:Larynx / Q000528:radiation effects; D008334:Mandible / Q000528:radiation effects; D010306:Parotid Gland / Q000528:radiation effects; D011874:Radiometry / Q000379:methods; D011878:Radiotherapy / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D015203:Reproducibility of Results; D013116:Spinal Cord / Q000528:radiation effects; D013961:Thyroid Gland / Q000528:radiation effects
keywords: Dosimetrical comparison; Head and neck cancer; IMRT; Volumetric arc techniques