title: Initial experience of hypofractionated radiation retreatment with true beam and flattening filter free beam in selected case reports of recurrent nasopharyngeal carcinoma.
abstract: OBJECTIVE
  To show our preliminary experience in using TrueBeam with RapidArc technology and FFF beam for stereotactic re-irradiation of nasopharyngeal carcinoma.
  
  
  BACKGROUND
  Thanks to new advanced techniques, as well as intensity modulated radiation therapy, it is possible to approach head and neck recurrences in selected patients. Volumetric Modulated Arc Therapy (VMAT) in its RapidArc(®) format, permits to reduce significantly the time to deliver complex intensity modulated plans, allowing to treat hypofractionated regimes within a few minutes. With TrueBeam it is possible to perform photon beams without usage of the flattening filter. It seems possible to expect a reduction of out-of-field dose when flattening filter free (FFF) beams are used. While research into the physics domain for FFF beams is increasing, there are very few clinical data where FFF beams are applied in clinical practice.
  
  
  METHODS
  We present here the cases of 4 patients with local or regional recurrence of nasopharyngeal carcinoma. All patients were treated using TrueBeam with RapidArc technology and FFF beam for stereotactic hypofractionated re-irradiation.
  
  
  RESULTS
  All patients concluded SBRT and showed good tolerability. During follow-up, complete response at imaging evaluation (PET and/or MRI) for all treated patients was documented.
  
  
  CONCLUSIONS
  Our preliminary experience using TrueBeam with RapidArc technology and FFF beam for stereotactic hypofractionated re-irradiation of nasopharyngeal carcinoma was safe and effective in all 4 treated patients. Longer follow-up and a larger population of study is needed to confirm these promising results.
authors.affiliation: Radiotherapy and Radiosurgery Department, Humanitas Cancer Center, Istituto Clinico Humanitas, Via Manzoni 56, 20089 Rozzano, Milan, Italy.
authors.forename: Filippo
authors.initials: F
authors.lastname: Alongi
authors.affiliation: Radiotherapy and Radiosurgery Department, Humanitas Cancer Center, Istituto Clinico Humanitas, Via Manzoni 56, 20089 Rozzano, Milan, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Clerici
authors.affiliation: Radiotherapy and Radiosurgery Department, Humanitas Cancer Center, Istituto Clinico Humanitas, Via Manzoni 56, 20089 Rozzano, Milan, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Pentimalli
authors.affiliation: Radiotherapy and Radiosurgery Department, Humanitas Cancer Center, Istituto Clinico Humanitas, Via Manzoni 56, 20089 Rozzano, Milan, Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Mancosu
authors.affiliation: Radiotherapy and Radiosurgery Department, Humanitas Cancer Center, Istituto Clinico Humanitas, Via Manzoni 56, 20089 Rozzano, Milan, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Scorsetti
keywords: Flattening filter free beam; Hypofractionation; Nasopharyngeal carcinoma; Reirradiation