title: [Frameless set-up with ExacTrac®system for stereotactic radiotherapy of brain metastasis: Descriptive study from five French centres].
abstract: OBJECTIVE
  This study aimed to analyse the positioning protocols with the ExacTrac®system, associated with a dedicated linear accelerator such as Novalis®, for stereotactic treatment of brain metastases in several French centres.
  
  
  METHODS
  A survey, including three questions about the prescription of irradiation and twenty-one questions about how the ExacTrac®system is used, was sent to nine French centres owning a dedicated Novalis®accelerator. Five centres have accepted to participate in the study.
  
  
  RESULTS
  All centres checked the positioning before each treatment's bow, with residual mismatch tolerances of 0.5 to 0.7mm for the translations and 0.5 to 1° for the rotations. All centres except one also realised orthogonal planar images of classic incidences to help operators ensure proper isocentre positioning. Prescribed doses were 20Gy in one fraction, 30Gy and 33Gy in three fractions or 34Gy in four fractions, mainly depending on the size of the lesion. Finally, a physician validated the images at the treatment station before starting the irradiation.
  
  
  CONCLUSIONS
  The practices of the different centres concerning the positioning protocols were rather homogeneous, in agreement with the literature data on ExacTrac®system's accuracy, as well as proposed fractionations. The systematic medical validation at the treatment station may, however, be questioned because of the waiting time between the doctor's call and validation itself and because of its usefulness; indeed, corrections by the radiation oncologist are very rare and in some centres, non-existent.
authors.affiliation: Département de radiothérapie, centre de lutte contre le cancer Paul-Strauss, 3, rue de la Porte-de-l'Hôpital, 67065 Strasbourg, France.
authors.forename: T
authors.initials: T
authors.lastname: Ohnleiter
authors.affiliation: Département de radiothérapie, institut de cancérologie de l'Ouest René-Gauducheau, boulevard Jacques-Monod, 44805 Saint-Herblain cedex, France.
authors.forename: M-A
authors.initials: MA
authors.lastname: Mahé
authors.affiliation: Département de radiothérapie, centre Jean-Perrin, 58, rue Montalembert, 63000 Clermont-Ferrand, France.
authors.forename: J
authors.initials: J
authors.lastname: Biau
authors.affiliation: Département de radiothérapie, institut du cancer Courlancy, 38, rue de Courlancy, 51100 Reims, France.
authors.forename: D
authors.initials: D
authors.lastname: Wdowczyk
authors.affiliation: Département de radiothérapie, centre de lutte contre le cancer Paul-Strauss, 3, rue de la Porte-de-l'Hôpital, 67065 Strasbourg, France.
authors.forename: J-B
authors.initials: JB
authors.lastname: Clavier
authors.affiliation: Département de radiothérapie, centre de lutte contre le cancer Paul-Strauss, 3, rue de la Porte-de-l'Hôpital, 67065 Strasbourg, France; Laboratoire EA 3430, Fédération de médecine translationnelle de Strasbourg (FMTS), université de Strasbourg, 67000 Strasbourg, France.
authors.forename: D
authors.initials: D
authors.lastname: Antoni
authors.affiliation: Département de radiothérapie, centre de lutte contre le cancer Paul-Strauss, 3, rue de la Porte-de-l'Hôpital, 67065 Strasbourg, France; Laboratoire EA 3430, Fédération de médecine translationnelle de Strasbourg (FMTS), université de Strasbourg, 67000 Strasbourg, France. Electronic address: GNoel@strasbourg.unicancer.fr.
authors.forename: G
authors.initials: G
authors.lastname: Noël
mesh_terms: D001932:Brain Neoplasms / Q000532:radiotherapy / Q000556:secondary*; D016371:Cranial Irradiation / Q000295:instrumentation*; D005602:France; D019538:Health Care Surveys; D006801:Humans; D038361:Neuronavigation / Q000295:instrumentation*; D010315:Particle Accelerators; D056888:Patient Positioning; D016634:Radiosurgery / Q000295:instrumentation* / Q000379:methods; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D011795:Surveys and Questionnaires
keywords: Brain metastasis; ExacTrac(®); Frameless; Métastase cérébrale; Novalis(®); Radiothérapie en conditions stéréotaxique; Stereotactic irradiation; Traitement sans cadre