title: A dosimetric comparison between CyberKnife and tomotherapy treatment plans for single brain metastasis.
abstract: OBJECTIVE
  Radiosurgery (RS) is a well-established treatment in selected patients with brain metastasis. The aim of this study is to compare the differences between CyberKnife (CK) and TomoTherapy (HT) treatment plans of RS of single brain metastasis (BM) to define when HT should be used in cases beyond Cyberknife-when both systems are readily available for the radiation oncologist.
  
  
  METHODS
  Nineteen patients with single brain metastasis treated with CK were re-planned for radiosurgery using TomoTherapy Hi-ART system. Two planning approaches have been used for TomoTherapy plans: the classical one (HT) and the improved conformity (icHT) that produces dose distributions more similar to those of RS plans. PTV coverage, Conformity Index (CI), Paddick Conformity Index (nCI), Homogeneity Index (HI), Gradient Index (GI), and beam on time of CK, HT, and icHT plans were evaluated and compared.
  
  
  RESULTS
  A good coverage was found for CK, HT, and icHT plans. A difference between mean HI of CK and icHT plans was observed (p = 0.007). Better dose gradients compared to both icHT and HT modalities were observed in CK plans. icHT modality showed improved mean CI respect to HT modality, similar to that obtained in CK plans.
  
  
  CONCLUSIONS
  CK plans show higher conformity and lower GI than icHT and HT plans. TomoTherapy demonstrates the advantage of being a device capable to reach different clinical objectives depending on the different planning modality employed. CyberKnife and TomoTherapy are both optimal RS devices, the choice to use one over another has to be clinically guided.
authors.affiliation: Radiotherapy Unit, Azienda Ospedaliero Universitaria Careggi, University of Florence, Largo Brambilla 3, 50141, Florence, Italy. daniela.greto@gmail.com.
authors.forename: Daniela
authors.initials: D
authors.lastname: Greto
authors.affiliation: Medical Physics Unit, Azienda Ospedaliero Universitaria Careggi, University of Florence, Florence, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Pallotta
authors.affiliation: Medical Physics Unit, I.F.C.A., Florence, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Masi
authors.affiliation: Medical Physics Unit, Azienda Ospedaliero Universitaria Careggi, University of Florence, Florence, Italy.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Talamonti
authors.affiliation: Medical Physics Unit, Azienda Ospedaliero Universitaria Careggi, University of Florence, Florence, Italy.
authors.forename: Livia
authors.initials: L
authors.lastname: Marrazzo
authors.affiliation: Medical Physics Unit, I.F.C.A., Florence, Italy.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Doro
authors.affiliation: Molecular and Nutritional Epidemiology Unit, ISPO (Cancer Research and Prevention Institute), Florence, Italy.
authors.forename: Calogero
authors.initials: C
authors.lastname: Saieva
authors.affiliation: Radiotherapy Unit, Azienda Ospedaliero Universitaria Careggi, University of Florence, Largo Brambilla 3, 50141, Florence, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Scoccianti
authors.affiliation: Radiotherapy Unit, Azienda Ospedaliero Universitaria Careggi, University of Florence, Largo Brambilla 3, 50141, Florence, Italy.
authors.forename: Isacco
authors.initials: I
authors.lastname: Desideri
authors.affiliation: Radiotherapy Unit, Azienda Ospedaliero Universitaria Careggi, University of Florence, Largo Brambilla 3, 50141, Florence, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Livi
mesh_terms: D001932:Brain Neoplasms / Q000556:secondary* / Q000628:therapy*; D006801:Humans; D059146:Metastasectomy / Q000379:methods*; D010347:Patient Care Planning; D011874:Radiometry; D016634:Radiosurgery; D050397:Radiotherapy, Intensity-Modulated
keywords: Brain metastasis; CyberKnife; Dosimetric comparison; Radiosurgery; Tomotherapy