title: DVHs evaluation in brain metastases stereotactic radiotherapy treatment plans.
abstract: OBJECTIVE
  The aim of this work is to report a retrospective study of radiobiological indicators based on Dose-Volume Histograms analysis obtained by stereotactic radiotherapy treatments.
  
  
  METHODS
  Fifty-five patients for a total of sixty-seven brain metastases with a mean target volume of 8.49 cc were treated by Dynamic Conformal Arc Therapy (DCAT) and Intensity-Modulated Stereotactic Radiotherapy (IMRST). The Delivered prescription dose was chosen on the basis of tumor size and location so as to ensure a 100% isodose coverage to the target volume.
  
  
  RESULTS
  The treatment plans reported a mean value of 10% and 2.19% for the inhomogeneity and conformal index, respectively. The F factor showed we overdosed sixty-three patients delivering an additional 7% dose more than calculated values. The radiobiological parameters: TCP and NTCP showed a complete tumor control limiting the organs at risk damage.
  
  
  CONCLUSIONS
  One goal of stereotactic radiotherapy is to design a treatment plan in which the steep dose gradient achievable minimizes the amount of radiation delivered outside the tumor region. This technique allows to deliver a much larger dose to the target without exceeding the radiation-related tolerance of normal tissues and improving patients' quality of life.
authors.affiliation: Laboratory of Medical Physics and Expert Systems, Regina Elena National Cancer Institute, Rome, Italy. ka.pasciuti@libero.it
authors.forename: Katia
authors.initials: K
authors.lastname: Pasciuti
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Iaccarino
authors.forename: Antonella
authors.initials: A
authors.lastname: Soriani
authors.forename: Vicente
authors.initials: V
authors.lastname: Bruzzaniti
authors.forename: Simona
authors.initials: S
authors.lastname: Marzi
authors.forename: Sara
authors.initials: S
authors.lastname: Gomellini
authors.forename: Stefano
authors.initials: S
authors.lastname: Arcangeli
authors.forename: Marcello
authors.initials: M
authors.lastname: Benassi
authors.forename: Valeria
authors.initials: V
authors.lastname: Landoni
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000532:radiotherapy* / Q000556:secondary; D005260:Female; D006801:Humans; D007103:Immobilization; D008297:Male; D008875:Middle Aged; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies; D013238:Stereotaxic Techniques; D016896:Treatment Outcome