title: Case control study to assess the possibility of decrease the risk of osteoradionecrosis in relation to the dose of radiation absorbed by the jaw.
abstract: OBJECTIVE
  the assessment of the limit dose for the organs at risk in external radiotherapy is a fundamental step to guarantee an optimal risk-benefit ratio. The aim of this study was to assess, through contouring the single dental cavities, the absorbed radiation dose on irradiated alveolar bones during the treatment of cervico-facial tumours, so as to test the correlation between the absorbed dose of radiation at alveolar level and the level of individual surgical risk for osteonecrosis.
  
  
  METHODS
  we selected 45 out of 89 patients on the basis of different exclusion criteria. Nine of these patients showed evidence of osteoradionecrosis. The patients were treated either with 3D conformational radiation therapy (3D-CRT) or with intensity-modulated radiation therapy (IMRT), there after alveolar bones were contoured using computed axial tomography (CAT scans) carried out following oncological and dental treatment. The dose-volume histograms (DVH) were obtained on the basis of such data, which included those relating to the dental cavities in addition to those inherent to the tumours and the organs at risk.
  
  
  RESULTS
  all patients, irrespective of type of treatment, received an average of 60 to 70 grays in 30/35 sittings. The patients treated with IMRT showed higher variation in absorbed radiation dose than those treated with 3D-CRT. The alveolar encirclement allowed the assessment of the absorbed radiation dose, and consequently it also allowed to assess the individual surgical risk for osteonecrosis in patients with head and neck tumours who underwent radiography treatment.
  
  
  CONCLUSIONS
  the study of DVH allows the assessment of limit dose and the detection of the areas at greater risk for osteoradionecrosis before dental surgery.
authors.affiliation: Research Professor, University of Milan-Bicocca, Monza (MB), Italy;
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Carini
authors.forename: Concetta
authors.initials: C
authors.lastname: Bucalo
authors.forename: Vito
authors.initials: V
authors.lastname: Saggese
authors.forename: Dario
authors.initials: D
authors.lastname: Monai
authors.forename: Gianluca
authors.initials: G
authors.lastname: Porcaro
keywords: IMRT; contouring; osteoradionecrosis