title: In vivo dosimetry in the field junction area for 3D-conformal radiation therapy in breast and head & neck cancer cases: A quality assurance study.
abstract: OBJECTIVE
  To investigate the accuracy of field junctioning planning techniques (monoisocentric and rotating couch technique) for 3D-conformal radiotherapy (3D-CRT).
  
  
  METHODS
  In vivo dosimetry has been performed using thermo- luminescence dosimeters (TLDs) in 10 head and neck cancer patients (treated with monoisocentric technique) and 10 breast cancer patients (treated with rotating couch technique) irradiated with a 6 MV photon beam. Entrance dose measurements were performed in selected regions including the field junction area.
  
  
  RESULTS
  The mean deviation between measured and expected dose in the region of junction was significantly higher in breast cases compared to head and neck irradiation (-2.8±15.4% and 0.2±8.2% respectively; Mann-Whitney U test: p=0.002). A comparison between lateral head and neck fields and tangential breast fields revealed that the latter was associated with larger dose discrepancies (-2.2 ± 4.6% vs -3.5 ± 5.7% respectively; Mann-Whitney U test: p=0.029).
  
  
  CONCLUSIONS
  The results indicate the superiority of monoisocentric technique compared to the rotating couch technique in terms of dose delivery accuracy for treatments with field junctioning planning techniques.
authors.affiliation: Second Department of Radiology, Medical School, University of Athens, University General Hospital "Attikon", Athens, Greece.
authors.forename: Stefanos
authors.initials: S
authors.lastname: Diamantopoulos
authors.forename: Stella
authors.initials: S
authors.lastname: Thalassinou
authors.forename: Efstathios
authors.initials: E
authors.lastname: Efstathopoulos
authors.forename: Maria
authors.initials: M
authors.lastname: Dilvoi
authors.forename: Georgios
authors.initials: G
authors.lastname: Patatoukas
authors.forename: Vassilis
authors.initials: V
authors.lastname: Kouloulias
authors.forename: Kalliopi
authors.initials: K
authors.lastname: Platoni
mesh_terms: D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D006258:Head and Neck Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D011785:Quality Assurance, Health Care / Q000592:standards; D011829:Radiation Dosage; D000069079:Radiation Exposure / Q000592:standards; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods* / Q000592:standards; D020266:Radiotherapy, Conformal / Q000592:standards; D015203:Reproducibility of Results; D013819:Thermoluminescent Dosimetry / Q000592:standards