title: HDR brachytherapy irradiation of the jaw - as a new experimental model of radiogenic bone damage.
abstract: BACKGROUND
  Hitherto, no suitable experimental model exists to test new treatments for radiogenic bone damage, such as new step from knowledge about bone growth factors or angiogenesis factors. The goal of this investigation was to establish such a standardised experimental model.
  
  
  METHODS
  Twenty-four rats were used in this study. In 12 rats a plastic tube was implanted along the right half of the mandible and treated with a single dose of 20 Gy at a high-dose-rate (HDR) using an afterloading machine, the remainder served as control (n=12). One hundred days after irradiation both sides of the mandible were examined using paraffin embedding and non-decalcified histology.
  
  
  RESULTS
  All HDR irradiated rats developed localised alopecia within 2 weeks of radiotherapy. In the irradiated group, a clear growth reduction of the ipsilateral incisor was observed. Paraffin histology revealed minimal damage of the bone structure with slightly increased signs of regeneration. The bone apposition rate was significantly reduced on the irradiated right side, compared with the left side (p=0.028). The average diameter of the mandibular condyles on the irradiated right sides was significantly reduced when compared with the left sides (p=0.023).
  
  
  CONCLUSIONS
  It is possible to induce radiogenic damage of the mandible by using HDR brachytherapy with a single dose of 20 Gy comparable to 45 x 2 Gy of conventional irradiation. This new model is easy and predictable and appears to be suitable for the testing of new treatment modalities. It is advantageous for the testing of bone growth and angiogenesis factors that the contralateral side exhibits completely normal bone apposition characteristics enabling a split-mouth design for future experiments.
authors.affiliation: Department of Radiotherapy (Radiooncology), University of Kiel, Germany. niehoff@onco.uni-kiel.de
authors.forename: Peter
authors.initials: P
authors.lastname: Niehoff
authors.forename: Ingo N
authors.initials: IN
authors.lastname: Springer
authors.forename: Yahya
authors.initials: Y
authors.lastname: Açil
authors.forename: Andre
authors.initials: A
authors.lastname: Lange
authors.forename: Matthias
authors.initials: M
authors.lastname: Marget
authors.forename: J Camilo
authors.initials: JC
authors.lastname: Roldán
authors.forename: Klaas
authors.initials: K
authors.lastname: Köppe
authors.forename: Patrick H
authors.initials: PH
authors.lastname: Warnke
authors.forename: Bernhard
authors.initials: B
authors.lastname: Kimmig
authors.forename: Jörg
authors.initials: J
authors.lastname: Wiltfang
mesh_terms: D000505:Alopecia / Q000209:etiology; D000818:Animals; D001861:Bone Regeneration / Q000528:radiation effects*; D001918:Brachytherapy / Q000009:adverse effects*; D016371:Cranial Irradiation / Q000009:adverse effects*; D004307:Dose-Response Relationship, Radiation; D008297:Male; D008334:Mandible / Q000528:radiation effects*; D023421:Models, Animal; D010025:Osteoradionecrosis / Q000503:physiopathology; D011882:Radiotherapy, High-Energy / Q000009:adverse effects; D051381:Rats; D011916:Rats, Inbred F344; D011917:Rats, Inbred Lew; D011921:Rats, Inbred WKY; D018709:Statistics, Nonparametric; D014070:Tooth / Q000528:radiation effects