title: Biodosimetric quantification of short-term synchrotron microbeam versus broad-beam radiation damage to mouse skin using a dermatopathological scoring system.
abstract: OBJECTIVE
  Microbeam radiotherapy (MRT) with wafers of microscopically narrow, synchrotron generated X-rays is being used for pre-clinical cancer trials in animal models. It has been shown that high dose MRT can be effective at destroying tumours in animal models, while causing unexpectedly little damage to normal tissue. The aim of this study was to use a dermatopathological scoring system to quantify and compare the acute biological response of normal mouse skin with microplanar and broad-beam (BB) radiation as a basis for biological dosimetry.
  
  
  METHODS
  The skin flaps of three groups of mice were irradiated with high entrance doses (200 Gy, 400 Gy and 800 Gy) of MRT and BB and low dose BB (11 Gy, 22 Gy and 44 Gy). The mice were culled at different time-points post-irradiation. Skin sections were evaluated histologically using the following parameters: epidermal cell death, nuclear enlargement, spongiosis, hair follicle damage and dermal inflammation. The fields of irradiation were identified by γH2AX-positive immunostaining.
  
  
  RESULTS
  The acute radiation damage in skin from high dose MRT was significantly lower than from high dose BB and, importantly, similar to low dose BB.
  
  
  CONCLUSIONS
  The integrated MRT dose was more relevant than the peak or valley dose when comparing with BB fields. In MRT-treated skin, the apoptotic cells of epidermis and hair follicles were not confined to the microbeam paths.
authors.affiliation: Department of Pathology, Southern Health, Monash Medical Centre, Clayton, Victoria, Australia.
authors.forename: R C U
authors.initials: RC
authors.lastname: Priyadarshika
authors.forename: J C
authors.initials: JC
authors.lastname: Crosbie
authors.forename: B
authors.initials: B
authors.lastname: Kumar
authors.forename: P A W
authors.initials: PA
authors.lastname: Rogers
mesh_terms: D000818:Animals; D004307:Dose-Response Relationship, Radiation; D005260:Female; D007150:Immunohistochemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D011829:Radiation Dosage; D011833:Radiation Injuries, Experimental / Q000473:pathology*; D011874:Radiometry / Q000379:methods*; D012867:Skin / Q000473:pathology* / Q000528:radiation effects*; D017356:Synchrotrons