title: Collimator design for experimental minibeam radiation therapy.
abstract: OBJECTIVE
  To design and optimize a minibeam collimator for minibeam radiation therapy studies using a 250 kVp x-ray machine as a simulated synchrotron source.
  
  
  METHODS
  A Philips RT250 orthovoltage x-ray machine was modeled using the EGSnrc/BEAMnrc Monte Carlo software. The resulting machine model was coupled to a model of a minibeam collimator with a beam aperture of 1 mm. Interaperture spacing and collimator thickness were varied to produce a minibeam with the desired peak-to-valley ratio.
  
  
  RESULTS
  Proper design of a minibeam collimator with Monte Carlo methods requires detailed knowledge of the x-ray source setup. For a cathode-ray tube source, the beam spot size, target angle, and source shielding all determine the final valley-to-peak dose ratio.
  
  
  CONCLUSIONS
  A minibeam collimator setup was created, which can deliver a 30 Gy peak dose minibeam radiation therapy treatment at depths less than 1 cm with a valley-to-peak dose ratio on the order of 23%.
authors.affiliation: Saskatoon Cancer Centre, 20 Campus Drive, Saskatoon, Saskatchewan S7N 4H4, Canada. kerbab@sasktel.net
authors.forename: Kerry
authors.initials: K
authors.lastname: Babcock
authors.forename: Narinder
authors.initials: N
authors.lastname: Sidhu
authors.forename: Vijayananda
authors.initials: V
authors.lastname: Kundapur
authors.forename: Kaiser
authors.initials: K
authors.lastname: Ali
mesh_terms: D000818:Animals; D004867:Equipment Design; D051379:Mice; D009010:Monte Carlo Method; D011878:Radiotherapy / Q000295:instrumentation*; D011879:Radiotherapy Dosage