title: High-resolution fiber-optic dosimeters for microbeam radiation therapy.
abstract: OBJECTIVE
  A high resolution, water equivalent, optical and passive x-ray dosimeter has been constructed using plastic scintillator and optical fiber. This dosimeter has a peak edge-on spatial resolution of 100 μm in one dimension, with a 10 μm resolution dosimeter under investigation. The dosimeter design has a potential application in synchrotron x-ray microbeam radiation therapy where a high resolution is vital for accurate dose measurements and quality assurance.
  
  
  METHODS
  BC-400 plastic scintillator, of thickness 100 μm, was optically coupled to an optical fiber with core diameter 1 mm. The end was coated in optical paint to improve sensitivity. An identical fiber was made without the scintillator to measure the background Cherenkov radiation induced in the fiber, to allow background signal subtraction. The light captured by the fibers was measured by PMTs. The probe system was exposed to a 6 MV, 10 × 10 cm2LINAC x-ray field and the beam profile was measured at 100 cm, as well as the depth dose profile.
  
  
  RESULTS
  The measured profiles matched well with ionisation chamber data. Important beam parameters such as penumbra width and percent depth dose at various depths matched the ionisation chamber data, within uncertainty.
  
  
  CONCLUSIONS
  This work demonstrates that high resolutions can be achieved with a scintillation and optical fiber system. The probe is water-equivalent, passive, energy independent, radiation hard and inexpensive, making it ideal for further improvements for use with microbeam radiation therapy.
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.
authors.forename: James
authors.initials: J
authors.lastname: Archer
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.
authors.forename: Enbang
authors.initials: E
authors.lastname: Li
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.
authors.forename: Marco
authors.initials: M
authors.lastname: Petasecca
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Lerch
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.
authors.forename: Anatoly
authors.initials: A
authors.lastname: Rosenfeld
authors.affiliation: Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, NSW, 2500, Australia.
authors.forename: Martin
authors.initials: M
authors.lastname: Carolan
mesh_terms: D005336:Fiber Optic Technology; D055100:Optical Fibers; D000072232:Radiation Dosimeters; D011874:Radiometry; D012588:Scintillation Counting; D014965:X-Rays
keywords: fiber-optic dosimetry; microbeam radiation therapy; scintillators; x-ray