title: Comparison of EBT and EBT3 RadioChromic Film Usage in Parotid Cancer Radiotherapy.
abstract: BACKGROUND
  EBT and EBT3 radioChromic films have been used in radiotherapy dosimetry for years.
  
  
  OBJECTIVE
  The aim of the current study is to compare EBT and EBT3 radioChromic films in dosimetry of radiotherapy fields for treatment of parotid cancer.
  
  
  METHODS
  Calibrations of EBT and EBT3 films were performed with identical setups using a 6 MV photon beam of a Siemens Primus linac. Skin dose was measured at different points in the right anterior oblique (RAO) and right posterior oblique (RPO) fields by EBT and EBT3 films on a RANDO phantom.
  
  
  RESULTS
  While dosimetry was performed with the same conditions for the two film types for calibration and in phantom in parotid cancer radiotherapy, the measured net optical density (NOD) in EBT film was found to be higher than that from EBT3 film. The minimum difference between these two films under calibration conditions was about 2.9% (for 0.2 Gy) with a maximum difference of 35.5% (for 0.5 Gy). In the therapeutic fields of parotid cancer radiotherapy at different points, the measured dose from EBT film was higher than the EBT3 film. In these fields the minimum and maximum measured dose differences were 16.0% and 25.5%, respectively.
  
  
  CONCLUSIONS
  EBT film demonstrates higher NOD than EBT3 film. This effect may be related to the higher sensitivity of EBT film over EBT3 film. However, the obtained dose differences between these two films in low dose range can be due to the differences in fitting functions applied following the calibration process.
authors.affiliation: Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: M T
authors.initials: MT
authors.lastname: Bahreyni Toossi
authors.affiliation: Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: F
authors.initials: F
authors.lastname: Khorshidi
authors.affiliation: Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Ghorbani
authors.affiliation: Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: N
authors.initials: N
authors.lastname: Mohamadian
authors.affiliation: Comprehensive Cancer Centers of Nevada, Las Vegas, Nevada, USA.
authors.forename: D
authors.initials: D
authors.lastname: Davenport
keywords: EBT; EBT3; Parotid cancer; RadioChromic film; Radiotherapy