title: High sensitivity radiochromic film dose comparisons.
abstract: This short note investigates the dose characteristics of a relatively new high sensitivity radiochromic film (Gafchromic HS) and compares dose and energy response to various Gafchromic film types and radiographic (EDR-2) film. The original MD-55-1 and two improved sensitivity films, MD-55-2 and HS film, were investigated for energy and dose response. Results show that the energy response of the new HS film is relatively the same as the original MD-55-1 and MD-55-2 films with a decrease in sensitivity at lower x-ray energies, with response decreasing down to approximately 0.64 (normalized to 1 for a 6 MV beam) for a 28 keV effective energy beam. This is compared to an over response of 9.2 at the same energy for EDR-2 film. The dose response at the maximum absorption peak was found to be approximately 3.8 and 1.9 times more sensitive than MD-55-1 and MD-55-2 films, respectively. At the absorption peak yielding the maximum optical density change, HS was found to be approximately 0.2 to 0.25 times the sensitivity of EDR-2.
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong, Kowloon Tong, Hong Kong. butsonm@iahs.nsw.gov.au
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Butson
authors.forename: Peter K N
authors.initials: PK
authors.lastname: Yu
authors.forename: Tsang
authors.initials: T
authors.lastname: Cheung
authors.forename: Peter
authors.initials: P
authors.lastname: Metcalfe
mesh_terms: D004307:Dose-Response Relationship, Radiation; D019544:Equipment Failure Analysis / Q000379:methods*; D005373:Film Dosimetry / Q000295:instrumentation* / Q000379:methods; D008422:Materials Testing / Q000379:methods*; D011786:Quality Control; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation*; D020266:Radiotherapy, Conformal / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity