title: A unique alpha dosimetry technique using Gafchromic EBT3(®) film and feasibility study for an activity calibrator for alpha-emitting radiopharmaceuticals.
abstract: OBJECTIVE
  To develop an alpha dosimetry technique for activity calibration of alpha-emitting radiopharmaceuticals using the Gafchromic(®) EBT3 (Gaf-EBT3) radiochromic film (International Speciality product, Wayne, NJ).
  
  
  METHODS
  The Gaf-EBT3 has a tissue equivalent radiosensitive layer (approximately 28 μm) sandwiched between two 100-μm thick polyester sheaths, thereby making it insensitive to alpha particles. We have split a Gaf-EBT3 sheet using a surgical scalpel to remove one of the polyester protective layers and covered the radiosensitive layer with thin Mylar(®) foil (Goodfellow Cambridge Limited, Huntingdon, UK) (2.5 μm). Small pieces of modified film were exposed at contact with a 560-Bq thin (241)Am source for 5, 10, 24 and 94 h. The optical density of the films was evaluated using an optical densitometer. The alpha energy spectra of the (241)Am source were recorded using a Si(Li) surface barrier detector.
  
  
  RESULTS
  Time-integrated specific alpha surface activity (kBq cm(-2) h) was represented as a function of optical density.
  
  
  CONCLUSIONS
  By removing one of the 100 μm thick polyester protective layers, the authors have modified the Gaf-EBT3 film to a sensitive alpha dosemeter. The calibration function relevant to a (241)Am reference source was evaluated from the optical densities of the dosemeter foils. Furthermore, calibration functions for important alpha emitters such as (223)Ra, (225)Ac or (210)Bi were parameterized from the (241)Am reference data.
  
  
  CONCLUSIONS
  The authors have developed and tested the principle of a clinical alpha dosemeter using Gaf-EBT3 radiochromic films originally developed for photon dosimetry. This novel, user-friendly technique could be implemented in quality assurance and calibration procedures of important alpha-emitting radiopharmaceuticals prior to their clinical applications.
authors.affiliation: 1 Detector and Sensor Group, West German Proton Therapy Centre Essen (WPE), Essen, Germany.|2 Department of Medical Physics, School of Physics (A28), The University of Sydney, Sydney, NSW, Australia.
authors.forename: Bhaskar
authors.initials: B
authors.lastname: Mukherjee
authors.affiliation: 2 Department of Medical Physics, School of Physics (A28), The University of Sydney, Sydney, NSW, Australia.
authors.forename: Yaser H
authors.initials: YH
authors.lastname: Gholami
authors.affiliation: 3 Division of Physical and Chemical Sciences, International Atomic Energy Agency (IAEA), Vienna, Austria.
authors.forename: Uday
authors.initials: U
authors.lastname: Bhonsle
authors.affiliation: 1 Detector and Sensor Group, West German Proton Therapy Centre Essen (WPE), Essen, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Hentschel
authors.affiliation: 2 Department of Medical Physics, School of Physics (A28), The University of Sydney, Sydney, NSW, Australia.
authors.forename: Joseph
authors.initials: J
authors.lastname: Khachan
mesh_terms: D002138:Calibration; D005240:Feasibility Studies; D005373:Film Dosimetry / Q000295:instrumentation*; D006801:Humans; D019047:Phantoms, Imaging; D011874:Radiometry / Q000379:methods*; D019275:Radiopharmaceuticals; D011879:Radiotherapy Dosage
chemical_list: D019275:Radiopharmaceuticals