title: Feasibility of using glass-bead thermoluminescent dosimeters for radiotherapy treatment plan verification.
abstract: OBJECTIVE
  To investigate the feasibility of using glass beads as novel thermoluminescent dosemeters (TLDs) for radiotherapy treatment plan verification.
  
  
  METHODS
  Commercially available glass beads with a size of 1-mm thickness and 2-mm diameter were characterized as TLDs. Five clinical treatment plans including a conventional larynx, a conformal prostate, an intensity-modulated radiotherapy (IMRT) prostate and two stereotactic body radiation therapy (SBRT) lung plans were transferred onto a CT scan of a water-equivalent phantom (Solid Water(®), Gammex, Middleton, WI) and the dose distribution recalculated. The number of monitor units was maintained from the clinical plan and delivered accordingly. The doses determined by the glass beads were compared with those measured by a graphite-walled ionization chamber, and the respective expected doses were determined by the treatment-planning system (TPS) calculation.
  
  
  RESULTS
  The mean percentage difference between measured dose with the glass beads and TPS was found to be 0.3%, -0.1%, 0.4%, 1.8% and 1.7% for the conventional larynx, conformal prostate, IMRT prostate and each of the SBRT delivery techniques, respectively. The percentage difference between measured dose with the ionization chamber and glass bead was found to be -1.2%, -1.4%, -0.1%, -0.9% and 2.4% for the above-mentioned plans, respectively. The results of measured doses with the glass beads and ionization chamber in comparison with expected doses from the TPS were analysed using a two-sided paired t-test, and there was no significant difference at p < 0.05.
  
  
  CONCLUSIONS
  It is feasible to use glass-bead TLDs as dosemeters in a range of clinical plan verifications.
  
  
  CONCLUSIONS
  Commercial glass beads are utilized as low-cost novel TLDs for treatment-plan verification.
authors.affiliation: 1 Department of Physics, University of Surrey, London, UK.|2 Radiology Department, Faculty of Medicine, Kabul Medical University, Kabul, Afghanistan.
authors.forename: Shakardokht M
authors.initials: SM
authors.lastname: Jafari
authors.affiliation: 3 Department of Medical Physics, Royal Surrey County Hospital NHS Trust, London, UK.
authors.forename: Tom J
authors.initials: TJ
authors.lastname: Jordan
authors.affiliation: 3 Department of Medical Physics, Royal Surrey County Hospital NHS Trust, London, UK.
authors.forename: Gail
authors.initials: G
authors.lastname: Distefano
authors.affiliation: 1 Department of Physics, University of Surrey, London, UK.|4 Department of Physics, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: David A
authors.initials: DA
authors.lastname: Bradley
authors.affiliation: 1 Department of Physics, University of Surrey, London, UK.
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Spyrou
authors.affiliation: 1 Department of Physics, University of Surrey, London, UK.|3 Department of Medical Physics, Royal Surrey County Hospital NHS Trust, London, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Nisbet
authors.affiliation: 1 Department of Physics, University of Surrey, London, UK.|3 Department of Medical Physics, Royal Surrey County Hospital NHS Trust, London, UK.|5 Radiation Dosimetry Group, National Physical Laboratory, London, UK.
authors.forename: Catharine H
authors.initials: CH
authors.lastname: Clark
mesh_terms: D002138:Calibration; D005240:Feasibility Studies; D005898:Glass; D006801:Humans; D019047:Phantoms, Imaging; D016634:Radiosurgery; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal; D050397:Radiotherapy, Intensity-Modulated; D013819:Thermoluminescent Dosimetry / Q000295:instrumentation*