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Evaluation of Two Radiochromic Films for HVL Measurement

  • T. Gotanda
  • T. Katsuda
  • R. Gotanda
  • A. Tabuchi
  • K. Yamamoto
  • T. Kuwano
  • H. Yatake
  • K. Kashiyama
  • K. Yabunaka
  • T. Akagawa
  • Y. Takeda
Conference paper
Part of the IFMBE Proceedings book series (IFMBE, volume 37)

Abstract

Although the half-value layer (HVL) is one of the important parameters for quality assurance (QA) and quality control (QC), constant monitoring has not been performed because measurements using an ionization chamber (IC) are time-consuming. To solve these problems, a method using radiochromic film and step-shaped aluminum (Al) filters has been developed. In this study, GAFCHROMIC EBT2 dosimetry film (GAF-EBT2) and GAFCHROMIC XR TYPE-R dosimetry film (GAF-R) has been used. The measurement X-ray tube voltage was 120 kV. Two radiochromic films were scanned using a flat-bed scanner. To remove the nonuniformity error of scanned images, image J version 1.40g image analysis software has been used. HVL was evaluated using the density attenuation ratio. The HVLs and second HVLs of GAF-EBT2, GAF-R, and an IC dosimeter were compared. The HVLs (second HVLs) at 120 kV using GAF-EBT2, GAF-R, and an IC dosimeter were 4.47 mm (10.97 mm), 4.17 mm (8.61 mm), and 4.03 mm (10.35 mm) respectively, and the effective energies were 40.6 keV, 39.3 keV, and 38.7 keV, respectively. The difference ratios of the second HVLs using GAF-EBT2 (GAF-R) and an IC dosimeter were 6.0% (– 16.8%), –10.6% (–11.6%), and 5.1% (–0.2%), respectively. In addition, the difference ratio of the second HVLs at 120 kV using GAF-EBT2 and GAF-R was 27.4%. GAF-EBT2 and GAF-R proved to be capable of measuring effective energy within an error range of less than 5%. However, in HVL measurements of devices operating in the high-energy range (X-ray CT, radiotherapy machines, and so on), GAF-EBT2 was found to offer higher measurement precision than GAF-R, because it shows only a slight energy dependency.

Keywords

radiochromic film effective energy half-value layer quality assurance quality control 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  • T. Gotanda
    • 1
    • 2
  • T. Katsuda
    • 3
  • R. Gotanda
    • 4
    • 5
  • A. Tabuchi
    • 6
  • K. Yamamoto
    • 7
  • T. Kuwano
    • 5
  • H. Yatake
    • 5
  • K. Kashiyama
    • 5
  • K. Yabunaka
    • 8
  • T. Akagawa
    • 9
  • Y. Takeda
    • 5
  1. 1.Department of RadiologyOishi HospitalHiroshimaJapan
  2. 2.Faculty of Health Care SciencesHimeji Dokkyo UniversityHimejiJapan
  3. 3.Faculty of Radiologic TecnologySeikeikai CollegeOsakaJapan
  4. 4.School of Health SciencesIbaraki Prefectural University of Health SciencesIbarakiJapan
  5. 5.Graduate School of Health SciencesOkayama UniversityOkayamaJapan
  6. 6.Kawasaki Medical School Kawasaki HospitalOkayamaJapan
  7. 7.Department of RadiologyOsaka Cancer Prevention and Detection CenterOsakaJapan
  8. 8.Department of RadiologyKatsuragi HospitalOsakaJapan
  9. 9.Department of Radiological TechnologyTokushima Red Cross HospitalTokushimaJapan

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