Evaluation of effective energy using radiochromic film and a step-shaped aluminum filter

T. Gotanda, T. Katsuda, R. Gotanda, A. Tabuchi, K. Yamamoto, T. Kuwano, H. Yatake, K. Kashiyama, K. Yabunaka, T. Akagawa, Y. Takeda

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)


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 and complicated. To solve these problems, a method using radiochromic film and step-shaped aluminum (Al) filters has been developed. To this end, GAFCHROMIC EBT2 dosimetry film (GAF-EBT2), which shows only slight energy dependency errors in comparison with GAFCHROMIC XR TYPE-R (GAF-R) and other radiochromic films, has been used. The measurement X-ray tube voltages were 120, 100, and 80 kV. GAF-EBT2 was scanned using a flat-bed scanner before and after exposure. To remove the non-uniformity error caused by image acquisition of the flat-bed scanner, the scanning image of the GAF-EBT2 before exposure was subtracted after exposure. HVL was evaluated using the density attenuation ratio. The effective energies obtained using HVLs of GAF-EBT2, GAF-R, and an IC dosimeter were compared. Effective energies with X-ray tube voltages of 120, 100, and 80 kV using GAF-EBT2 were 40.6, 36.0, and 32.9 keV, respectively. The difference ratios of the effective energies using GAF-EBT2 and the IC were 5.0%, 0.9%, and 2.7%, respectively. GAF-EBT2 and GAF-R proved to be capable of measuring effective energy with comparable precision. 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.

Original languageEnglish
Pages (from-to)213-222
Number of pages10
JournalAustralasian Physical and Engineering Sciences in Medicine
Issue number2
Publication statusPublished - Jun 1 2011


  • Effective energy
  • Half-value layer
  • Quality assurance
  • Quality control
  • Radiochromic film

ASJC Scopus subject areas

  • Biophysics
  • Biomedical Engineering
  • Radiology Nuclear Medicine and imaging
  • Physics and Astronomy(all)


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