Determination of overall perturbation factors forplane-parallel ionization chambers in electron beams

• Araki Fujio

  Department of Radiological Technology, Kumamoto University College of Medical Science

• Shirakawa Yuichi

  Department of Radiology, Kumamoto University Hospital

• Ikeda Ryuji

  Department of Radiology, Kumamoto University Hospital

• Shimonobou Toshiaki

  Department of Radiology, Kumamoto University Hospital

• Moribe Nobuyuki

  Department of Radiology, Kumamoto University Hospital

• Takada Takao

  Department of Radiology, Kumamoto University Hospital

• Takahashi Mutsumasa

  Department of Radiology, Kumamoto University Hospital

• Oura Hiroki

  Department of Radiology, Kumamoto National Hospital

• Matoba Masaru

  Department of Applied Quantum Physics and Nuclear Engineering, Graduate School of Engineering, Kyushu University

抄録

Most dosimetry protocols recommend the use of plane-parallel chambers for dose determination in electron beams with energies below 10 MeV. The new IAEA TRS 381 (1997) protocol includes the overall perturbation factor P_Q that consists of the inscattering correction factor P_cav(ar P_repi) and the wall correction factor P_wall(or P_wall)I. n this work, P_Qc for the commonly applied NACP, PTW/Roos and PTW/Markus planeparallel chambers was determined experimentally. For the NACP plane-parallel chamber, P_Q was obtained by comparison with a cylindrical Farmer chamber, while for the PTW/Roos and PTW/Markus chambers it was obtained by comparison with the NACP chamber. The values of P_Q for these plane-parallel chambers were measured as a function of mean electron energies ,E_z from 1.7 MeV to 11.5 MeV. It was found that for the NACP and PTW/Roos chambers, P_Q is independent of energy down to E_z= 1.7MeV, while for the PTW/Markus chamber it shows a systematic and exponential drop of about 2% with decreasing energy down to E_z=2.7 MeV. However, the decrease of P_Q for E_z=1.7 MeV was not exponential.

収録刊行物

• Japanese Journal of Medical Physics

  Japanese Journal of Medical Physics 20 (2), 95-103, 2000

  Japan Society of Medical Physics

キーワード

• plane-parallel ionization chamber
• overall perturbation factor
• electron dosimetry

詳細情報

• CRID: 1390282679648480512
• NII論文ID: 10004573876
• NII書誌ID: AA11580542
• DOI: 10.11323/jjmp2000.20.2_95
• NDL書誌ID: 5673741
• ISSN: 13455354
• PubMed: 12764248
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I5673741
• 本文言語コード: en
• データソース種別:
  • JaLC
  • NDL
  • PubMed
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可