Evaluation of film dosimetry for narrow photon beams using linear accelerator

• Gotoh Shinichi

  Division of Radiological Technology, Nagasaki University Hospital

Bibliographic Information

Other Title

• 写真フィルムによるナロー一ビームの線量評価

Abstract

Narrow photon beam dosimetry used in stereotactic radiosurgery can be made difficult because of the presence of lateral electoronic disequilibrium and steep dose gradiants. Dosimetric characteristics of 10MV circular narrow photon beams ranging in size from 11.6 to 31.4 mm are reported. These characteristics include the measurement of tissue maximum ratio, off axis ratio and relative output factors. Measurements of these parameters were performed in a solid water phantom using x-ray films and cylindrical micro ionization chamber. Although in 50% isodose level width the measurement by micro ionization chamber and x-ray film correlated well, in 80% isodose level width measurement by micro chamber showed apparent underevaluation than that by x-ray film. The relative output factors measurement by micro ionization chamber was consistent with that by x-ray film within 3 % for the field size between 11.6 and 31.4 mm φ.

Journal

• Japanese Journal of Medical Physics

  Japanese Journal of Medical Physics 17 (1), 9-14, 1997

  Japan Society of Medical Physics

Keywords

• narrow photon beam
• stereotactic radiosurgery
• linear accelerator
• x-ray film
• dosimetry

Details

• CRID: 1390001204672163968
• NII Article ID: 10003723851
• NII Book ID: AA11137895
• DOI: 10.11323/jjmp1992.17.1_9
• ISSN: 21869855
• ISSN: 09188010
• Text Lang: ja
• Data Source:
  • JaLC
  • CiNii Articles
• Abstract License Flag: Disallowed