Superficial dose distribution in breast for tangential radiation treatment of breast cancer

ORAL

Abstract

The superficial (0-2 cm) dose distribution in a cylindrical phantom is examined theoretically and experimentally when irradiated by tangential photon beams. The lateral superficial part of the phantom is shown to receive full dose beyond 2 mm whereas the build-up region is up to 7 mm where the beams enter. Eclipse AAA calculations agree well with the experimental and Monte Carlo data while Eclipse PBC underestimates the entrance dose the first 3-4 mm and fails to give a correct lateral dose close to the surface up to 10 mm depth. The performance of the Eclipse algorithms is evaluated in a number of clinical cases with Monte Carlo results. Examples are given to illustrate how differences in geometrical presentation of the body structure in the treatment planning system and the Monte Carlo simulation as well as the patient voxelization may affect the evaluation results.

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Authors

  • Roumiana Chakarova

    Sahlgrenska University Hospital, Dept. of Medical Physics and Biomedical Engineering, Gothenburg, 413 45 Sweden

  • Magnus Gustafsson

    Sahlgrenska University Hospital, Dept. of Medical Physics and Biomedical Engineering, Gothenburg, 413 45 Sweden

  • Anna Baeck

    Sahlgrenska University Hospital, Dept. of Medical Physics and Biomedical Engineering, Gothenburg, 413 45 Sweden

  • Ninni Drugge

    Sahlgrenska University Hospital, Dept. of Medical Physics and Biomedical Engineering, Gothenburg, 413 45 Sweden

  • Asa Palm

    Sahlgrenska University Hospital, Dept. of Medical Physics and Biomedical Engineering, Gothenburg, 413 45 Sweden

  • Andreas Lindberg

    Sahlgrenska University Hospital, Dept. of Medical Physics and Biomedical Engineering, Gothenburg, 413 45 Sweden

  • Mattias Berglund

    Sahlgrenska University Hospital, Dept. of Medical Physics and Biomedical Engineering, Gothenburg, 413 45 Sweden