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Couch modelling for volumetric modulated arc therapy (VMAT)

Australasian Physical & Engineering Sciences in Medicine volume 40, pages 471–480 (2017)Cite this article

Abstract

The aim of this work was to investigate the impact of the accuracy of a certain couch model on the overall accuracy of the dose calculation. For this purpose two models of the Varian Exact Couch (Varian Medical Systems, Palo Alto, CA, USA) for use in the planning of volumetric modulated arc therapy (VMAT) were created in Monaco 5.1 (Elekta, Stockholm, Sweden). The first was a simplistic model, with the relative electron densities (ED) of structures based entirely on CT Hounsfield units (HU). The second couch model was obtained by assigning the appropriate EDs to the relevant couch structures. Instead of getting EDs from the CT scan using the Hounsfield units to ED conversion, the second approach was to determine the optimal ED iteratively. The values accepted for the second couch model were the EDs that produced the best agreement between Monaco calculations and the measured couch attenuation. Finally, the performance of the two couch models in clinical prostate VMAT plans was compared.

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Affiliations

  1. Oncology and Haematology Service, Southern District Health Board, Dunedin Hospital 201 Great King Street, Dunedin, New Zealand

    Te-yu Chyou & Friedlieb Lorenz

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  1. Te-yu Chyou
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  2. Friedlieb Lorenz
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Correspondence to Te-yu Chyou.

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Chyou, Ty., Lorenz, F. Couch modelling for volumetric modulated arc therapy (VMAT). Australas Phys Eng Sci Med 40, 471–480 (2017). https://doi.org/10.1007/s13246-017-0552-4

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  • DOI: https://doi.org/10.1007/s13246-017-0552-4

Keywords

  • Couch model
  • Couch attenuation
  • Carbon fiber
  • Couch top