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Monte Carlo study of the potential reduction in out-of-field dose using a patient-specific aperture in pencil beam scanning proton therapy

Journal Article


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Abstract


  • This study is aimed at identifying the potential benefits of using a patientspecific

    aperture in proton beam scanning. For this purpose, an accurate Monte

    Carlo model of the pencil beam scanning (PBS) proton therapy (PT) treatment

    head at Massachusetts General Hospital (MGH) was developed based on

    an existing model of the passive double-scattering (DS) system. The Monte

    Carlo code specifies the treatment head at MGH with sub-millimeter accuracy.

    The code was configured based on the results of experimental measurements

    performed at MGH. This model was then used to compare out-of-field doses

    in simulated DS treatments and PBS treatments. For the conditions explored,

    the penumbra in PBS is wider than in DS, leading to higher absorbed doses

    and equivalent doses adjacent to the primary field edge. For lateral distances

    greater than 10 cm from the field edge, the doses in PBS appear to be lower

    than those observed for DS. We found that placing a patient-specific aperture

    at nozzle exit during PBS treatments can potentially reduce doses lateral to the

    primary radiation field by over an order of magnitude. In conclusion, using a

    patient-specific aperture has the potential to further improve the normal tissue

    sparing capabilities of PBS.

UOW Authors


  •   Dowdell, Stephen J. (external author)
  •   Clasie, Ben (external author)
  •   Depauw, Nicolas (external author)
  •   Metcalfe, Peter
  •   Rosenfeld, Anatoly B.
  •   Kooy, Hanne (external author)
  •   Flanz, J B (external author)
  •   Paganetti, Harald (external author)

Publication Date


  • 2012

Citation


  • Dowdell, S. J., Clasie, B., Depauw, N., Metcalfe, P. E., Rozenfeld, A., Kooy, H. M., Flanz, J. B. & Paganetti, H. (2012). Monte Carlo study of the potential reduction in out-of-field dose using a patient-specific aperture in pencil beam scanning proton therapy. Physics in Medicine and Biology, 57 (10), 2829-2842.

Scopus Eid


  • 2-s2.0-84860361249

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=7533&context=engpapers

Ro Metadata Url


  • http://ro.uow.edu.au/engpapers/4602

Number Of Pages


  • 13

Start Page


  • 2829

End Page


  • 2842

Volume


  • 57

Issue


  • 10

Abstract


  • This study is aimed at identifying the potential benefits of using a patientspecific

    aperture in proton beam scanning. For this purpose, an accurate Monte

    Carlo model of the pencil beam scanning (PBS) proton therapy (PT) treatment

    head at Massachusetts General Hospital (MGH) was developed based on

    an existing model of the passive double-scattering (DS) system. The Monte

    Carlo code specifies the treatment head at MGH with sub-millimeter accuracy.

    The code was configured based on the results of experimental measurements

    performed at MGH. This model was then used to compare out-of-field doses

    in simulated DS treatments and PBS treatments. For the conditions explored,

    the penumbra in PBS is wider than in DS, leading to higher absorbed doses

    and equivalent doses adjacent to the primary field edge. For lateral distances

    greater than 10 cm from the field edge, the doses in PBS appear to be lower

    than those observed for DS. We found that placing a patient-specific aperture

    at nozzle exit during PBS treatments can potentially reduce doses lateral to the

    primary radiation field by over an order of magnitude. In conclusion, using a

    patient-specific aperture has the potential to further improve the normal tissue

    sparing capabilities of PBS.

UOW Authors


  •   Dowdell, Stephen J. (external author)
  •   Clasie, Ben (external author)
  •   Depauw, Nicolas (external author)
  •   Metcalfe, Peter
  •   Rosenfeld, Anatoly B.
  •   Kooy, Hanne (external author)
  •   Flanz, J B (external author)
  •   Paganetti, Harald (external author)

Publication Date


  • 2012

Citation


  • Dowdell, S. J., Clasie, B., Depauw, N., Metcalfe, P. E., Rozenfeld, A., Kooy, H. M., Flanz, J. B. & Paganetti, H. (2012). Monte Carlo study of the potential reduction in out-of-field dose using a patient-specific aperture in pencil beam scanning proton therapy. Physics in Medicine and Biology, 57 (10), 2829-2842.

Scopus Eid


  • 2-s2.0-84860361249

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=7533&context=engpapers

Ro Metadata Url


  • http://ro.uow.edu.au/engpapers/4602

Number Of Pages


  • 13

Start Page


  • 2829

End Page


  • 2842

Volume


  • 57

Issue


  • 10