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Dosimetric verification of helical tomotherapy for total scalp irradiation

Journal Article


Abstract


  • Total scalp irradiation is a treatment technique used for a variety of supercial malignancies.

    Helical tomotherapy is an effective technique used for total scalp irradiation. Recent published

    work has shown the TomoTherapy planning system to overestimate the supercial dose. In this

    study, the supercial doses for a helical tomotherapy total scalp irradiation have been measured on

    an anthropomorphic phantom using radiochromic and radiographic lm as well as a new skin

    dosimeter, the MOSkin. The supercial dose was found to be accurately calculated by the Tomo-

    Therapy planning system. This is in contrast to recent reports, probably due to a combination of the

    smaller dose grid resolution used in planning and this particular treatment primarily consisting of

    beamlets tangential to the scalp. The supercial dose was found to increase from 33.6 to 41.2 Gy

    and 36.0 to 42.0 Gy over the rst 2 mm depth in the phantom in selected regions of the PTV,

    measured with radiochromic lm. The prescription dose was 40 Gy. The supercial dose was at the

    prescription dose or higher in some regions due to the bolus effect of the thermoplastic head mask

    and the head rest used to aid treatment setup. It is suggested that to achieve the prescription dose at

    the surface 2 mm depth bolus or a custom thermoplastic helmet is used

Publication Date


  • 2008

Citation


  • Hardcastle, N., Soisson, E., Metcalfe, P. E., Rozenfeld, A. & Tomé, W. (2008). Dosimetric verification of helical tomotherapy for total scalp irradiation. Medical Physics, 35 (11), 5061-5068.

Scopus Eid


  • 2-s2.0-54949142565

Ro Metadata Url


  • http://ro.uow.edu.au/engpapers/1798

Number Of Pages


  • 7

Start Page


  • 5061

End Page


  • 5068

Volume


  • 35

Issue


  • 11

Abstract


  • Total scalp irradiation is a treatment technique used for a variety of supercial malignancies.

    Helical tomotherapy is an effective technique used for total scalp irradiation. Recent published

    work has shown the TomoTherapy planning system to overestimate the supercial dose. In this

    study, the supercial doses for a helical tomotherapy total scalp irradiation have been measured on

    an anthropomorphic phantom using radiochromic and radiographic lm as well as a new skin

    dosimeter, the MOSkin. The supercial dose was found to be accurately calculated by the Tomo-

    Therapy planning system. This is in contrast to recent reports, probably due to a combination of the

    smaller dose grid resolution used in planning and this particular treatment primarily consisting of

    beamlets tangential to the scalp. The supercial dose was found to increase from 33.6 to 41.2 Gy

    and 36.0 to 42.0 Gy over the rst 2 mm depth in the phantom in selected regions of the PTV,

    measured with radiochromic lm. The prescription dose was 40 Gy. The supercial dose was at the

    prescription dose or higher in some regions due to the bolus effect of the thermoplastic head mask

    and the head rest used to aid treatment setup. It is suggested that to achieve the prescription dose at

    the surface 2 mm depth bolus or a custom thermoplastic helmet is used

Publication Date


  • 2008

Citation


  • Hardcastle, N., Soisson, E., Metcalfe, P. E., Rozenfeld, A. & Tomé, W. (2008). Dosimetric verification of helical tomotherapy for total scalp irradiation. Medical Physics, 35 (11), 5061-5068.

Scopus Eid


  • 2-s2.0-54949142565

Ro Metadata Url


  • http://ro.uow.edu.au/engpapers/1798

Number Of Pages


  • 7

Start Page


  • 5061

End Page


  • 5068

Volume


  • 35

Issue


  • 11