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Case report
peer-reviewed

Robust Planning for a Patient Treated in Decubitus Position with Proton Pencil Beam Scanning Radiotherapy



Abstract

A challenging case was reported for a patient treated in decubitus position with proton pencil beam scanning. A regular robust plan with the consideration of the uncertainties of translational alignment and range accuracy cannot ensure the target coverage as revealed in two verification computed tomography (CT) scans during the first week of the treatment. The irreproducibility of daily alignment and anatomical variations in such a position is mainly due to patient’s roll. To mitigate the interfractional effect on the target coverage, a novel robust optimization against the patient’s angular setup uncertainties was implemented to improve the plan quality by introducing two artificial CT image sets by rolling the planning CT three degrees in both clockwise and counter-clockwise directions and adding them into robust optimization scenarios, which was shown to be an effective and simple way to mitigate target dose degradation with respect to interfractional variations. This method can be easily generalized and applied to other situations where angular variations in patient’s setup can introduce large dosimetric effects. It is recommended that angularly robust optimization method should be integrated into the treatment planning system as an option particularly for patient’s treatment subject to large angular variations, such as the one in the decubitus position reported here.



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Case report
peer-reviewed

Robust Planning for a Patient Treated in Decubitus Position with Proton Pencil Beam Scanning Radiotherapy


Author Information

Shikui Tang Corresponding Author

Physics, Texas Center for Proton Therapy

Limin Song

Physics, Texas Center for Proton Therapy

Jared D. Sturgeon

Physician, Texas Center for Proton Therapy

Chang Chang

Medical Physics, Texas Center for Proton Therapy


Ethics Statement and Conflict of Interest Disclosures

Human subjects: Consent was obtained by all participants in this study. Informed consent obtained. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.


Case report
peer-reviewed

Robust Planning for a Patient Treated in Decubitus Position with Proton Pencil Beam Scanning Radiotherapy


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Case report
peer-reviewed

Robust Planning for a Patient Treated in Decubitus Position with Proton Pencil Beam Scanning Radiotherapy

Shikui Tang">Shikui Tang , Limin Song">Limin Song, Jared D. Sturgeon">Jared D. Sturgeon, Chang Chang">Chang Chang

  • Author Information
    Shikui Tang Corresponding Author

    Physics, Texas Center for Proton Therapy

    Limin Song

    Physics, Texas Center for Proton Therapy

    Jared D. Sturgeon

    Physician, Texas Center for Proton Therapy

    Chang Chang

    Medical Physics, Texas Center for Proton Therapy


    Ethics Statement and Conflict of Interest Disclosures

    Human subjects: Consent was obtained by all participants in this study. Informed consent obtained. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.

    Acknowledgements


    Article Information

    Published: September 20, 2017

    DOI

    10.7759/cureus.1706

    Cite this article as:

    Tang S, Song L, Sturgeon J D, et al. (September 20, 2017) Robust Planning for a Patient Treated in Decubitus Position with Proton Pencil Beam Scanning Radiotherapy. Cureus 9(9): e1706. doi:10.7759/cureus.1706

    Publication history

    Received by Cureus: August 08, 2017
    Peer review began: August 17, 2017
    Peer review concluded: September 15, 2017
    Published: September 20, 2017

    Copyright

    © Copyright 2017
    Tang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License CC-BY 3.0., which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

    License

    This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

A challenging case was reported for a patient treated in decubitus position with proton pencil beam scanning. A regular robust plan with the consideration of the uncertainties of translational alignment and range accuracy cannot ensure the target coverage as revealed in two verification computed tomography (CT) scans during the first week of the treatment. The irreproducibility of daily alignment and anatomical variations in such a position is mainly due to patient’s roll. To mitigate the interfractional effect on the target coverage, a novel robust optimization against the patient’s angular setup uncertainties was implemented to improve the plan quality by introducing two artificial CT image sets by rolling the planning CT three degrees in both clockwise and counter-clockwise directions and adding them into robust optimization scenarios, which was shown to be an effective and simple way to mitigate target dose degradation with respect to interfractional variations. This method can be easily generalized and applied to other situations where angular variations in patient’s setup can introduce large dosimetric effects. It is recommended that angularly robust optimization method should be integrated into the treatment planning system as an option particularly for patient’s treatment subject to large angular variations, such as the one in the decubitus position reported here.



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Shikui Tang

Physics, Texas Center for Proton Therapy

For correspondence:
shikui.tang@usoncology.com

Limin Song

Physics, Texas Center for Proton Therapy

Jared D. Sturgeon

Physician, Texas Center for Proton Therapy

Chang Chang, Ph.D.

Medical Physics, Texas Center for Proton Therapy

Shikui Tang

Physics, Texas Center for Proton Therapy

For correspondence:
shikui.tang@usoncology.com

Limin Song

Physics, Texas Center for Proton Therapy

Jared D. Sturgeon

Physician, Texas Center for Proton Therapy

Chang Chang, Ph.D.

Medical Physics, Texas Center for Proton Therapy