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Multi-institutional comparison of simulated treatment delivery errors in ssIMRT, manually planned VMAT and autoplan-VMAT plans for nasopharyngeal radiotherapy

Journal Article


Abstract


  • Purpose

    To quantify the impact of simulated errors for nasopharynx radiotherapy across multiple institutions and planning techniques (auto-plan generated Volumetric Modulated Arc Therapy (ap-VMAT), manually planned VMAT (mp-VMAT) and manually planned step and shoot Intensity Modulated Radiation Therapy (mp-ssIMRT)).

    Methods

    Ten patients were retrospectively planned with VMAT according to three institution’s protocols. Within one institution two further treatment plans were generated using differing treatment planning techniques. This resulted in mp-ssIMRT, mp-VMAT, and ap-VMAT plans. Introduced treatment errors included Multi Leaf Collimator (MLC) shifts, MLC field size (MLCfs), gantry and collimator errors. A change of more than 5% in most selected dose metrics was considered to have potential clinical impact. The original patient plan total Monitor Units (MUs) were correlated to the total number of dose metrics exceeded.

    Results

    The impact of different errors was consistent, with ap-VMAT plans (two institutions) showing larger dose deviations than mp-VMAT created plans (one institution). Across all institutions’ VMAT plans the significant errors included; ±5° for the collimator angle, ±5 mm for the MLC shift and +1, ±2 and ±5 mm for the MLC field size. The total number of dose metrics exceeding tolerance was positively correlated to the VMAT total plan MUs (r = 0.51, p < 0.001), across all institutions and techniques.

    Conclusions

    Differences in VMAT robustness to simulated errors across institutions occurred due to planning method differences. Whilst ap-VMAT was most sensitive to MLC errors, it also produced the best quality treatment plans. Mp-ssIMRT was most robust to errors. Higher VMAT treatment plan complexity led to less robust plans.

Authors


  •   Pogson, Elise M. (external author)
  •   Aruguman, Sankar (external author)
  •   Hansen, Christian R. (external author)
  •   Currie, Michael (external author)
  •   Oborn, Brad M.
  •   Blake, Samuel J. (external author)
  •   Juresic, Josip (external author)
  •   Ochoa, Cesar (external author)
  •   Yakobi, Jim (external author)
  •   Haman, Alicia (external author)
  •   Trtovac, Admir (external author)
  •   Carolan, Martin G.
  •   Holloway, Lois C.
  •   Thwaites, David (external author)

Publication Date


  • 2017

Citation


  • Pogson, E. M., Aruguman, S., Hansen, C. R., Currie, M., Oborn, B. M., Blake, S. J., Juresic, J., Ochoa, C., Yakobi, J., Haman, A., Trtovac, A., Carolan, M., Holloway, L. & Thwaites, D. I. (2017). Multi-institutional comparison of simulated treatment delivery errors in ssIMRT, manually planned VMAT and autoplan-VMAT plans for nasopharyngeal radiotherapy. Physica Medica: an international journal devoted to the applications of physics to medicine and biology, 42 55-66.

Scopus Eid


  • 2-s2.0-85035112720

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers1/923

Has Global Citation Frequency


Number Of Pages


  • 11

Start Page


  • 55

End Page


  • 66

Volume


  • 42

Place Of Publication


  • United Kingdom

Abstract


  • Purpose

    To quantify the impact of simulated errors for nasopharynx radiotherapy across multiple institutions and planning techniques (auto-plan generated Volumetric Modulated Arc Therapy (ap-VMAT), manually planned VMAT (mp-VMAT) and manually planned step and shoot Intensity Modulated Radiation Therapy (mp-ssIMRT)).

    Methods

    Ten patients were retrospectively planned with VMAT according to three institution’s protocols. Within one institution two further treatment plans were generated using differing treatment planning techniques. This resulted in mp-ssIMRT, mp-VMAT, and ap-VMAT plans. Introduced treatment errors included Multi Leaf Collimator (MLC) shifts, MLC field size (MLCfs), gantry and collimator errors. A change of more than 5% in most selected dose metrics was considered to have potential clinical impact. The original patient plan total Monitor Units (MUs) were correlated to the total number of dose metrics exceeded.

    Results

    The impact of different errors was consistent, with ap-VMAT plans (two institutions) showing larger dose deviations than mp-VMAT created plans (one institution). Across all institutions’ VMAT plans the significant errors included; ±5° for the collimator angle, ±5 mm for the MLC shift and +1, ±2 and ±5 mm for the MLC field size. The total number of dose metrics exceeding tolerance was positively correlated to the VMAT total plan MUs (r = 0.51, p < 0.001), across all institutions and techniques.

    Conclusions

    Differences in VMAT robustness to simulated errors across institutions occurred due to planning method differences. Whilst ap-VMAT was most sensitive to MLC errors, it also produced the best quality treatment plans. Mp-ssIMRT was most robust to errors. Higher VMAT treatment plan complexity led to less robust plans.

Authors


  •   Pogson, Elise M. (external author)
  •   Aruguman, Sankar (external author)
  •   Hansen, Christian R. (external author)
  •   Currie, Michael (external author)
  •   Oborn, Brad M.
  •   Blake, Samuel J. (external author)
  •   Juresic, Josip (external author)
  •   Ochoa, Cesar (external author)
  •   Yakobi, Jim (external author)
  •   Haman, Alicia (external author)
  •   Trtovac, Admir (external author)
  •   Carolan, Martin G.
  •   Holloway, Lois C.
  •   Thwaites, David (external author)

Publication Date


  • 2017

Citation


  • Pogson, E. M., Aruguman, S., Hansen, C. R., Currie, M., Oborn, B. M., Blake, S. J., Juresic, J., Ochoa, C., Yakobi, J., Haman, A., Trtovac, A., Carolan, M., Holloway, L. & Thwaites, D. I. (2017). Multi-institutional comparison of simulated treatment delivery errors in ssIMRT, manually planned VMAT and autoplan-VMAT plans for nasopharyngeal radiotherapy. Physica Medica: an international journal devoted to the applications of physics to medicine and biology, 42 55-66.

Scopus Eid


  • 2-s2.0-85035112720

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers1/923

Has Global Citation Frequency


Number Of Pages


  • 11

Start Page


  • 55

End Page


  • 66

Volume


  • 42

Place Of Publication


  • United Kingdom