Evaluation of robustness to setup and range uncertainties for head and neck patients treated with pencil beam scanning proton therapy

Publication date: Available online 11 February 2016
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): Robert Malyapa, Matthew Lowe, Alessandra Bolsi, Antony J. Lomax, Damien C. Weber, Francesca Albertini
PurposeTo evaluate the robustness of head and neck (H&N) plans, treated using intensity modulated proton therapy (IMPT), to range and setup errors and to establish robustness parameters for the planning of future H&N treatments.Methods and MaterialsTen patients previously treated at XXXX were evaluated in terms of robustness to range and setup errors. Error bar dose distributions were generated for each plan, from which a number of metrics were extracted and used to define a 'robustness database' of acceptable parameters over all analysed plans. Patients were treated in sequentially delivered series and plans evaluated for both the first series and for the combined error over the whole treatment. To demonstrate the application of such a database in the head and neck, for one patient, an alternative treatment plan was generated using a simultaneous integrated boost (SIB) approach, as well as plans of differing numbers of fields.ResultsThe 'robustness database' for the treatment of H&N patients is presented. In an example case, comparison of single and multiple field plans against the database show clear improvements in robustness by using multiple fields. Comparing sequentially delivered series and a simultaneous integrated boost approach for this patient show both to be of comparable robustness, although the SIB approach shows a slightly greater sensitivity to uncertaintiesConclusionsA 'robustness database' has been created for the treatment of H&N patients with IMPT based on previous clinical experience. This will allow for the identification of future plans which may benefit from alternative planning approaches to improve robustness

Teaser

Proton plans can be sensitive to errors such as arise from range and setup uncertainties. The robustness of 10 head and neck patients to these uncertainties was evaluated and a database summarising robustness metrics based on these plans was generated which can be used to guide the planning of such treatments. The application of this database was demonstrated by comparing different planning techniques and evaluating the effect of using a different number of fields.


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