title: Benchmarking of a treatment planning system for spot scanning proton therapy: comparison and analysis of robustness to setup errors of photon IMRT and proton SFUD treatment plans of base of skull meningioma.
abstract: OBJECTIVE
  Base of skull meningioma can be treated with both intensity modulated radiation therapy (IMRT) and spot scanned proton therapy (PT). One of the main benefits of PT is better sparing of organs at risk, but due to the physical and dosimetric characteristics of protons, spot scanned PT can be more sensitive to the uncertainties encountered in the treatment process compared with photon treatment. Therefore, robustness analysis should be part of a comprehensive comparison between these two treatment methods in order to quantify and understand the sensitivity of the treatment techniques to uncertainties. The aim of this work was to benchmark a spot scanning treatment planning system for planning of base of skull meningioma and to compare the created plans and analyze their robustness to setup errors against the IMRT technique.
  
  
  METHODS
  Plans were produced for three base of skull meningioma cases: IMRT planned with a commercial TPS [Monaco (Elekta AB, Sweden)]; single field uniform dose (SFUD) spot scanning PT produced with an in-house TPS (PSI-plan); and SFUD spot scanning PT plan created with a commercial TPS [XiO (Elekta AB, Sweden)]. A tool for evaluating robustness to random setup errors was created and, for each plan, both a dosimetric evaluation and a robustness analysis to setup errors were performed.
  
  
  RESULTS
  It was possible to create clinically acceptable treatment plans for spot scanning proton therapy of meningioma with a commercially available TPS. However, since each treatment planning system uses different methods, this comparison showed different dosimetric results as well as different sensitivities to setup uncertainties. The results confirmed the necessity of an analysis tool for assessing plan robustness to provide a fair comparison of photon and proton plans.
  
  
  CONCLUSIONS
  Robustness analysis is a critical part of plan evaluation when comparing IMRT plans with spot scanned proton therapy plans.
authors.affiliation: St James's Institute of Oncology, Medical Physics and Engineering, Leeds LS9 7TF, United Kingdomand Abertawe Bro Morgannwg University Health Board, Medical Physics and Clinical Engineering, Swansea SA2 8QA, United Kingdom.
authors.forename: R
authors.initials: R
authors.lastname: Harding
authors.affiliation: Paul Scherrer Institute, Centre for Proton Therapy, Villigen 5232, Switzerland.
authors.forename: P
authors.initials: P
authors.lastname: Trnková
authors.affiliation: St James's Institute of Oncology, Medical Physics and Engineering, Leeds LS9 7TF, United Kingdom.
authors.forename: S J
authors.initials: SJ
authors.lastname: Weston
authors.affiliation: St James's Institute of Oncology, Medical Physics and Engineering, Leeds LS9 7TF, United Kingdom.
authors.forename: J
authors.initials: J
authors.lastname: Lilley
authors.affiliation: St James's Institute of Oncology, Medical Physics and Engineering, Leeds LS9 7TF, United Kingdom.
authors.forename: C M
authors.initials: CM
authors.lastname: Thompson
authors.affiliation: Leeds Institute of Molecular Medicine, Oncology and Clinical Research, Leeds LS9 7TF, United Kingdomand St James's Institute of Oncology, Oncology, Leeds LS9 7TF, United Kingdom.
authors.forename: S C
authors.initials: SC
authors.lastname: Short
authors.affiliation: St James's Institute of Oncology, Oncology, Leeds LS9 7TF, United Kingdom.
authors.forename: C
authors.initials: C
authors.lastname: Loughrey
authors.affiliation: St James's Institute of Oncology, Medical Physics and Engineering, Leeds LS9 7TF, United Kingdom.
authors.forename: V P
authors.initials: VP
authors.lastname: Cosgrove
authors.affiliation: Paul Scherrer Institute, Centre for Proton Therapy, Villigen 5232, Switzerland.
authors.forename: A J
authors.initials: AJ
authors.lastname: Lomax
authors.affiliation: St James's Institute of Oncology, Medical Physics and Engineering, Leeds LS9 7TF, United Kingdomand Institute of Medical Physics, School of Physics, University of Sydney, Sydney NSW 2006, Australia.
authors.forename: D I
authors.initials: DI
authors.lastname: Thwaites
mesh_terms: D000465:Algorithms; D019985:Benchmarking; D001859:Bone Neoplasms / Q000532:radiotherapy*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008579:Meningioma / Q000532:radiotherapy*; D064847:Multimodal Imaging; D061766:Proton Therapy / Q000379:methods*; D011874:Radiometry; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods; D015203:Reproducibility of Results; D012886:Skull / Q000473:pathology*; D014057:Tomography, X-Ray Computed / Q000379:methods