Dose Uncertainties in IMPT for Oropharyngeal Cancer in the Presence of Anatomical, Range, and Setup Errors
A.C. Kraan,Steven van de Water,David N. Teguh,Abrahim Al-Mamgani,T Madden,Hanne M. Kooy,Ben J.M. Heijmen,Mischa S. Hoogeman +7 more
TLDR
For oropharyngeal cancer patients, treatment uncertainties can result in significant differences between planned and delivered IMPT doses, and repeat diagnostic CT scans during treatment, recalculation of the dose, and if required, adaptive planning to improve adequate IMPT dose delivery are advised.Abstract:
Purpose Setup, range, and anatomical uncertainties influence the dose delivered with intensity modulated proton therapy (IMPT), but clinical quantification of these errors for oropharyngeal cancer is lacking. We quantified these factors and investigated treatment fidelity, that is, robustness, as influenced by adaptive planning and by applying more beam directions. Methods and Materials We used an in-house treatment planning system with multicriteria optimization of pencil beam energies, directions, and weights to create treatment plans for 3-, 5-, and 7-beam directions for 10 oropharyngeal cancer patients. The dose prescription was a simultaneously integrated boost scheme, prescribing 66 Gy to primary tumor and positive neck levels (clinical target volume-66 Gy; CTV-66 Gy) and 54 Gy to elective neck levels (CTV-54 Gy). Doses were recalculated in 3700 simulations of setup, range, and anatomical uncertainties. Repeat computed tomography (CT) scans were used to evaluate an adaptive planning strategy using nonrigid registration for dose accumulation. Results For the recalculated 3-beam plans including all treatment uncertainty sources, only 69% (CTV-66 Gy) and 88% (CTV-54 Gy) of the simulations had a dose received by 98% of the target volume (D98%) >95% of the prescription dose. Doses to organs at risk (OARs) showed considerable spread around planned values. Causes for major deviations were mixed. Adaptive planning based on repeat imaging positively affected dose delivery accuracy: in the presence of the other errors, percentages of treatments with D98% >95% increased to 96% (CTV-66 Gy) and 100% (CTV-54 Gy). Plans with more beam directions were not more robust. Conclusions For oropharyngeal cancer patients, treatment uncertainties can result in significant differences between planned and delivered IMPT doses. Given the mixed causes for major deviations, we advise repeat diagnostic CT scans during treatment, recalculation of the dose, and if required, adaptive planning to improve adequate IMPT dose delivery.read more
Citations
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Investigating CT to CBCT image registration for head and neck proton therapy as a tool for daily dose recalculation.
Guillaume Landry,R. Nijhuis,George Dedes,Josefine Handrack,Christian Thieke,Guillaume Janssens,Jonathan Orban de Xivry,Michael Reiner,Florian Kamp,Jan J. Wilkens,Chiara Paganelli,Marco Riboldi,Guido Baroni,Ute Ganswindt,Claus Belka,Katia Parodi +15 more
TL;DR: This work investigated deformable image registration (DIR) of the planning CT (pCT) to the CBCT to generate a virtual CT (v CT) to be used for proton dose recalculation and generated CBCT based stopping power distributions using DIR of the pCT to a CBCT scan.
Journal ArticleDOI
Proton therapy for head and neck cancer: expanding the therapeutic window
Jonathan E. Leeman,Paul B. Romesser,Ying Zhou,Sean McBride,Nadeem Riaz,Eric J. Sherman,Marc Cohen,Oren Cahlon,Nancy Y. Lee +8 more
TL;DR: The role of proton beam therapy is attempted to be defined in the contemporary multidisciplinary management of various types of head and neck cancer.
Journal ArticleDOI
Intensity modulated proton therapy (IMPT) – The future of IMRT for head and neck cancer
Amy C. Moreno,Steven J. Frank,Adam S. Garden,David I. Rosenthal,Clifton D. Fuller,Gary Brandon Gunn,Jay Reddy,William H. Morrison,Tyler D. Williamson,Emma B. Holliday,Jack Phan,Pierre Blanchard +11 more
TL;DR: A systematic approach towards utilizing IMPT and additional prospective studies are necessary in order to more accurately estimate the clinical benefit of IMPT over IMRT and passive proton therapy on a case-by-case basis for patients with sub-site specific HNCs.
Journal ArticleDOI
Practical robustness evaluation in radiotherapy - A photon and proton-proof alternative to PTV-based plan evaluation
Erik W Korevaar,Steven J. M. Habraken,D. Scandurra,Roel G J Kierkels,Mirko Unipan,Martijn G C Eenink,Roel J H M Steenbakkers,Stephanie G Peeters,Jaap D. Zindler,Mischa S. Hoogeman,Johannes A. Langendijk +10 more
TL;DR: A practical approach to robustness evaluation was provided and clinically implemented for PTV-less photon and proton treatment planning, consistent with PTV evaluations but without its static dose cloud approximation.
Journal ArticleDOI
Feasibility of MRI-only treatment planning for proton therapy in brain and prostate cancers: Dose calculation accuracy in substitute CT images
TL;DR: It is demonstrated that proton therapy dose calculations on heterogeneous sCTs are in good agreement with plans generated with standard planning CT, and an MRI-only based RTP workflow is feasible in IMPT for brain tumors and prostate cancers.
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TL;DR: DDE and MDE analysis of all IMPT plans demonstrate that the 3D approach is generally more robust to both inter-fraction and inter-field motions than the DET approach, but that strong in-field dose gradients can also adversely affect a plan's robustness.