Experimental assessment of inter-centre variation in stopping-power and range prediction in particle therapy
Authors
Peters, N.Wohlfahrt, P.
Dahlgren, C. V.
de Marzi, L.
Ellerbrock, M.
Fracchiolla, F.
Free, J.
Gomà, C.
Góra, J.
Jensen, M. F.
Kajdrowicz, T.
Mackay, Ranald I
Molinelli, S.
Rinaldi, I.
Rompokos, V.
Siewert, D.
van der Tol, P.
Vermeren, X.
Nyström, H.
Lomax, A
Richter, C.
Affiliation
OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Dresden, GermanyIssue Date
2021
Metadata
Show full item recordAbstract
Purpose: Experimental assessment of inter-centre variation and absolute accuracy of stopping-power-ratio (SPR) prediction within 17 particle therapy centres of the European Particle Therapy Network. Material and methods: A head and body phantom with seventeen tissue-equivalent materials were scanned consecutively at the participating centres using their individual clinical CT scan protocol and translated into SPR with their in-house CT-number-to-SPR conversion. Inter-centre variation and absolute accuracy in SPR prediction were quantified for three tissue groups: lung, soft tissues and bones. The integral effect on range prediction for typical clinical beams traversing different tissues was determined for representative beam paths for the treatment of primary brain tumours as well as lung and prostate cancer. Results: An inter-centre variation in SPR prediction (2σ) of 8.7%, 6.3% and 1.5% relative to water was determined for bone, lung and soft-tissue surrogates in the head setup, respectively. Slightly smaller variations were observed in the body phantom (6.2%, 3.1%, 1.3%). This translated into inter-centre variation of integral range prediction (2σ) of 2.9%, 2.6% and 1.3% for typical beam paths of prostate-, lung- and primary brain-tumour treatments, respectively. The absolute error in range exceeded 2% in every fourth participating centre. The consideration of beam hardening and the execution of an independent HLUT validation had a positive effect, on average. Conclusion: The large inter-centre variations in SPR and range prediction justify the currently clinically used margins accounting for range uncertainty, which are of the same magnitude as the inter-centre variation. This study underlines the necessity of higher standardisation in CT-number-to-SPR conversion.Citation
Peters N, Wohlfahrt P, Dahlgren CV, de Marzi L, Ellerbrock M, Fracchiolla F, et al. Experimental assessment of inter-centre variation in stopping-power and range prediction in particle therapy. Radiotherapy and Oncology. 2021 Oct;163:7–13.Journal
Radiotherapy and OncologyDOI
10.1016/j.radonc.2021.07.019PubMed ID
34329653Additional Links
https://dx.doi.org/10.1016/j.radonc.2021.07.019Type
ArticleLanguage
enae974a485f413a2113503eed53cd6c53
10.1016/j.radonc.2021.07.019