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Reference: Jones, B, (2016). Why RBE must be a variable and not a constant in proton therapy. British Journal of Radiology, 89 (1063), Article: 20160116.Citable link to this page:


Why RBE must be a variable and not a constant in proton therapy

Abstract: Purpose: This paper considers why the proton therapy relative biological effect (RBE) should bevariable rather than constant.Methods: The reasons for a variable proton RBE are enumerated, with qualitative and quantitativearguments. The heterogenous data sets collated by Pagenetti et al and the more homogenous data ofBritten et al are further analysed using linear regression fitting and RBE-inclusive adaptations of thelinear quadratic (LQ) radiation model.Results: The in vitro data show RBE increasing as dose per fraction is lowered. In the Paganetti et al(2002) data sets, the differences between observed and expected effects are smaller when the linearquadratic model is used, but with such data heterogeneity firm statistical conclusions cannot beobtained. The more homogeneous data set shows an unequivocal variation in RBE with dose perfaction. The in vivo data are inappropriate for assessments of late normal tissue effects inradiotherapy. Also, if there is the same degree of uncertainty in an RBE of 1.1 or in an RBE of 2-3 for Cions, the fractional and biological effective doses (BED) can vary considerably and be greater in theproton case. So, errors in RBE assignment are important for protons, just as with C ions.Conclusions: Further experimental programmes are proposed, including late normal tissue endpoints.Better RBE allocations might further improve proton therapy outcomes.Advances in Knowledge: This study provides a rigorous critique of the 1.1 RBE used for protons, fromtheoretical and practical standpoints. The data analysis shows that the linear quadratic model is moreappropriate than simple linear regression. Comprehensive research programmes are suggested.

Publication status:PublishedPeer Review status:Peer reviewedVersion:Publisher's versionNotes:Copyright © 2016 Bleddyn Jones. Published by the British Institute of Radiology.

Bibliographic Details

Publisher: British Institute of Radiology

Publisher Website: http://www.bir.org.uk/

Journal: British Journal of Radiologysee more from them

Publication Website: http://www.birpublications.org/loi/bjr/

Volume: 89

Issue: 1063

Extent: Article: 20160116

Issue Date: 2016

pages:Article: 20160116Identifiers

Urn: uuid:bc5095d7-b175-494d-b50a-f58e3cfe9bf1

Source identifier: 615398

Eissn: 1748-880X

Issn: 0007-1285

Doi: https://doi.org/10.1259/bjr.20160116 Item Description

Type: Journal article;

Version: Publisher's version Tiny URL: pubs:615398


Author: Jones, B - institutionUniversity of Oxford Oxford, MSD, Oncology, CRUK-MRC Ox Inst for Radiation Oncology - - - - Bibliographic D

Source: https://ora.ox.ac.uk/objects/uuid:bc5095d7-b175-494d-b50a-f58e3cfe9bf1


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