Proton relative biological effectiveness (RBE) for survival in mice after thoracic irradiation with fractionated doses

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dc.contributor.authorGueulette J.
dc.contributor.authorBohm L.
dc.contributor.authorSlabbert J.P.
dc.contributor.authorDe Coster B.M.
dc.contributor.authorRutherfoord G.S.
dc.contributor.authorRuifrok A.
dc.contributor.authorOctave-Prignot M.
dc.contributor.authorBinns P.J.
dc.contributor.authorSchreuder A.N.
dc.contributor.authorSymons J.E.
dc.contributor.authorScalliet P.
dc.contributor.authorJones D.T.L.
dc.date.accessioned2011-05-15T16:16:44Z
dc.date.available2011-05-15T16:16:44Z
dc.date.issued2000
dc.description.abstractPurpose: This study aims at providing relative biological effectiveness (RBE) data under reference conditions accounting for the determination of the 'clinical RBE' of protons.Methods and Materials: RBE (ref. 60Co γ-rays) of the 200 MeV clinical proton beam produced at the National Accelerator Centre (South Africa) was determined for lung tolerance assessed by survival after selective irradiation of the thorax in mice. Irradiations were performed in 1, 3, or 10 fractions separated by 12 h. Proton irradiations were performed at the middle of a 7-cm spread out Bragg peak (SOBP). Control γ irradiations were randomized with proton irradiations and performed simultaneously. A total of 1008 mice was used, of which 96 were assessed for histopathology.Results: RBEs derived from LD50 ratios were found not to vary significantly with fractionation (corresponding dose range, ~2-20 Gy). They, however, tend to increase with time and reach (mean of the RBEs for 1, 3 and 10 fractions) 1.00, 1.08, 1.14, and 1.25 for LD50 at 180, 210, 240, and 270 days, respectively (confidence interval approximately 20%). α/β ratios for protons and γ are very similar and average 2.3 (0.6-4.8) for the different endpoints. Additional irradiations in 10 fractions at the end of the SOBP were found slightly more effective (~6%) than at the middle of the SOBP. A control experiment for intestinal crypt regeneration in mice was randomized with the lung experiment and yielded an RBE of 1.14 ± 0.03, i.e., the same value as obtained previously, which vouches for the reliability of the experimental procedure.Conclusion: There is no need to raise the clinical RBE of protons in consideration of the late tolerance of healthy tissues in the extent that RBE for lung tolerance was found not to vary with fractionation nor to differ significantly from those of the majority of early- and late-responding tissues. Copyright (C) 2000 Elsevier Science Inc.
dc.description.versionArticle
dc.identifier.citationInternational Journal of Radiation Oncology Biology Physics
dc.identifier.citation47
dc.identifier.citation4
dc.identifier.issn03603016
dc.identifier.other10.1016/S0360-3016(00)00535-6
dc.identifier.urihttp://hdl.handle.net/10019.1/13916
dc.subjectanimal experiment
dc.subjectanimal model
dc.subjectanimal tissue
dc.subjectarticle
dc.subjectcontrolled study
dc.subjectfemale
dc.subjectfractionation
dc.subjectgamma irradiation
dc.subjectLD 50
dc.subjectmale
dc.subjectmortality
dc.subjectmouse
dc.subjectnonhuman
dc.subjectpriority journal
dc.subjectproton radiation
dc.subjectradiation dose
dc.subjectradiation injury
dc.subjectradiation pneumonia
dc.subjectrelative biologic effectiveness
dc.subjectthorax radiography
dc.subjecttissue reaction
dc.subjectAnimals
dc.subjectConfidence Intervals
dc.subjectDose Fractionation
dc.subjectDose-Response Relationship, Radiation
dc.subjectFemale
dc.subjectLung
dc.subjectMice
dc.subjectMice, Inbred BALB C
dc.subjectProtons
dc.subjectRadiation Tolerance
dc.subjectRadiobiology
dc.subjectRelative Biological Effectiveness
dc.titleProton relative biological effectiveness (RBE) for survival in mice after thoracic irradiation with fractionated doses
dc.typeArticle
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