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dc.contributor.authorMackay, Ranald I
dc.contributor.authorHendry, Jolyon H
dc.contributor.authorMoore, Christopher J
dc.contributor.authorWilliams, Peter C
dc.contributor.authorRead, G
dc.date.accessioned2010-03-24T15:31:30Z
dc.date.available2010-03-24T15:31:30Z
dc.date.issued1997-05
dc.identifier.citationPredicting late rectal complications following prostate conformal radiotherapy using biologically effective doses and normalized dose-surface histograms. 1997, 70 (833):517-26 Br J Radiolen
dc.identifier.issn0007-1285
dc.identifier.pmid9227235
dc.identifier.urihttp://hdl.handle.net/10541/94923
dc.description.abstractA model to predict the late normal tissue complication probability (NTCP) of the rectum following conformal therapy is described. The model evaluates the biological consequence of inhomogeneities in the physical dose by computing dose histograms of the biologically effective dose to the surface of the rectum for a given fractionation scheme. A method of normalizing the surface area of the rectum is employed so that the predicted NTCP is independent of the differing cross-sectional size of sections of the rectum, ensuring the NTCP is dependent only on the dose delivered to sensitive rectal tissues. The model has been used to assess severe late rectal complications and the milder RTOG grades 2 and 3 reactions. This model was found to predict severe toxicity levels of 1.7 +/- 0.6% for an accelerated treatment of 50 Gy in 16 fractions commonly employed at this centre. This result lies between the severe toxicities predicted for 60 and 62 Gy delivered in 2 Gy fractions. The model predicts that the average NTCP for severe late effects for nine prostate patients becomes greater than 5% with a fractionation scheme of 70 Gy in 35 fractions, for the four fields treatment. The effects of not treating all fields at each therapy session on rectal toxicity were also investigated. Biologically effective dose-surface histograms show that the dose to the lower surface of the rectum is increased by not treating all fields at each therapy session, but the predicted differences in rectal NTCP are negligible.
dc.language.isoenen
dc.subjectProstatic Canceren
dc.subject.meshDose-Response Relationship, Radiation
dc.subject.meshHumans
dc.subject.meshMale
dc.subject.meshPredictive Value of Tests
dc.subject.meshProstatic Neoplasms
dc.subject.meshRadiation Dosage
dc.subject.meshRectal Diseases
dc.subject.meshRectum
dc.subject.meshRelative Biological Effectiveness
dc.titlePredicting late rectal complications following prostate conformal radiotherapy using biologically effective doses and normalized dose-surface histograms.en
dc.typeArticleen
dc.contributor.departmentNorth Western Medical Physics, Christie Hospital NHS Trust, Manchester, UK.en
dc.identifier.journalBritish Journal of Radiologyen
html.description.abstractA model to predict the late normal tissue complication probability (NTCP) of the rectum following conformal therapy is described. The model evaluates the biological consequence of inhomogeneities in the physical dose by computing dose histograms of the biologically effective dose to the surface of the rectum for a given fractionation scheme. A method of normalizing the surface area of the rectum is employed so that the predicted NTCP is independent of the differing cross-sectional size of sections of the rectum, ensuring the NTCP is dependent only on the dose delivered to sensitive rectal tissues. The model has been used to assess severe late rectal complications and the milder RTOG grades 2 and 3 reactions. This model was found to predict severe toxicity levels of 1.7 +/- 0.6% for an accelerated treatment of 50 Gy in 16 fractions commonly employed at this centre. This result lies between the severe toxicities predicted for 60 and 62 Gy delivered in 2 Gy fractions. The model predicts that the average NTCP for severe late effects for nine prostate patients becomes greater than 5% with a fractionation scheme of 70 Gy in 35 fractions, for the four fields treatment. The effects of not treating all fields at each therapy session on rectal toxicity were also investigated. Biologically effective dose-surface histograms show that the dose to the lower surface of the rectum is increased by not treating all fields at each therapy session, but the predicted differences in rectal NTCP are negligible.


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