Derivation of TMR from PDD in Absence of Scatter Factors
[摘要] BackgroundandObjectives:TherearesomecomplicationsforTMR(TissueMaximumRatio)calculationinradiotherapytreatmentplanningsystem.ForexampleinTMRcalculationfromPDD(Percentagedepthdose),BSF(BackScatterFactor)ormeasurementisdifficultandinaccurate.ThegoalofthisstudywastocalculateTMRfromPDDinabsenceofscatterfactorsanditsconversiontoacomputersoftwareforpromotionoftreatmentplanningsystem(TPS)inradiotherapydepartments.SubjectsandMethods:MeasurementsofPDDwasperformedusingVarianandSiemensacceleratorsatAhvazGolestanHospitalradiotherapydepartment,byionizationchamberCC13andscanditronixwaterphantom,forboth6and18MVtherapeuticenergies.ThenananalyticalequationforTMRcalculationfromPDDwasdefined.BythisequationTMRvaluesforsquarefieldsindifferentdepthsfor2-50MVtherapeuticenergiesweredetermined.FinallyweemployedMATLABsoftwaretoproduceacomputerprogramtobeusedinTPSsoftware.Result:TherewasagoodagreementbetweenTMRvaluescalculatedbypresentedanalyticalequationandTMRvaluesintheBJR(BritishJournalofRadiology)report.Inmostenergiesfortherapeuticfields,thedifferencebetweenanalyticalandBJRvalueswaslessthan2%fordepthsupto10cm,andlessthan4%fordepthsupto20cm.Conclusion:ThepresentedanalyticalequationcanquickcalculateandquantifyTMRforalltherapeuticfieldsandenergies.
[发布日期] [发布机构]
[效力级别] [学科分类] 基础医学
[关键词] [时效性]
