title: Use of normalized total dose to represent the biological effect of fractionated radiotherapy.
abstract: There are currently a number of radiobiological models to account for the effects of dose fractionation and time. Normalized total dose (NTD) is not another new model but is a previously reported, clinically useful form in which to represent the biological effect, determined by any specific radiobiological dose-fractionation model, of a course of radiation using a single set of standardized, easily understood terminology. The generalized form of NTD reviewed in this paper describes the effect of a course of radiotherapy administered with nonstandard fractionation as the total dose of radiation in Gy that could be administered with a given reference fractionation such as 2 Gy per fraction, 5 fractions per week that would produce an equivalent biological effect (probability of complications or tumor control) as predicted by a given dose-fractionation formula. The use of normalized total dose with several different exponential and linear-quadratic dose-fraction formulas is presented.
authors.affiliation: Department of Radiation Oncology, University of Pittsburgh School of Medicine, Pennsylvania.
authors.forename: J C
authors.initials: JC
authors.lastname: Flickinger
authors.forename: A
authors.initials: A
authors.lastname: Kalend
mesh_terms: D006801:Humans; D015233:Models, Statistical; D011879:Radiotherapy Dosage / Q000592:standards*