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Use of radiation protraction to escalate biologically effective dose to the treatment target
Author(s) -
Kuperman V. Y.,
Spradlin G. S.
Publication year - 2011
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3656053
Subject(s) - fraction (chemistry) , effective dose (radiation) , dose rate , irradiation , dosimetry , biomedical engineering , materials science , chemistry , nuclear medicine , medicine , radiochemistry , chromatography , physics , nuclear physics
Purpose : The aim of this study is to evaluate how simultaneously increasing fraction time and dose per fraction affect biologically effective dose for the target ( BE D tar) while biologically effective dose for the normal tissue ( BE D nt) is fixed. Methods : In this investigation, BE D tarand BE D ntwere studied by assuming mono‐exponential repair of sublethal damage with tissue dependent repair half‐time. Results : Our results demonstrate that under certain conditions simultaneously increasing fraction time and dose per fraction result in increased BE D tarwhile BE D ntis fixed. The dependence of biologically effective dose on fraction time is influenced by the dose rate. In this investigation we analytically determined time‐varying dose rateR ̃which minimizes BED . Changes in BED with fraction time were compared for constant dose rate and forR ̃ . Conclusions : A number of recent experimental and theoretical studies have demonstrated that slow delivery of radiation (known as radiation protraction) leads to reduced therapeutic effect because of increased repair of sublethal damage. In contrast, our analysis shows that under certain conditions simultaneously increasing fraction time and dose per fraction are radiobiologically advantageous.