An analysis of the advantage of biologically equivalent dose of unconventionally fractionated radiotherapy / 中华放射医学与防护杂志

ABSTRACT

Objective To analyze the advantage of altered fractionation radiotherapy by calculating the accumulative effects of daily biologically effective dose (BED) to find out the difference between conventional fractionated radiotherapy and altered fractionation radiotherapy.Methods The data in the report of hyperfractionated or accelerated radiotherapy for head and neck cancer published by Cochrane Collaboration in 2010 was analyzed.Based on the radiotherapy processes mentioned in this report,the accumulative effects of daily BED were calculated and compared in different radiotherapy processes by using linear-quadratic mode.The variation of BED in different radiotherapy processes was find out.Results In total dose of unity as the premise of 70 Gy,altered fractionation especially the hyperfractionated accelerated radiotherapy could give a higher BED to the tumor during a shorter period,hyperfractionated radiotherapy could give a lower BED to normal tissues,and hyperfractionated radiotherapy with split course could give higher BED to the tumor while lower BED to normal tissues.Conclusions The variation of BED in different radiotherapy processes can be shown clearly by linear-quadratic mode.It can be simple and shortcut through mathematical models for the evaluation of different radiotherapy plan,on clinical symptomatic selection play a guiding role in tumor therapy.