Purpose:Physical dose distribution in radiotherapy treatment plans may not represent a useful clinical tool due to the variation of biological effect of dose fractionation of various tissues.We aimed to develop software program demonstrating dose distributions in Biological Effective Dose(BED)concepts.Methods:The MATLAB based BED distribution software program was designed to import Computed Tomography(CT)images with radiotherapy treatment plans and converted the physical dose distribution to the BED distribution.The BED calculation was based on LQ-L model,and the radiobiological parameters in the program were obtained either from references or users input according to clinical experiences.The accuracy of the program was verified by comparing the BED distribution to manual calculation in varieties of cases in different regions.Results:This software program provided:import of radiotherapy treatment plans,pixel-wise physical dose for BED calculation,and isoBED line on the CT image.Besides radiobiological parameters,some specific data(number of fraction,dose fraction and overall treatment time)can input into the panel.The verification of BED dose distributions in lung,head & neck and oral cases revealed that there were not significantly differences(p = 0.319,p = 0.319 and p = 0.343 respectively)between the program and manual BED calculations.Conclusion :Our in-house BED distribution software program is feasible to use in clinical practice and research work.However it should be applied with cautiousness as the validity of the program depends on the accuracy of the published biological parameters.