Comparing The Dosimetry Differences Between FIF-IMRT And 5-fields-IMRT For Left Breast Cancer After Breast-conserving Surgery

Objective Comparing the dosimetry differences between FIF-IMRT and 5 fields-IMRT for left breast cancer cases that have finished breast-conserving surgery.Methods Choosing 31 left breast cancer cases at random order and lay down FIF-IMRT and 5 fields reverse IMRT for each patient. Researcher will conduct self-control study by using Does Volume Histogram(DVH), and comparing the dose differences between PTV and OARs and compare the difference daily dose and fields of the two plans.Results: The target volume of the two methods can both reach the requirement of prescribed dose. FIF-IMRT have higher V95 and lower V105 in PTV, V100 have no difference. And Dmean,Dmax of FIF-IMRT also lower than 5F-IMRT. V5,V20,Dmean for heart in FIF-IMRT is lower,but V30 and Dmax are higher than 5F-IMRT. V5,V13,V20 and Dmena for left lung is lower in FIF-IMRT,but V40 is higher. Dmean,Dmax of cord and right lung both lower in FIF-IMRT. And FIF-IMRT have lower MU and more less fields.Conclusion: All the plans can reach target sections’ dose requirement. But for FIF-IMRT the OAR’s distribution in low-dose area is better than other two plans and have lower MU and more less fields.