Dosimetry differences between IMRT and Hybrid techniques after left breast-conserving therapy
Objective To compare the dosimetry differences between intensity-modulated radiation therapy(IMRT)and Hybrid techniques after left breast-conserving surgery.Methods Thirty patients accepted CT examination via abdominal deep inspiration breath holding after left breast-conserving surgery.Then two radiotherapy plans including IMRT and Hybrid techniques were designed for each patient according to CT images,and the dosimetry parameters of the planned target area and organ at risk were compared.Results There were no statistical differences in the mean dose(Dmean)of planned target area,Dmean and volume percentage receiving 5 Gy(V5)of heart and V40 of left anterior descending coronary artery(LAD)between the two radiotherapy plans(P＞0.05).The homogeneity index,conformity index and monitor unit of radiotherapy plan using IMRT technique were higher,while the Dmean,V5,V20 and V30 of left lung,maximum dose of heart and Dmean of LAD were lower than those using Hybrid technique(P＜0.05).Conclusion Both radiotherapy plans can meet the dose of target area and limit requirement of organ at risk after left breast-conserving surgery.Relatively,Hybrid technique has a better homogeneity and conformity and less monitor unit in the dose distribution of target area,while IMRT technique is superior in the protection of left lung.
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