乳腺癌根治术后特定射野固定钨门分野静态IMRT与VMAT的临床剂量学评估

目的 比较乳腺癌根治术后患者特定射野固定钨门静态调强放疗(Intensity Modulated Radiation Therapy,IMRT)与容积旋转调强放疗(Volumetric Modulated Arc Therapy,VMAT)的剂量学差异.方法 选择24例乳腺癌根治术后患者,分别设计IMRT计划与VMAT...

Clinical Dosimetry Evaluation of Static IMRT with Fixed Jaws in Specific Field and VMAT for Breast Cancer after Radical Mastectomy

Objective To compare the dosimetric difference between static intensity modulated radiation therapy(IMRT)with fixed jaws in specific field and volumetric modulated arc therapy(VMAT)in patients with breast cancer after radical mastectomy.Methods A total of 24 patients with breast cancer after radical mastectomy were selected.IMRT plans and VMAT plans were designed respectively.In the IMRT plans,the supraclavicular area and chest wall area were irradiated by fixed jaw technology in specific fields.The dose parameters of the target areas and organs at risk,the number of machine units and the verification pass rate were compared between the two groups.Results The results of CI and HI in target area of the VMAT plan were better than those of the IMRT plan(P<0.05).The volume parameters in low-dose areas below V₅ of contralateral lung in VMAT plan were higher than those in IMRT plan,while the volume parameters of the high-dose area of the affected lung tissue above V₁₀ was significantly lower than the IMRT plan(P<0.05).Heart:the parameters of V5 and above in the VMRT plan for patients with left breast cancer were lower than the IMRT plan.On the other hand,the cardiac parameters of the right breast cancer showed an opposite trend.The average MUs of the VMAT plan was less than that of the IMRT plan,especially for patients with left breast cancer,with significant difference(t=4.18,P<0.05).Conclusion For patients after radical mastectomy for breast cancer,both IMRT plan with fixed jaw in specific field and VMAT plan can meet the clinical needs.The VMAT plan has better target area conformity and uniformity than the IMRT plan,while reduced exposure volume of the high-dose area in lung tissue and other organ at risk,but increased the irradiated range of the lowdose area;at the same time,decreased MUs and shortened the treatment time.