乳腺癌不同切线野照射法的正常组织剂量对比

Dosimetric comparison of different tangential beam for breast cancer

目的应用常规射野技术与正向调强技术对乳腺癌保乳术后切线野治疗计划进行剂量学对比,分析使用不同照射方法对正常组织受量的影响。方法选取10例左侧乳腺癌保乳术后患者,分别使用模拟模拟机(Sim)照射、常规三维照射(3D-CRT)和正向调强照射方法(FIMRT)进行计划设计。用剂量-体积直方图(DVH)比较各种计划中全肺V20、心脏V15以及患侧胸壁皮肤V105%的剂量学差异。结果FIMRT、3D-CRT和模拟Sim照射法的靶区覆盖率相似,分别为98.5%、98.3%和97.8%(P=0.41);全肺V20体积百分比依次为22.20%、16.64%和24.83%(P=0.001);心脏V15体积百分比依次为12.14%、4.68%和12.38%(P=0.001);3D-CRT计划减少肺V20和心脏V15有明显优势。皮肤V105%体积百分比依次为0.65%、8.23%和16.06%,FIMRT的优势更明显(P=0.001)。结论FIMRT方法可以显著减少皮肤受量,改善剂量均匀性,但不能减少全肺和心脏的受量。3D-CRT对保护患者肺及心脏有明显优势。

Objective To compare the dosimetry for intact breast cancer radiotherapy of simulating 2D radiotherapy（2D-Sim）,3D conventional radiotherapy（3D-CRT） and forward intensity modulated radiotherapy（FIMRT） and to analyze the accepted dose of organ at risks in three different methods. Methods Ten left side breast caner patients were selected,and three methods of 2D-Sim,3D-CRT and FIMRT were used.Dose volume histograms（DVH） were used to compare the volume percentage of all lung receiving more than 20 Gy（V20）,of heart receiving more than 15 Gy（V15） and of skin receiving more than 105% prescribed dose（V105%）. Results The planning target volume（PTV） coverage of FIMRT,3D-CRT and 2D-Sim were 98.5%,98.3% and 97.8%,respectively（P=0.41）. The V20 was 22.20%,16.64% and 24.83%,respectively（P=0.001）.The V15 was 12.14%,4.68% and 12.38%,respectively（P=0.001）.A amelioration of V20 and V15 reduction in 3D-CRT plans was observed.The skin V105% was 0.65%,8.23% and 16.06% respectively,and the advantage in FIMRT was obvious（P=0.001）. Conclusion FIMRT significantly improves the skin uniformity,but doesn＇t reduce the accepted dose of all lung and heart.3D-CRT has a amelioration of lung and heart accepted dose for breast cancer.