CT模拟在乳腺癌放射治疗布野中的应用

CT simulation(CT-Sim)in radiotherapy of breast cancer

目的 评价CT模拟在乳腺癌放射治疗布野中的应用价值。方法 患者采取热塑记忆体膜固定 ,魔十字 (MagicCross)丝标记激光定位点 ,CT影像数字化 1:1传输至治疗计划工作站。射线束观视(BEV)下设置乳腺切线野、腋锁野等 ,调整机架、机头及床角大小、射野大小和等中心位置直到所包括的范围满意为止。BEV下直接勾画铅挡块进行铅挡修饰 ,确保射野之间的衔接不出现重叠。根据治疗计划计算出的各射野等中心点的参考坐标数值 ,在激光灯下移动治疗床 ,标记各射野中心点。结果 通过在常规X线模拟机下对照射野位置进行验证 ,虚拟模拟计划 (射野之间的衔接等 )与临床要求完全一致。治疗计划显示通过各种参数的调整及修饰 (挡块、楔形等 ) ,剂量分布符合临床要求。结论 CT模拟可以很好地实现非共面射野之间的衔接并通过各种修饰获得满意的剂量分布 ,该方法简便易行 ,提高了定位精度 。

Obective To explore the value of CT simulation(CT-Sim)in radiotherapy of breast cancer Methods All patients were immobilized in a thermoplastic cast in asupine position.CT scans,typicallywith 5mm slice spacing,were taken in all patients.3-D radiation therapy treatment planning system(STAR-2000) was used All beam arrangements were designed using 3-D visualization and beam's eye view(BEV) Block and wedge modifying was performed.'MaSiC Cross'marker was used to calculate the coordinate of beam's isocenter.Results Verification in simulator and CT showed that the all beam arrangements in CT-Sim meet clinical requirements.Conclusion CT-Sim can achieve better radiation field arrangements,which is easy,simple and accurate and can be routinely used.