图像引导放疗在58例肺癌患者中的应用观察

目的 观察图像引导放疗(IGRT)在肺癌中的应用价值.方法 搜集近1年内采用IGRT的58例肺癌病例,其中左肺癌22例,右肺癌30例,肺癌纵隔淋巴结转移5例,椎体转移1例.比较摆位前后IGRT数据,比较大体肿瘤体积(GTV)在IGRT图像与模拟定位CT图像的变化.结果 摆位误差在x、y、z轴上分别为(0.02±0.26)、(-0.14±0.49)、(-0.13±0.27)cm和旋转轴上的分别为-0.15°±1.59°、-0.01°±1.50°、0.12°±1.08°.15例IGRT图像显示GTV有移位,其中左上肺最多见有5例.向腹方向移位9例,4例为左上肺病变.23例疗中GTV缩小,其中右上肺10例,左上肺5例.16个病变有在右方向上缩小,其中右上肺7个.22个病变均呈非对称性缩小,GTV平均缩小4.9 cm3.GTV缩小时放疗剂量为4～46 Gy,其中9例为20～30 Gy.结论 IGRT的应用明显减少了肺癌患者放疗摆位误差.IGRT观察到25.9%GTV有移动,44.2%疗中GTV缩小,何时进行靶区修改有待进一步研究.

Image-guided radiotherapy for fifty-eight patients with lung cancer

Objective To study the value of image-guided radiotherapy (IGRT) in lung cancer. Methods From Mar. 2007 to Dec. 2007,58 patients with lung cancer were treated with IGRT. Set-up er-rors in each axial direction was calculated based on IGRT images of each patient. The change of GTV was e-valuated on both cone-beam CT and CT simulator images. Results Twenty-two patients with left lung cane-er,30 with right lung cancer,5 with mediastinal lymphanode metastasis and one with vertebra metastasis were included. The set-up error in x,y and z axes was (0.02±0.26) cm, (0.14±0.49) cm and ( -0. 13± 0.27) cm, respectively,while the rotary set-up error in each axis was -0.15°± 1.59°, -0.01°± 1.50° and 0.12°±1.08°, respectively. The set-up errors were siguifieantly decreased by using of IGRT. GTV movement was observed in 15 patients (25.9%) ,including 5 with left upper lung cancer. GTV moving to the anterior direction was observed in 9 patients,including 4 with]eft upper lung cancer. GTV reduced in 23 (44.2%) patients during treatment. Asymmetric GTV reduction of 22 lesions was observed,with a mean re-ductive volume of 4.9 cm3. When GTV began to shrink,the irradiation dose was 4 -46 Gy,with 20 -30 Gy in 9 patients. Conclusions The use of IGRT can significantly reduce set-up errors. GTV movement and reduction are observed in some cases. The time to modify the target volume needs to be further studied.