CT与MRI图像融合在颅内肿瘤三维适形放疗中的应用

CT and MRI image fusion in three-dimensional conformal radiotherapy for cranial carcinoma

目的采用CT与MRI图像融合技术,为颅脑肿瘤三维适形放疗提供更精确地靶区定义。方法对25例脑瘤患者分别使用CT和MRI进行三维适形放疗定位,比较2种图像采集方式确定靶区的不同。以MRI确定的靶区作为大体靶区(GTV),以CT图像提供的CT值进行剂量计算,制定放疗计划。结果25例患者均接受了CT和MRI定位,解剖结构及体表标记均基本重合。其中23例患者CT和MRI扫描后显示病灶数目相同,2例患者显示病灶数目不同。CT比MRI扫描GTV体积增大者10例,缩小者15例。放疗结束后复查颅脑MRI评价疗效,有效率为64.0%。结论CT与MRI融合技术进行三维立体适形放疗定位,提高了GTV确定的精确性,提高了适形放疗的精度。

Objective To investigate the advantage of CT and MRI image fusion in determining the target precisely during 3-dimensional conformal radiotherapy for cranial carcinoma. Methods Twenty-five patients received CT and MRI examination simultaneously for localizing the tumor and defining target before 3-dimensional conformal radiotherapy. The target defined by MRI image was used as gross tumor volume, whereas CT value was used to calculate dose, making plan for radiotherapy. The difference between the target defined by CT and MRI was compared. Results All the 25 patients underwent CT and MRI image fusion for localizing the tumor and defining the target in order to make anatomic symbol and surface symbol superposed. The number of tumor nodual detected by CT was as same as that found by MRI in 23 cases except two. Compared with the GTV defined by MRI image, it was larger in 10 cases by CT image, whereas smaller in 15 cases. The response rate assessed by MRI image was 64. 0% （CR ＋ PR） at the end of radiotherapy. Conclusion CT and MRI image fusion technique is more precise than either by CT or MRI alone in defining the GTV of 3-dimensional conformal radiotherapy for cranial carcinoma.