MR加速器呼吸导航引导肝癌SBRT的初步临床应用研究  

Preliminary study of clinical application of respiratory navigator‐guided stereotactic body radiation therapy of liver malignancies on magnetic resonance linear accelerator

作　　者：刘敏 廖雄飞 唐斌 杨凤 冯玺 黎杰 王培 郭思川 姚杏红 Liu Min;Liao Xiongfei;Tang Bin;Yang Feng;Feng Xi;Li Jie;Wang Pei;Guo Sichuan;Yao Xinghong(Sichuan Cancer Hospital&Institute,Sichuan Cancer Center,School of Medicine,University of Electronic Science and Technology of China,Radiation Oncology Key Laboratory of Sichuan Province,Chengdu 610041,China;Elekta Beijing Medical Systems Co.Ltd.,Beijing 102000,China)

机构地区：[1]四川省肿瘤医院·研究所/四川省癌症防治中心/电子科技大学医学院/放射肿瘤学四川省重点实验室,成都610041 [2]医科达(北京)医疗器械有限公司,北京102000

出　　处：《中华放射肿瘤学杂志》2022年第12期1133-1139,共7页Chinese Journal of Radiation Oncology

基　　金：四川省肿瘤医院优秀青年基金项目(YB2021030);四川省卫生健康委员会医学科技项目(21PJ116);中华国际医学交流基金会临床研究项目(2019-N-11-24)。

摘　　要：目的初步探讨MR加速器呼吸导航引导肝癌立体定向体部放疗(SBRT)的流程、可行性及应用优势。方法回顾分析2021年9—12月10例使用MR加速器接受呼吸导航引导,行SBRT的肝癌患者临床数据。所有患者均行CT模拟定位和Unity MR定位,采集平扫、增强和4D CT,及T13D、T_(2)3D MR影像。选择4D CT呼气末端图像设计参考计划,治疗前采集呼吸导航(呼气末端)T2 Navigator MR图像,并结合实时监控2D MR影像调整或修改靶区位置和形状,选择合适的在线自适应计划流程。目测定位CT、T_(2)3D MR和T_(2)3D Navigator MR图像显示肿瘤的清晰度;统计靶区体积变化;比较自适应计划和参考计划的剂量学差异;评估患者疗效和不良反应。结果在自由呼吸状态下,T_(2)3D Navigator MR图像质量明显优于常规T_(2)3D MR图像,可更清楚显示肿瘤及其边界。10例患者采用位置适应(ATP)和形状适应(ATS)自适应计划分别为37分次和22分次,3例患者肿瘤消退明显。自适应计划的靶区平均适形指数(CI)与参考计划无差异,但靶区外剂量跌落稍慢(P<0.05),尤其是ATS计划较明显。ATP自适应计划的正常肝平均受量与参考计划基本一致,但平均机器跳数明显增加,且差异有统计学意义(P<0.05)。ATS自适应计划的平均机器跳数、平均子野数和正常肝D_(mean)和V_(10 Gy)比参考计划有所降低,V_(5 Gy)轻微增加,但均无显著差异。7例患者进行放疗后1个月和3个月疗效评价,野内病灶控制较好,放疗不良反应轻微,未见≥3级不良反应。结论MR加速器的呼吸导航提高了自由呼吸状态下肿瘤和MR影像的目测清晰度,在肝脏肿瘤的精准自适应放疗特别是立体定向自适应放疗中展现了优势。Objective To investigate the workflow,feasibility and advantages of respiratory navigator‐guided stereotactic body radiation therapy(SBRT)of liver malignancies on the magnetic resonance linear accelerator(MR‐linac).Methods Clinical data of 10 patients with liver cancer treated with respiratory navigator‐guided SBRT on the MR‐linac from September to December 2021 were analyzed retrospectively.All patients underwent CT and MR simulated localization,and plain,enhanced and 4D CT scan,and T13D MR and T_(2)3D MR images were collected.The expiratory 4D CT was chosen to design the reference plan.The T_(2)3D navigator MR image(end‐exhalation)was collected before treatment,the target position was adjusted or the target shape was modified in combination with the real‐time monitoring 2D MR image and appropriate online adaptive planning process was selected.Then,the ability of CT,T_(2)3D and T_(2)3D navigator MR images to display the tumor was evaluated by naked eye.The changes of target volume were calculated.Dosimetric differences between the adaptive and reference plans were compared.The efficacy and adverse reactions of patients were evaluated.Results In the free breathing state,the T_(2)3D navigator MR image was significantly better than T_(2)3D MR image to clearly display the tumor and its boundary.The adaptive plans of adapt‐to‐position(ATP)and adapt‐to‐shape(ATS)adopted by 10 patients was 37 times and 22 times respectively.The tumor subsided significantly in 3 patients.The average target conformal index(CI)of the adaptive plans was no different from that of the reference plans,but the gradient index(GI)was higher(P<0.05),especially in the ATS plans.Compared to the reference plans,the normal liver V_(5 Gy),V_(10 Gy)and D_(mean)were almost the same,but the average MU was increased with a significant difference in the ATP adaptive plans(P<0.05).The average of MU,segments and normal liver D_(mean)and V_(10 Gy)in the ATS adaptive plans were lower than those in the reference plans,and the liver V_(5 Gy)w

关 键 词：磁共振加速器 呼吸导航 肝脏肿瘤 立体定向放射治疗 

分 类 号：R735.7[医药卫生—肿瘤]