磁共振加速器ATP模式颅内肿瘤靶区和危及器官外放研究  

Methodological establishment of PTV and PRV margins for MRI guided online adapt-to-position radiotherapy for intracranial tumors

作　　者：管秋 刘楠 连欣 董婷婷 孙玉亮 梁皓 田蔚 于浪 杨波 邱杰 Guan Qiu;Liu Nan;Lian Xin;Dong Tingting;Sun Yunliang;Liang Hao;Tian Wei;Yu Lang;Yang Bo;Qiu Jie(Departments of Radiation Oncology,Peking Union Medical College Hospital,Chinese Academy of Medical Sciences&Peking Union Medical College,Beijing100730,China)

机构地区：[1]中国医学科学院、北京协和医学院、北京协和医院放射治疗科,北京100730

出　　处：《中华放射肿瘤学杂志》2024年第12期1106-1111,共6页Chinese Journal of Radiation Oncology

基　　金：中央高水平医院临床科研业务费(2022-PUMCH-B-116)。

摘　　要：目的探索Unity磁共振加速器(MRL)采用位置自适应(ATP)模式对颅内肿瘤患者进行放射治疗时,可涵盖旋转误差的靶区和危及器官外放的方法。方法回顾性分析2023年11月至2024年1月于北京协和医院接受ATP模式治疗的6例(共150分次)颅内肿瘤患者资料。将定位CT与各分次MR影像进行六维配准并拷贝结构集,再根据治疗时两者三维配准结果,将所有分次影像上的结构集回溯至CT上,对各结构进行取合集处理生成涵盖累计旋转偏差的新结构,计算该结构以原始CT对应结构为基准的各向距离取最大值作为外放结果,同时分析不同患者外放结果和肿瘤所处颅内位置的关系。组间差异采用方差分析,两组样本差异采用后验Wilcoxon检验。结果6例患者靶区的变化范围在左、右(L/R),腹、背(A/P),头、脚(S/I)6个方向上分别为(1.24±0.86)、(1.91±1.07)、(2.02±1.26)、(1.66±1.07)、(1.84±1.84)、(2.94±1.93)mm,其中SI方向结果差异较大,2例患者I方向值超过4 mm,靶区外放结果为3.01 mm/2.4 mm(A/P)、1.9 mm/2.93 mm(L/R)和3.14 mm/4.62 mm(S/I);晶状体L/R方向和视神经S/I方向变化较明显,脑干在A/P方向上的变化为(3.99±4.64)mm。靶区位于颅后位置(左下、右下区)时,可能需要更大的外放值。结论磁共振引导颅内肿瘤ATP模式下,旋转偏差、器官运动以及所处颅内位置均影响靶区和危及器官外放,基于图像配准的方式生成外放可涵盖上述因素,为该技术提供合理的外放值。Objective To establish a method for obtaining planning target volume(PTV)and planning risk volume(PRV)margins caused by rotation in the use of adapt-to-position(ATP)modality of magnetic resonance linear accelerator(MRL)for patients with intracranial tumors.Methods Clinical data of 6 patients with intracranial tumors(150 fractions in total)who received MRI-guided online ATP radiotherapy in Peking Union Medical College Hospital from November 2023 to January 2024 were retrospectively analyzed.The pre-planned CT structure was copied onto each segmented MR image and then the structures were traced back to the CT image according to the three-dimensional registration relationship.The anisotropic distance of the structure based on the original CT structure was calculated to obtain the variation range of the target and the organs at risk.The maximum anisotropic value was taken as the result of the PTV and the relationship between the results and intracranial location of different patients was analyzed.Group comparison was performed by Chi-square test.Two group comparison was conducted by post-hoc Wilcoxon signed-rank test.Results After the rotation deviation was included,the range of target changes in the six directions of left and right(L/R),anterior and posterior(A/P)and superior and inferior(S/I)of the 6 patients were:(1.24±0.86)mm/(1.91±1.07)mm,(2.02±1.26)mm/(1.66±1.07)mm,(1.84±1.84)mm/(2.94±1.93)mm,respectively.The results in the SI direction were significantly different,and the values in the I direction in 2 patients exceeded 4 mm,the margins suitable for all patients were 3.01 mm/2.4 mm(A/P),1.9 mm/2.93 mm(L/R)and 3.14 mm/4.62 mm(S/I)in different directions,respectively.The L/R direction of the lens and the S/I direction of the optic nerve were significantly changed,and the A/P direction of the brain stem was(3.99±4.64)mm.Larger values might be required when the target was in the posterior brain(left-down area,right-down area).Conclusions The rotation deviation,organ movement and intracranial location affect

关 键 词：脑肿瘤 磁共振加速器 位置自适应 边界外放 图像配准 

分 类 号：R739.41[医药卫生—肿瘤]