基于实时肿瘤运动状态的四维剂量重建方法在肺癌SBRT中的应用  

Application of a four-dimensional dose reconstruction method based on real-time tumor motion status in stereotactic body radiation therapy for non-small cell lung cancer

作　　者：陈维军 邱礼凤 邵凯南 贾勇士[1] 詹文明[1] 李强[1] 邱凌云[1] 丁洁妮 林白桦[1] 梁晓东 李玉成 CHEN Weijun;QIU Lifeng;SHAO Kainan;JIA Yongshi;ZHAN Wenming;LI Qiang;QIU Lingyun;DING Jieni;LIN Baihua;LIANG Xiaodong;LI Yucheng(Cancer Center,Department of Radiation Oncology,Zhejiang Provincial People's Hospital(People's Hospital of Hangzhou Medical College),Hangzhou 310004,China;不详)

机构地区：[1]浙江省人民医院(杭州医学院附属人民医院)肿瘤中心放疗科,杭州310014

出　　处：《浙江医学》2023年第20期2142-2148,I0004,共8页Zhejiang Medical Journal

基　　金：浙江省医药卫生科技计划项目(2021PY002);浙江省基础公益研究计划项目(GF21H180053)。

摘　　要：目的介绍一种基于治疗中实时肿瘤运动状态的四维剂量重建方法,并使用该方法对已经完成治疗的肺癌立体定向放疗(SBRT)患者进行剂量学重建后的评估。方法使用光学体表追踪系统获取肺癌SBRT技术下治疗时的肿瘤运动状态;基于Python语言计算出患者治疗期间不同四维CT时相上的治疗时间权重;在治疗计划系统中按治疗时间权重重建出患者每一个时相CT下患者的加权剂量;将加权剂量形变配准到平均密度投影CT上,得到患者的实际治疗的四维重建剂量,采用上述方法,序贯选取2022年1月至2023年1月在浙江省人民医院行SBRT治疗的10例早期非小细胞肺癌(NSCLC)患者进行四维剂量学评估,并与传统的三维剂量学评估方法进行剂量学参数的对比分析。结果本研究中靶区的适形指数及剂量梯度指数R50、全肺的最小剂量及V10、肋骨超过3 cm3体积对应的剂量,两者比较差异均有统计学意义(均P<0.05),其余靶区以及危及器官参数的剂量差异均无统计学意义(均P>0.05),对危及器官和靶区的剂量偏差的纵向比较发现,除了第5例和第9例为患者肺的剂量偏差>5%,第5例患者心脏剂量偏差较大(25%),第9例患者的适形指数偏差>5%外,其余靶区剂量和危及器官剂量都在5%以内。结论本文采用四维剂量重建方法,考虑到了患者治疗期间不同时相下解剖结构变化,并依据不同时相CT在治疗期间的时间权重进行了剂量加权修正,弥补了传统按平均时间剂量权重分配方法的不足,可以更加准确反映患者实际的照射剂量。Objective To introduce a four-dimensional(4D)dose reconstruction method based on real-time tumor motion status during treatment and its application in the dose evaluation of lung cancer patients who have completed stereotactic body radiation therapy(SBRT).Methods A surface-guided radiation therapy(SGRT)system was used to obtain the tumor motion state during the treatment,and the weight of treatment time on different 4D-CT phases during the treatment was calculated with Python software,the weighted dosage under each phase of 4D-CT was recalculated in the treatment planning system(TPS)based on the treatment time weight,each weighted dose was mapped onto average intensity projection CT(AIP-CT)using deformable registration to reconstruct the actually delivered 4D dose.Ten non-small cell lung cancer(NSCLC)patients undergoing SBRT admitted to Zhejiang Provincial People's Hospital from January 2022 to January 2023 were sequentially selected for dose reconstruction and the 4D dosimetric parameters were compared with the traditional three-dimensional(3D)dosimetric evaluation.Results There were statistically significant differences in the conformity index(CI),R50,Lung-DMean,V10,and Ribs'D3(all P<0.05).No significant differences were found for the other parameters(P>0.05).Dose deviation at organs at risk(OAR)and target volume were compared and it was found that the mean deviations of all dosimetric parameters were within 5%.However,for the individualized comparison,it was found that the dose deviation in the lungs of two patients was greater than 5%,the deviation of the heart dose of one patient was relatively large(25%),and the deviation of the CI of another patient was greater than 5%.The remaining target volume dose and OAR dose deviation were all within 5%.Conclusion This article employs a 4D dose reconstruction method,taking into consideration anatomical changes in different phases during the patient's radiation treatment.It performs dose-weighted corrections based on the time-weighting of CT scans at different phases

关 键 词：肿瘤运动 立体定向放疗 光学体表追踪放疗 四维剂量学 非小细胞肺癌 平均密度投影 

分 类 号：R734.2[医药卫生—肿瘤]