D2SRS两种照射技术与CyberKnife在脑转移瘤立体定向放疗中的剂量学研究  

Dosimetric comparison of two kinds of radiation techniques of D2SRS and CyberKnife in stereotactic radiotherapy for brain metastases

作　　者：葛瑞刚 解传滨 戴相昆 李纪伟 陈高翔 徐寿平 曲宝林 GE Ruigang;XIE Chuanbin;DAI Xiangkun;LI Jiwei;CHEN Gaoxiang;XU Shouping;QU Baolin(Department of Radiation Oncology,the First Medical Center of Chinese PLA General Hospital,Beijing 100853,China)

机构地区：[1]中国人民解放军总医院第一医学中心放射治疗科,北京100853

出　　处：《中国医学物理学杂志》2020年第3期265-269,共5页Chinese Journal of Medical Physics

基　　金：国家重点研发计划(2017YFC0112105);解放军总医院临床科研扶持基金(2017FC-WJFWZX-04)。

摘　　要：目的:分析基于常规加速器的微光刀(D2SRS)系统两种照射技术在脑转移瘤放疗中的剂量学特性,并与射波刀(Cyber Knife,CK)进行比较,探讨D2SRS在脑转移瘤立体定向放疗的可行性。方法:选取30例已行CK治疗的脑转移瘤病例,分别设计动态调强(DMLC-IMRT)和动态适形拉弧(DCA)两种D2SRS计划,分析其剂量学特性并与CK计划进行比较。结果:3种计划均能实现处方剂量要求,CK计划具有较好的靶区适形度指数(CI,CI=0.82±0.04),但剂量均匀性指数(HI,HI=0.42±0.11)最差。DMLC-IMRT计划具有与CK计划相当的靶区CI(0.80±0.07,P=0.24),且具有更好的HI(0.28±0.13,P=0.00);DCA计划CI(0.69±0.09)最低,但其HI(0.33±0.11)优于CK计划。靶区外剂量跌落方面CK计划更具优势,但相较于DCA计划无统计学意义(P=0.06);在实施时间上,DMLC-IMRT计划[(16.94±1.50)min]与DCA计划[(12.67±0.52)min]相较于CK计划[(38.76±5.60)min]具有明显优势。结论:3种技术均能实现处方剂量要求且CK计划具有更好的靶区适形度,靶区外剂量跌落方面DCA计划优于DMLC-IMRT计划且接近CK计划水平,但在实施效率上两种D2SRS计划具有明显优势,能够在脑转移瘤放疗中更为高效地实现对肿瘤靶区的均匀照射,具有一定的临床应用价值。Objective To analyze the dosimetric characteristics of two radiation techniques of D2 SRS system on conventional accelerator in the radiotherapy for brain metastases,and to compare the two techniques with CyberKnife(CK)for exploring the feasibility of D2 SRS in the stereotactic radiotherapy for brain metastases.Methods Thirty patients with brain metastases who were treated with CK were enrolled in the study,and two different D2 SRS plans,namely DMLC-IMRT plan and DCA plan,were designed for each patient.The dosimetric characteristics of two D2 SRS plans were analyzed and then compared with those of CK plan.Results All 3 kinds of plans met the prescription dose requirements.Among them,CK plan had the best conformity index(CI=0.82±0.04)and the highest homogeneity index(HI=0.42±0.11);the CI in DMLC-IMRT plan was similar to that in CK plan(0.80±0.07 vs 0.82±0.04,P=0.24),and the HI in DMLC-IMRT plan was lower than that in CK plan(0.28±0.13 vs 0.42±0.11,P=0.00);moreover,DCA plan had the lowest CI(0.69±0.09)and a HI(0.33±0.11)lower than CK plan.CK technique had more advantages in dose gradient outside the target areas,but there was no statistical significance compared with DCA plan(P=0.06).The delivery time of DMLC-IMRT plan and DCA plan was(16.94±1.50)min and(12.67±0.52)min,respectively,obviously shorter than(38.76±5.60)min in CK plan.Conclusion All 3 kinds of techniques meet the prescription dose requirements.CK plan has better performances in CI,while DCA plan is superior to DMLC-IMRT and close to CK plan in terms of dose gradient outside target area.Because of the significant advantages in delivery efficiency,two D2 SRS plans can achieve an uniform irradiation in the radiotherapy for brain metastases more efficiently,having certain clinical application value.

关 键 词：脑转移瘤 立体定向放疗 微光刀 射波刀 剂量学 

分 类 号：R318[医药卫生—生物医学工程] R739.41[医药卫生—基础医学]