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    基于RTOG 0813/0915剂量学指标比较不同技术对非小细胞肺癌立体定向放疗计划的影响

    Effects of different techniques in stereotactic radiotherapy for non-small cell lung cancer based on RTOG 0813/0915 dosimetry index

    • 摘要: 目的 系统评价适形治疗(CRT)、动态适形弧治疗(DCAT)、调强放疗(IMRT)和容积旋转调强治疗(VMAT)等不同非小细胞肺癌体部立体定向放疗(NSCLC-SBRT)技术在美国放射治疗肿瘤协作组(RTOG) 0813/0915剂量学指标和其他全肺受量指标以及治疗效率等方面的差异,选择合适的NSCLC-SBRT技术。方法 回顾分析2019年4月—2021年3月接受SBRT的17例非小细胞肺癌患者的临床资料,分别设计7野CRT、7野IMRT、双弧DCAT和双弧VMAT,比较其靶区RTOG 0813/0915剂量学指标中100%等剂量体积与计划靶体积之比(R100%)、50%等剂量体积与计划靶体积之比(R50%)、距计划靶区 2 cm处的最大剂量(D2cm)和20 Gy剂量照射的体积占肺体积的百分比(V20),以及其他全肺受量指标和治疗效率的差异。结果 4种技术中,在靶区R100%、R50%和D2cm方面,VMAT组最优(P<0.05),IMRT组次之(P<0.05),CRT和DCAT组较差,且2组间差异无统计学意义。VMAT与IMRT组全肺5 Gy剂量照射的体积占肺体积的百分比(V5)、V20及平均剂量(Dmean)均相近(P=0.082,P=0.082,P=0.652),其中VMAT组全肺V20较CRT与DCAT组分别减少13.3%和9.3%(P<0.05)。与IMRT组相比,VMAT组全肺10 Gy剂量照射的体积占肺体积的百分比(V10)、机器跳数(MU)和治疗时间分别减少6.9%、53.1%和18.1%(P<0.05),DCAT组MU和治疗时间分别减少65.4%和36.4%(P<0.05)。与VMAT组相比,DCAT组MU和治疗时间分别减少26.1%和22.3%(P<0.05)。结论 基于医用加速器的NSCLC-SBRT优先推荐VMAT技术,其既能保证RTOG协议的剂量限值要求,又能减少全肺剂量。

       

      Abstract: Objective To systematically evaluate the differences of non-small cell lung cancer-stereotactic body radiation therapy (NSCLC-SBRT) techniques such as conformal radiotherapy (CRT), dynamic conformal arc therapy (DCAT), intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) in The Radiation Therapy Oncology Group (RTOG) 0813/0915 dosimetric index, other whole-lung dose index, and treatment efficacy, and to select appropriate NSCLC-SBRT technology. Methods A total of 17 NSCLC patients who underwent SBRT from April 2019 to March 2021 were enrolled and their clinical data were retrospectively analyzed. The plans included 7-beam CRT, 7-beam IMRT, double arc DCAT and double arc VMAT. They were compared for conformity index (R100%), ratio of 50% isodose volume to the PTV (R50%), maximum dose 2 cm away from PTV in any direction (D2cm), and percent of normal lung receiving 20 Gy (V20) and therapeutic efficacy. Results In terms of target volume R100%, R50% and D2cm in the four plans, the VMAT group was the best (P<0.05), followed by the IMRT group (P<0.05), the CRT and DCAT groups were worse and the difference between the two groups was without statistical difference. The VMAT and IMRT groups had similar percent of normal lung receiving 5 Gy (V5), V20 and mean dose (Dmean) (P=0.082, P=0.082, and P=0.652), where the total lung V20 of the VMAT group was 13.3% and 9.3% lower than that of the CRT and DCAT groups, respectively (P<0.05). Compared with the IMRT group, the total lung percent of normal lung receiving 10 Gy (V10), monitor units (MUs) and treatment time of the VMAT group decreased by 6.9%, 53.1% and 18.1%, respectively (P<0.05), and the V10, MUs and treatment time of the DCAT group decreased by 65.4% and 36.4%, respectively (P<0.05). Compared with the VMAT group, the number of MUs and treatment time in the DCAT group decreased by 26.1% and 22.3%, respectively (P<0.05). Conclusions For NSCLC-SBRT based on medical accelerators, VMAT is preferred, which can not only ensure the dose limit requirements of the RTOG protocol but also reduce the total lung dose.

       

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