| 直肠癌术后固定剂量率容积调强放射治疗的初步研究 |
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| 引用本文： | 陈祥,周剑良,王彬冰,李浦,单国平.直肠癌术后固定剂量率容积调强放射治疗的初步研究[J].实用肿瘤学杂志,2018,32(4):327-332. |
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| 作者姓名： | 陈祥 周剑良 王彬冰 李浦 单国平 |
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| 作者单位： | 1.南华大学核科学技术学院(衡阳 421001);2.浙江省肿瘤医院放射物理室;浙江省肿瘤放射治疗重点实验室 |
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| 基金项目： | 基于大数据和人工智能的远程放疗服务模式研究(编号:2017YFC0113201) |
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| 摘 要： | 目的 初步探讨固定剂量率容积调强在直肠癌术后盆腔放射治疗中的可行性。方法 选取10例直肠癌放疗患者,利用RayStation计划系统为每例患者制定可变剂量率容积调强(VDR-VMAT)、固定剂量率容积调强(CDR-VMAT)和5野静态调强(5F-sIMRT)计划。运用剂量体积直方图评估三种计划的靶区、危及器官和正常组织剂量学参数,评估机器总跳数(MU)和计划执行时间。结果 靶区剂量方面,三种计划的靶区D2%、Dmean、D98%、HI和CI在总体上均有差异(P＜0.001)。CDR-VMAT与VDR-VMAT相比较,D2%、Dmean、D98%、HI、CI差异均无统计学意义;CDR-VMAT与5F-sIMRT相比较,D2%减小1.55 Gy(P=0.005)、Dmean减小0.99 Gy(P=0.005)、D98%增大0.60 Gy(P=0.03)、HI值减小(P=0.008)、CI值增大(P=0.008)。危及器官方面,三种计划的膀胱Dmean、V45、V40,小肠Dmean、Dmax、V45,左右股骨头Dmean在总体上均有差异(P＜0.05);小肠V40、V35,左右股骨头V45、V40在总体上均无差异(P＞0.05)。CDR-VMAT与VDR-VMAT相比较,膀胱、小肠、左右股骨头的各剂量学参数差异无统计学意义;CDR-VMAT与5F-sIMRT相比较,膀胱Dmean减小3.05 Gy(P=0.005)、V40减小0.88%(P=0.042),小肠Dmean减小1.75 Gy(P=0.002)、Dmax减小1.70 Gy(P＜0.001),左、右股骨头Dmean减小(P=0.008,0.042)。正常组织低剂量受照体积方面,三种计划的正常组织受照低剂量体积除V10(P=0.497)之外,V5、V15、V20、V25和V30在总体上均有差异(P＜0.001)。CDR-VMAT与VDR-VMAT相比,V5、V10、V15、V20、V25和V30差异无统计学意义;与5F-sIMRT相比,CDR-VMAT的V5减小1.18%(P=0.005)、V15减小0.61%(P=0.022)、V30减小0.80%(P=0.022),V10、V20和V25差异无统计学意义。CDR-VMAT计划的MU为(668.51±45.92),比VDR-VMAT(574.13±50.20)增加16.44%,比5F-sIMRT(537.19±37.34)增加24.45%;CDR-VMAT计划执行时间(3.34±0.22)min是VDR-VMAT(1.76±0.04)min的近两倍,比5F-sIMRT(4~6)min稍短。结论 CDR-VMAT可形成与VDR-VMAT一样高质量的计划,较5F-sIMRT有更优的靶区覆盖率、危及器官保护和正常组织低剂量受照体积。但CDR-VMAT计划的MU比VDR-VMAT和5F-sIMRT增多;执行时间比VDR-VMAT长,比5F-sIMRT稍短。CDR-VMAT初始成本较低,有望为不具备可变剂量率的直线加速器提供额外的旋转放疗的选择。
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| 关 键 词： | 直肠癌 容积调强 静态调强 可变剂量率 固定剂量率 |
| 收稿时间： | 2018-04-01 |
Preliminary study on fixed dose rate volumetric modulated intensity radiotherapy in postoperative patients with rectal cancer |
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| CHEN Xiang,ZHOU Jianliang,WANG Binbing,LI Pu,SHAN Guoping.Preliminary study on fixed dose rate volumetric modulated intensity radiotherapy in postoperative patients with rectal cancer[J].Journal of Practical Oncology,2018,32(4):327-332. |
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| Authors: | CHEN Xiang ZHOU Jianliang WANG Binbing LI Pu SHAN Guoping |
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| Affiliation: | 1.Department of Nuclear Science and Technolory,University of South China,Hengyang 421001,China;2.Department of Radiotherapy Physics/Key Laboratory of Tumor Radiation Therapy,Zhejiang Cancer Hospital |
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| Abstract: | Objective The objective of this study was to investigate the feasibility of fixed dose rate volumetric modulation in pelvic radiotherapy after rectal cancer surgery. Methods Ten patients with rectal cancer radiotherapy were enrolled in this study.The RayStation planning system was used to establish a variable dose rate volumetric modulation(VDR-VMAT),a fixed dose rate volume modulation(CDR-VMAT),and a 5-field static intensity modulated radiation therapy(5F-sIMRT)plans for each patient.Dose volume histograms were used to evaluate the dosimetric parameters of the three planned target area,endangered organs and normal tissue,and to assess the total machine hop count(MU)and planned execution time. Results In terms of target area dose,CDR-VMAT compared to VDR-VMAT,D2%,Dmean,D98%,HI and CI were similar;CDR-VMAT compared to 5F-sIMRT D2%,Dmean,D98%,HI and CI all had statistically significant differences(P＜0.05).In the aspect of OARs,CDR-VMAT compared with VDR-VMAT,all parameters of bladder,small intestine,left and right femoral head were similar;CDR-VMAT compared with 5F-sIMRT,Dmean,V40 of the bladder,Dmean,Dmax of the small intestine,Dmean of the left and right femoral head all had statistically significant differences(P＜0.05).For the normal tissue,CDR-VMAT compared with VDR-VMAT,V5,V10,V15,V20,V25 and V30,were similar;CDR-VMAT compared with 5F-sIMRT,V5,V15 and V30 all had statistically significant differences(P＜0.05).The MU of the CDR-VMAT plan was 16.44% higher than that of VDR-VMAT and 24.45% higher than that of 5F-sIMRT.The execution time of the CDR-VMAT plan was nearly double than that of VDR-VMAT but shorter than that of 5F-sIMRT. Conclusion CDR-VMAT can form a high quality plan as VDR-VMAT with better target coverage,endangering organ protection and low dose exposure volume of normal tissue than 5F-sIMRT.However,the CDR-VMAT plan has more MU than VDR-VMAT and 5F-sIMRT.The execution time of CDR-VMAT is longer than VDR-VMAT and slightly shorter than 5F-sIMRT.The lower initial cost of the CDR-VMAT is expected to provide additional options for rotating radiotherapy for linear accelerators that do not have variable dose rate. |
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| Keywords: | Rectal cancer Volumetric modulated arc therapy Step and shot intensity modulated Variable dose rate Constant dose rate |
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