快速旋转的环型加速器Halcyon鼻咽癌VMAT计划研究  

Dosimetric Study of VMAT Plan with Fast-Rotating Ring Accelerator Halcyon for Nasopharyngeal Carcinoma

作　　者：李珍[1] 余建荣[1] 陈梦豪 杨鑫[2] LI Zhen;YU Jianrong;CHEN Menghao;YANG Xin(Department of Radiation Oncology,Zhongshan City People’s Hospital,Zhongshan Guangdong 528400,China;Sun Yat-sen University Cancer Center,Guangzhou Guangdong 510060,China)

机构地区：[1]中山市人民医院肿瘤分院放疗科,广东中山528400 [2]中山大学肿瘤防治中心,广东广州510060

出　　处：《中国医疗设备》2023年第12期51-56,共6页China Medical Devices

基　　金：广东省基础与应用基础研究基金企业联合基金(2021A1515220140)。

摘　　要：目的比较快速旋转的环型加速器Halcyon双弧(HL2arc)、三弧(HL3arc)鼻咽癌容积旋转调强放疗(Volumetric Modulated ArcTherapy,VMAT)的计划质量和出束时间,并评估Halcyon与传统C型加速器Trilogy在危及器官(Organs atRisk,OARs)保护上的差异。方法选取46例接受VMAT计划的鼻咽癌患者,使用相同的勾画轮廓和剂量限值分别设计HL2arc、HL3arc Halcyon VMAT和Trilogy双弧VMAT计划(T_VMAT)。比较HL2arc和HL3arc的靶区覆盖、OARs的剂量指标和治疗效率,评估Halcyon计划HL3arc和T_VMAT的脊髓、脑干、口腔、喉、眼球的平均剂量D_(mean)。结果所有研究的VMAT计划都达到了目标覆盖率的要求,原发灶PTV_6996的D_(98%)指标HL3arc(6993.08±54.68)cGy高于HL2arc(6983.95±48.38)cGy,D_(2%)指标HL3arc(7412.07±80.97)cGy低于HL2arc(7432.17±81.31)cGy,HL3arc原发灶靶区的覆盖更优且均匀性增加(HI小于HL2arc)。甲状腺、喉、左侧腮腺的平均剂量HL3arc低于HL2arc,左侧腮腺的V_(30)HL3arc降低了1.17%(P<0.05)。相较于Trilogy,脊髓、脑干、甲状腺、口腔和喉的平均剂量HL3arc计划分别降低了856.64、258.27、167.76、169.20、184.83cGy(P<0.05)。HL3arc与HL2arc的机器跳数无统计学差异,出束时间分别为(100.7±4.7)s和(82.6±12.0)s。结论Halcyon鼻咽癌VMAT计划HL3arc的剂量学获益优于HL2arc,与C型Trilogy相比,HL3arc的OARs平均剂量更低。Objective To compare the plan quality and delivery time between the two-arc and triple-arc VMAT plans based on the fastrotating ring accelerator(the Halcyon system)for nasopharyngeal carcinoma,evaluate the advantages of Halcyon in organs at risk(OARs)sparing compared with C-arm accelerator Trilogy.Methods A total of 46 patients with nasopharyngeal carcinoma who received VMAT plan were selected,three sets of radiation therapy plans were generated,under the same policy of contouring and dose constraints:Halcyon VMAT plan with two arcs(HL2arc);and with three arcs(HL3arc);Trilogy VMAT plan(T_VMAT).Target coverage,dose metrics for OARs and therapeutic efficiency were compared between HL2arc and HL3arc respectively.The D_(mean) for spinal cord,brainstem,oral cavity,larynx,and eyeball for Halcyon HL3arc and T_VMAT were evaluated.Results All studied VMAT plans fulfilled the target coverage objectives.The D_(98%) to PTV_6996 of HL3arc(6993.08±54.68)cGy was higher than HL2arc(6983.95±48.38)cGy,D_(2%) of HL3arc(7412.07±80.97)cGy was lower than HL2arc(7432.17±81.31)cGy,resulting in a better coverage and an increased target dose homogeneity for HL3arc(HI less than HL2arc).The HL3arc plan showed the lower Dmean in the thyroid,larynx,L-parotid than those in HL2arc.The volume dose V_(30) of L-parotid in HL3arc plan was reduced by 1.17%(P<0.05).While the mean dose HL3arc plan was reduced by 856.64,258.27,167.76,169.20,and 184.83 cGy in the spinal cord,brainstem,thyroid,oral cavity,and larynx(P<0.05).The monitor unit was no statistical difference,while the beam-on time was(82.6±12)s for HL2arc and(100.7±4.7)s for HL3arc respectively.Conclusion The dosimetric benefits of Halcyon nasopharyngeal carcinoma VMAT plan HL3arc are superior to HL2arc.Compared to C-type Trilogy,HL3arc has lower average OARs doses.

关 键 词：鼻咽癌 环形加速器 Halcyon 旋转容积调强 

分 类 号：R144[医药卫生—公共卫生与预防医学] R730