摘要
目的:探讨螺旋断层放射治疗(Helical Tomotherapy, HT)技术和容积旋转调强放射治疗(VMAT)技术在晚期鼻咽癌放疗中的剂量学特点。方法:使用TomoHD～(TM)计划系统对随机选取的10例已行VMAT的晚期鼻咽癌患者制定HT计划。在满足相同处方剂量要求的情况下,评价和比较两种治疗计划中计划靶区(PGTvnx、PGTVnd、PTV1和PTV2)的最小剂量、最大剂量(D_(max))、中位剂量、适形指数、均匀度指数、V_(107)(%)和危及器官受量(脊髓、脑干、晶体、视神经、视交叉、垂体D_(max),颞叶D_(max)和V_(60),腮腺V_(30),颞颌关节V_(50)),并比较两种治疗计划的正常组织B-P受量和总机器跳数。结果:对两种计划的靶区、危及器官以及正常组织剂量学指标采用配对样本t检验。(1)对于靶区剂量学指标,HT计划与VAMT计划相比,靶区PGTVnd的D_(max)和中位剂量略有下降(t=-4.734、-3.341;P=0.001、0.009);HT计划的适形指数好于VMAT计划(t=-0.403, P=0.026);靶区PGTVnd的其它剂量学参数无统计学差异。靶区PGTVnx、PTV1和PTV2的所有剂量学参数均无统计学差异。(2)对于危及器官剂量学指标,HT计划与VMAT计划相比,脑干D_(max)有所降低,有统计学意义(t=-2.309, P=0.046);对侧视神经的D_(max)有所升高,有统计学意义(t=0.050, P=0.002);两侧颞叶的D_(max)有所降低,有统计学意义(t=-4.929、-3.480;P=0.001、0.007);两侧腮腺的V_(30)有所降低,有统计学意义(t=-5.971、-5.603;P=0.000、0.000)。其它危及器官受量,两组计划比较均无统计学意义。(3)正常组织B-P受量比较显示,HT计划相比于VMAT计划,V_5、V_(10)、V_(15)、V_(20)、V_(25)略有增高,有统计学意义(t=9.141、8.409、7.100、5.883、3.560;P=0.000、0.000、0.000、0.000、0.049)。其它剂量学指标无统计学意义。(4)HT计划和VMAT计划单次计划中各射野机器跳数累加之和分别为6 345±210、821±38,有统计学意义(t=-20.234, P=0.000);治疗传输时间分别为(9.1±0.4)、(6
Objective To compare the dosimetric characteristics of helical tomotherapy(HT)and volumetric modulated arc therapy(VMAT)for late-stage nasopharyngeal carcinoma.Methods TomoHDTM planning system was used to design HT plans for 10 randomly selected patients who had been treated with VMAT for late-stage nasopharyngeal carcinoma.Under the condition of meeting the same prescription dose requirements,the dosimetric indexes of planning target areas(PGTvnx,PGTVnd,PTV1 and PTV2)and organs-at-risk(OAR)of the two plans were evaluated and compared.The dosimetric indexes of planning target areas included minimum dose,maximum dose(Dmax),median dose,conformity index and homogeneity index,and V107(%);and the dosimetric indexes of OAR included the Dmax of spinal cord,brain stem,lens,optic nerve,optic chiasma and pituitary,the Dmax andV60 of temporal lobe,the V30 of parotid gland,and the V50 of temporomandibular joint.The dose of normal tissues B-P and total monitor units were also compared between HT plans and VMAT plans.Results Paired sample t test was conducted on the dosimetric indexes of target areas,OAR and normal tissues.No statistical differences were found in the dosimetric parameters of PGTVnd between the two plans,except the Dmax and median dose of PGTVnd which were slightly decreased in HT plans(t=-4.734,-3.341;P=0.001,0.009)and conformity index which was better in HT plan(t=-0.403,P=0.026).All dosimetric parameters of PGTVnx,PTV1 and PTV2 didn't show any statistical differences.The comparison of OAR dose between VMAT plans and HT plans showed that there were statistical differences in some dosimetric indexes,including the Dmax of brain stem which was decreased in HT plan(t=-2.309,P=0.046),the Dmax of contralateral optic nerve which was increased in HT plan(t=0.050,P=0.002),the Dmax on both sides of the temporal lobe which was decreased in HT plan(t=-4.929,-3.480;P=0.001,0.007),the V30 on both sides of the parotid glands which was decreased in HT plan(t=-5.971,-5.603;P=0.000,0.000).As for the other dosimetric indexes of
作者
程婷婷
张彦秋
张子健
黄昕琼
金泽夫
刘归
胡永梅
李钐
申良方
CHENG Tingting;ZHANG Yanqiu;ZHANG Zijian;HUANG Xinqiong;JIN Zefu;LIU Gui;HU Yongmei;LI Shan;SHEN Liangfang(Department of Radiation Oncology,Xiangya Hospital,Central South University,Changsha 410008,China;Department of Radiotherapy,First Hospital of Qinhuangdao,Qinhuangdao 066000,China)
出处
《中国医学物理学杂志》
CSCD
2018年第9期1005-1011,共7页
Chinese Journal of Medical Physics
基金
湖南省卫生计生委科研计划课题(B2017100)
关键词
鼻咽癌
螺旋断层调强放疗
容积旋转调强
剂量学
nasopharyngeal carcinoma
helical tomotherapy
volumetric modulated arc therapy
dosimetry
