摘要
目的 通过比较食管癌容积旋转调强放疗（VMAT）与固定剂量率旋转调强放疗（IMAT）计划,分析VMAT与IMAT在剂量学方面的特点.方法 对入组的22例食管癌患者使用核通Oncentra 4.1计划系统设计IMAT和VMAT两种治疗计划,处方剂量为2 Gy/次,30次.要求≥95％计划靶体积（PTV）达处方剂量,超过110％处方剂量PTV（V11o）＜10％,脊髓最大剂量≤45 Gy,双肺受量V20≤28％,V30≤18％.通过剂量体积直方图统计PTV和正常组织的剂量体积参数,以及机器跳数（MU）、治疗时间和伽马（γ）通过率.SPSS19.0软件对2组数据进行配对t检验分析.结果 显示IMAT组PTV的适形指数（t=3.35,P=0.003）、2％体积所受的剂量（t=-2.27,P=0.034）、肺V30（t=-2.46,P=0.023）均优于VMAT组.VMAT组脊髓V40（t =2.37,P=0.027）、肺V5（t =2.43,P=0.024）要优于IMAT组.PTV、CTV、肿瘤体积（GTV）以及心脏、脊髓、肺V20及平均受量、y通过率差异无统计学意义.结论 IMAT在治疗时间和组织高剂量受照区域要低于VMAT,在MU和组织低剂量受照区域要高于VMAT,两种治疗方式均可满足临床需求,可根据患者实际情况进行选择治疗.
Objective Comparing the dosimetric characteristics of volumetric modulated arc therapy （VMAT） and constant dose rate intensity modulated arc therapy （IMAT） in esophagus cancer to evaluate the per- formance of the two different arc therapy delivery techniques. Methods 22 cases of esophageal cancer patients were selected for the planning comparison study. All plans were done for IMAT and VMAT treatment plans on Oncentra 4.1 treatment planning system, prescription dose of 2 Gy in total 30 fractions. Planning objectives for PTV were at least 95% reached the prescription dose and V110 no more than 10%. The maximum dose of spinalcord below 45 Gy and double lung dose V20 ≤ 28% , V30 ≤ 18% were constrained. Plans were evaluated based onthe ability to meet the dose volume histogram. The dose homogeneity index （HI） , radiation conformity index （CI）, radiation delivery time, monitor units and γ pass rate were also compared. SPSS 19.0 software paired ttest analysis was carried out on the two sets of data. Results The results showed that the IMAT plans in terms of the PTV＇s CI （t =3.35 ,P =0.003）, D2 （t = -2.27,P =0.034） lung＇s V30 （t = -2.46,P =0. 023） were better than that of VMAT group. But the VMAT plans spinal＇s V40 （t = 2.37, P = 0. 027）, lung＇s V5 （t = 2.43, P = 0.024） were superior to that of IMAT plans. There were no significant differences between IMAT and VMAT plans in the average dose of PTV, CTV, GTV, heart, spinal cord, double lung and the γ pass rate. Conclusion IMAT presents a slight improvement in the OAR sparing in high dose with shorter treatment time when compared to VMAT. While in terms of delivered MU and tissue of low dose irradiated area is higher than that of in VMAT. These two treatment methods all can meet the clinical demand, which should be selected according to the actual situation of the patient.
出处
《国际肿瘤学杂志》
CAS
2014年第10期785-788,共4页
Journal of International Oncology
基金
河北省卫生厅医学科学研究重点课题计划（20130253）
关键词
食管肿瘤
放射疗法
放射治疗剂量
Esophageal neoplasms
Radiotherapy
Radiotherapy dosage
