局部晚期宫颈癌调强放疗及骨髓限量照射计划设计的剂量学研究  

Intensity Modulated Radiation Therapy and Bone Marrow-sparing Techniques for Locally Advanced Cervical Cancer:A Dosimetric Study

作　　者：顾科[1] 胡群超[1] 翟小明[2] 王建平[2] 张军宁[2] 

机构地区：[1]江苏省苏州市立医院东区放疗科,南京医科大学附属苏州医院放疗科,苏州215001 [2]苏州大学附属第一医院放疗科,苏州215006

出　　处：《华中科技大学学报（医学版）》2016年第4期432-436,453,共6页Acta Medicinae Universitatis Scientiae et Technologiae Huazhong

基　　金：江苏省重点研发计划-社会发展项目(No.BE2015645);江苏省卫生厅科研资助项目(No.Z201413)

摘　　要：目的通过比较局部晚期宫颈癌(LACC)盆腔不同调强放疗(IMRT)计划方式的靶区和危及器官(OAR)剂量分布及实施照射时间(MU值),对LACC的最佳IMRT计划方式进行探讨。此外,通过对盆骨骨髓进行限量与不限量IMRT计划的对比研究,比较两者的骨髓及其他OAR剂量分布的优劣。方法给予10例LACC患者在放疗前进行CT模拟定位并勾画靶区及OAR。宫颈原发肿瘤为大体靶区(GTV),与子宫及宫旁组织、部分阴道、髂总及髂内外、闭孔、骶前淋巴引流区构成临床靶区(CTV)。CTV均匀外放10mm形成计划靶区(PTV)。脊髓、小肠、结肠、直肠、肛管、膀胱、股骨头以及盆骨骨髓等为需要进行限量的OAR。给予6MV X线照射PTV 45Gy/25次。同一患者IMRT设计3种不同的计划,分别为5野调强(IMRT_(5f))、7野调强(IMRT_(7f))和9野调强(IMRT_(9f))。应用剂量体积直方(DVH)图,对3种IMRT计划的优缺点进行分析、比较。通过设计对盆骨骨髓进行限量或不限量的IMRT计划,明确IMRT在降低骨髓受照射量中的价值。结果 3种IMRT计划GTV及PTV的剂量最大值(Dmax)、最小值(Dmin)以及靶区均匀指数(HI)无明显差异。IMRT_(7f)与IMRT_(9f)的膀胱、小肠和直肠的V40明显低于IMRT_(5f),IMRT_(7f)与IMRT_(9f)之间差异无统计学意义。IMRT_(7f)与IMRT_(9f)的适形指数(CI)相比较无明显差别,均明显优于IMRT_(5f)。IMRT_(7f)的MU值显著小于IMRT_(9f),IMRT_(7f)为最佳治疗计划方式。将在此计划基础上对盆骨骨髓进行限量的IMRT计划(BMS-IMRT)与IMRT_(7f)进行比较。两者在GTV及PTV的Dmax、Dmin、靶区HI以及对膀胱、小肠、直肠受照射量的影响无明显差异。BMS-IMRT的CI显著优于IMRT_(7f)。BMS-IMRT明显减少骨髓的V40、V30、V20及V10,分别比IMRT_(7f)减少了16%、10%、16%和16%。结论 LACC的盆腔IMRT计划方式中,IMRT_(7f)方式具有最佳的靶区剂量分布及对OAR的保护,所需照射时间适中,值得推荐应用。对盆骨骨髓进�Objective To examine the dose distribution of target volumes and organs at risk（OAR）and the treatment time in different plans of intensity modulated radiation therapy（IMRT）for locally advanced cervical cancer（LACC）and to assess the dose distribution of bone marrow and OAR in bone marrow-sparing IMRT（BMS-IMRT）.Methods Ten LACC patients underwent CT scanning before radiotherapy,and target volumes and OARs were contoured.The clinical target volume（CTV）included gross tumor volume（GTV）,the uterus,parametrial tissue,part of the vagina,iliac,internal and external iliac,obturator and presacral lymph node regions.The planning target volume（PTV）was comprised of CTV plus a 10 mm margin.OARs included the spinal cord,small intestine,colon,rectum,anus,bladder and femoral head and pelvic bone marrow.PTV was given 45 Gy in 25 fractionations.Three different IMRT treatment schemes（IMRT5f,MRT_（7f） and IMRT9f）were designed for each case and assessed based on dose-volume histogram（DVH）analysis to identify the most suitable plan.Based on the optimal IMRT plan,BMS-IMRT was designed and the value was assessed in reducing the bone marrow exposure.Results There were no significant differences in homogeneity index（HI）,Dmax and Dmin of PTV and GTV among the three IMRT schemes.V40 of IMRT7f and IMRT9f was significantly lower than that of IMRT5f in the bladder,small intestine and rectum.No significant difference was found in V40 between IMRT7f and IMRT9f.The conformation index（CI）in IMRT7f and IMRT9f was superior to that in IMRT5f.Monitor unit（MU）was lower in IMRT7f than in IMRT9f plan.IMRT7f was found to be the optimal IMRT scheme,based on which the BMS-IMRT was designed.Comparison of IMRT7f and BMS-IMRT showed that there were no significant differences in HI,Dmax and Dmin of PTV and GTV and dose distribution of the bladder,small intestine,and rectum.CI was better in BMS-IMRT than in IMRT7f.BMS-IMRT significantly decreased V40,V30,V20 and V10of irradiated bone marrow by16%,10%,16% and 16% a

关 键 词：局部晚期宫颈癌 调强放疗 骨髓 剂量分布 

分 类 号：R737.33[医药卫生—肿瘤]