基于CTVision研究宫颈癌调强放疗中摆位误差对剂量分布的影响  

Study of the Influence of Set-up Errors on Dose Distribution of Intensity-modulated Radiation Therapy for Cervical Cancer Based on CTVision

作　　者：甘晓根[1] 徐子海[1] 廖福锡[1] 

机构地区：[1]中国人民解放军第三零三医院放疗中心,广西南宁530021

出　　处：《中国医疗设备》2013年第9期112-114,共3页China Medical Devices

基　　金：广西科学研究与技术开发计划课题(2011D39)

摘　　要：目的通过测量宫颈癌调强放疗中的摆位误差,分析摆位误差对肿瘤计划靶体积(PTV)及危及器官受照剂量分布的影响。方法 20例宫颈癌患者调强放疗过程中每周1次行CTVision图像引导扫描,其实时扫描图像与计划CT图像融合配准获得X、Y、Z方向上的摆位误差,将上述误差引入治疗计划系统重新计算得到PTV及危及器官的剂量分布参数并与原计划行配对t检验。结果X、Y、Z方向上的摆位误差分别为2.14、5.52、2.47 mm;再计划的PTV 95%体积剂量(D_(95))和最小剂量(Dmin)明显小于原计划(P<0.05);再计划膀胱和直肠接受45 Gy剂量体积(V_(45))明显大于原计划(P<0.05)。结论摆位误差导致PTV D_(95)明显不足,危及器官体积剂量均增加,因此宫颈癌放疗过程中摆位误差的在线纠正是必要的。Objective To analyze the influence of set-up errors on dose distribution of tumor planning target volume （PTV） and organs at risk by measuring the set-up errors of intensity-modulated radiation therapy for cervical cancer. Methods CTVision image guided scanning of 20 patients with cervical cancer was conducted once a week with a total of 5 times during IMRT. The set-up errors on X axis, Y axis and Z axis were obtained through the registration of real-time scanning images and planning CT images of CTVision image guided scanning. The dose distribution parameters of PTV and organs at risk were obtained based on the calculation of set-up errors data with treatment planning system. Then comparing these parameters with those of original plan by paired t-test. Results The average values of set-up errors on X axis, Y axis and Z axis were 2.14, 5.52, 2.47 mm, respectively. The PTV 95% volume dose （D95） and PTV minimal dose of the replanning were lower than those of the original plan （P 〈0.05）. The 45Gy dose volume （V45） received by bladder and rectum of the replanning were higher than those of the original plan（P 〈0.05）. Conclusion The obviously insufficient dose of PTV D95 and increased dose of V45 of the bladder and rectum were caused by setup errors, which indicated that the online adjustment of the setup errors is necessary during the intensity-modulated radiation therapy for cervical cancer.

关 键 词：CTVision图像引导放疗系统 宫颈癌 调强放疗 摆位误差 计划靶体积 临床靶体积 

分 类 号：R815[医药卫生—放射医学] R737.33[医药卫生—临床医学]