适形指数在宫颈癌放疗评价中的应用  

Application of conformity index in the evaluation of radiotherapy for cervical carcinoma

作　　者：杨玉刚[1] 齐洪志[1] 许林[1] 郝洁[1] 尚革[1] 张瑞丽[2] YANG Yugang;QI Hongzhi;XU Lin;HAO Jie;SHANG Ge;ZHANG Ruili(Cancer Center,the First Affiliated Hospital of Xinjiang Medical University,Urumqi 830054,China;Postdoctoral Workstation,Changji Branch Hospital of the First Affiliated Hospital of Xinjiang Medical University,Changji 831100,China)

机构地区：[1]新疆医科大学第一附属医院肿瘤中心,新疆乌鲁木齐830054 [2]新疆医科大学第一附属医院昌吉分院博士后工作站,新疆昌吉831100

出　　处：《中国医学物理学杂志》2019年第3期265-270,共6页Chinese Journal of Medical Physics

基　　金：昌吉回族自治州科技计划项目(2018S05)

摘　　要：目的:通过评价宫颈癌放疗计划中靶区的适形度指数,来评价放疗计划的优异性。方法:选择10例宫颈癌患者,每周治疗前做1次CT扫描,扫描的图像在TPS上和首次做放疗计划定位的图像进行融合。然后,在融合图像上勾画靶区、危及器官,将首次放疗计划移植到扫描图像上并对靶区及危及器官进行评价。结果:分别对每位患者开始治疗后CT图像上7野、5野调强,4野适形放疗计划评估与首次治疗计划评估相比较。靶区适形度指数呈正向高度相关(P<0.05),均匀性指数呈弱相关。膀胱、直肠的V_(50)、V_(40)的变化与靶区体积变化呈正相关且变化比较大,而股骨头相对变化较小。小肠最高剂量虽有差异,但不在同一点因而不能准确评价。结论:通过对比发现膀胱、直肠体积变化较大的情况下,适形指数没有差异。因此适形指数可以作为宫颈癌整个放疗疗程评估的标准。Objective To evaluate the radiotherapy plan for cervical cancer with the use of conformity index (CI) of target areas. Methods A total of 10 patients with cervical cancer in the First Affiliated Hospital of Xinjiang Medical University were enrolled in this study. All patients were scanned by CT once a week before treatment. With the use of treatment planning system, the scanned images were fused with the image of the first radiotherapy plan. On the fused image, the target areas and organs-at-risk were segmented. Finally, the first radiotherapy plan was transplanted to the scanned image for further evaluating the dosimetric parameters of target areas and organs-at-risk. Results For each patient, several treatment plans, namely 7- and 5-field intensitymodulated radiotherapy and 4-field conformal radiotherapy plans, were designed in the whole course of radiotherapy for cervical cancer and then compared with the first plan. A strong positive correlation was found between the CI of target areas in treatment plans and the CI of the first plan (P<0.05), and a week correlation was found in homogeneity index. The changes in the V50 and V40 of the bladder and rectum were positively correlated with the target volume, with great changes, but the changes of the femoral head were relatively small. The maximum doses of the small intestine were different. However, because of the peristalsis of small intestine, the maximum dose points of the small intestine were different in all those plans, which resulted in an inaccurate evaluation. Conclusion There was no statistical difference in CI when the volume of bladder and rectum changed greatly. Therefore, CI can be used as a standard for evaluating the whole course of radiotherapy for cervical cancer.

关 键 词：宫颈癌 适形指数 图像融合 

分 类 号：R812[医药卫生—放射医学] R737.3[医药卫生—临床医学]