宫颈癌放疗患者体重指数变化对摆位误差的影响

　　[摘要] 目的 探討体重指数变化对宫颈癌患者放疗摆位误差的影响，利用体重指数变化评估热塑体膜的松紧度，判断是否需重新制作体膜。 方法 收集2014年1月～2015年6月接受外照射放疗、使用体膜体位固定技术的宫颈癌患者60例，监测患者在第1、6、11、16、21、25次放疗时的体重，计算体重指数。在相应的体重指数放疗时应用EPID影像和计划系统所重建的DRR影像比较，得出相应的摆位误差，分析两者的相关性。 结果 患者的体重随着放疗进程的深入，体重逐渐减轻，以最初2周最为明显，之后趋势渐缓至趋于稳定。患者体重指数的变化和放疗的摆位误差呈正相关，变化越大则摆位误差就越大。结果显示：不同体重指数变化组间的左右方向、上下方向、前后方向摆位误差存在统计学差异，两两比较显示体重指数变化>10%组的患者在左右方向、上下方向、前后方向平均摆位误差大于5%～10%组患者，5%～10%组患者在左右方向、上下方向、前后方向平均摆位误差大于<5%组患者。结论 宫颈癌放疗患者的体重指数变化和放疗的摆位误差呈正相关，在临床实践中可利用患者的体重指数变化评估是否需要重新制作热塑体膜。
　　[关键词] 宫颈癌；调强放疗；体重指数变化；摆位误差
　　[中图分类号] R737.33 [文献标识码] A [文章编号] 1673-9701（2018）08-0028-04
　　Effect of body mass index changes on setup error in the patients with cervical cancer after radiotherapy
　　FANG Linming YAN Guiming ZHANG Feiyan CHEN Guofu
　　Room of Radiological Physics， Zhejiang Cancer Hospital， Zhejiang Key Laboratory of Radiological Oncology， Hangzhou 310022， China
　　[Abstract] Objective To investigate the effect of changes of body mass index on the setup error in cervical cancer radiotherapy， and to use the changes of body mass index to evaluate the tightness of the thermoplastic film， so as to determine whether to re-make the body film. Methods Patients who underwent external beam radiotherapy from January 2014 to June 2015 were selected. 60 cases of cervical cancer patients were given body membrane position fixation technique， and patients" body weight in the 1st， 6th， 11st， 16th， 21st， 25th radiotherapy was monitored. The body mass index was calculated. During radiotherapy of the corresponding body mass index， EPID images and reconstructed DRR images by planning system were compared， and the corresponding setup error was obtained. The correlation between the two was analyzed. Results With the process of radiotherapy， the body weight of patients was gradually reduced， which was most significant in the first two weeks， and was gradually stabilized afterwards. The changes of patients" body mass index was positively correlated with the setup error of radiotherapy， and the greater the changes， the greater the setup error. The results showed that there were statistically significant differences in the setup error of different body mass index in the left and right directions， up and down directions and forward and backward directions between the two groups. Pairwise comparisons showed that for the patients with >10% changes of body mass index， the average setup error was more than the patients in the 5%-10% group in the left and right directions， up and down directions and forward and backward directions. The average setup error in the 5%-10% group was more than <5% group in the left and right directions， up and down directions and forward and backward directions. Conclusion The changes of body mass index in patients with cervical cancer undergoing radiotherapy are positively correlated with the setup error of the radiotherapy. In clinical practice， changes in the patient"s body mass index can be used to evaluate whether a thermoplastic film needs to be re-made.

相关热词搜索：放疗 宫颈癌 误差 体重 患者