基于IGRT技术的宫颈癌调强治疗摆位误差重复性研究

Investigation of the frequency of setup correction for cervical cancer during image-guided radiotherapy in intensity- modulated radiotherapy

目的:利用IGRT技术采集的宫颈癌调强放射治疗前三次的摆位误差,研究宫颈癌的摆位重复性。方法:入组17例进行调强放射治疗的宫颈癌患者。治疗的前三次进行锥形束CT扫描,配准获得患者的摆位误差。分析摆位误差的变化和对三天之内的数据进行两两配对t检验,以获得宫颈癌摆位的重复性规律。结果:数值绝对值矫正后,平移的误差中沿着患者头脚方向的误差大于另外两个方向的误差。任意两组的对比均无统计学意义。结论:宫颈癌摆位中应特别注意沿身体头脚方向的平移误差。治疗中的摆位重复性无规律。再次摆位并没有减少摆位差。应进行多次的CBCT扫描及体位矫正。

Objective： To investigate the frequency of setup correction for cervical cancer during image-guided radiotherapy （ IG-RT） in intensity-modulated radiotherapy （ IMRT） .Methods： 17 patients with cervical cancer were treated by IMRT and IGRT.Cone-beam CT （ CBCT） were acquired at the first, second and third fraction.CBCT and planning CT were registered and got the setup errors.The errors were done the statistic analysis using paired t-test.Results：Using absolute value of setup errors, The aver-age value of y-axis shift （ superior-inferior direction） was obviously larger than other axes.There are no significant in statistics for any two groups of setup error.Conclusion：We must pay attention to the shift of y-axis for cervical cancer during image-guided ra-diotherapy.The setup error was at random each fraction.So we must scan more times using CBCT and correct setup errors to get accu-rate treatment.